Tag Archives: Emergent Threat Response

Microsoft SAM File Readability CVE-2021-36934: What You Need to Know

Post Syndicated from Caitlin Condon original https://blog.rapid7.com/2021/07/21/microsoft-sam-file-readability-cve-2021-36934-what-you-need-to-know/

Microsoft SAM File Readability CVE-2021-36934: What You Need to Know

On Monday, July 19, 2021, community security researchers began reporting that the Security Account Manager (SAM) file on Windows 10 and 11 systems was READ-enabled for all local users. The SAM file is used to store sensitive security information, such as hashed user and admin passwords. READ enablement means attackers with a foothold on the system can use this security-related information to escalate privileges or access other data in the target environment.

On Tuesday, July 20, Microsoft issued an out-of-band advisory for this vulnerability, which is now tracked as CVE-2021-36934. As of July 21, 2021, the vulnerability has been confirmed to affect Windows 10 version 1809 and later. A public proof-of-concept is available that allows non-admin users to retrieve all registry hives. Researcher Kevin Beaumont has also released a demo that confirms CVE-2021-36934 can be used to achieve remote code execution as SYSTEM on vulnerable targets (in addition to privilege escalation). The security community has christened this vulnerability “HiveNightmare” and “SeriousSAM.”

CERT/CC published in-depth vulnerability notes on CVE-2021-36934, which we highly recommend reading. Their analysis reveals that starting with Windows 10 build 1809, the BUILTIN\Users group is given RX permissions to files in the %windir%\system32\config directory. If a VSS shadow copy of the system drive is available, a non-privileged user may leverage access to these files to:

  • Extract and leverage account password hashes.
  • Discover the original Windows installation password.
  • Obtain DPAPI computer keys, which can be used to decrypt all computer private keys.
  • Obtain a computer machine account, which can be used in a silver ticket attack.

There is no patch for CVE-2021-36934 as of July 21, 2021. Microsoft has released workarounds for Windows 10 and 11 customers that mitigate the risk of immediate exploitation—we have reproduced these workarounds in the Mitigation Guidance section below. Please note that Windows customers must BOTH restrict access and delete shadow copies to prevent exploitation of CVE-2021-36934. We recommend applying the workarounds on an emergency basis.

Mitigation Guidance

1. Restrict access to the contents of %windir%\system32\config:

  • Open Command Prompt or Windows PowerShell as an administrator.
  • Run this command:
icacls %windir%\system32\config\*.* /inheritance:e

2. Delete Volume Shadow Copy Service (VSS) shadow copies:

  • Delete any System Restore points and Shadow volumes that existed prior to restricting access to %windir%\system32\config.
  • Create a new System Restore point if desired.

Windows 10 and 11 users must apply both workarounds to mitigate the risk of exploitation. Microsoft has noted that deleting shadow copies may impact restore operations, including the ability to restore data with third-party backup applications.

This story is developing quickly. We will update this blog with new information as it becomes available.


SolarWinds Serv-U FTP and Managed File Transfer CVE-2021-35211: What You Need to Know

Post Syndicated from Erick Galinkin original https://blog.rapid7.com/2021/07/12/solarwinds-serv-u-ftp-and-managed-file-transfer-cve-2021-35211-what-you-need-to-know/

SolarWinds Serv-U FTP and Managed File Transfer CVE-2021-35211: What You Need to Know

On July 12, 2021, SolarWinds confirmed an actively exploited zero-day vulnerability, CVE-2021-35211, in the Serv-U FTP and Managed File Transfer component of SolarWinds15.2.3 HF1 (released May 5, 2021) and all prior versions. Successful exploitation of CVE-2021-35211 could enable an attacker to gain remote code execution on a vulnerable target system. The vulnerability only exists when SSH is enabled in the Serv-U environment.

A hotfix for the vulnerability is available, and we recommend all customers of SolarWinds Serv-U FTP and Managed File Transfer install this hotfix immediately (or, at minimum, disable SSH for a temporary mitigation). SolarWinds has emphasized that CVE-2021-35211 only affects Serv-U Managed File Transfer and Serv-U Secure FTP and does not affect any other SolarWinds or N-able (formerly SolarWinds MSP) products. For further details, see SolarWinds’s advisory.


The SolarWinds advisory cites threat intelligence provided by Microsoft. According to Microsoft, a single threat actor unrelated to this year’s earlier SUNBURST intrusions has exploited the vulnerability against a limited, targeted population of SolarWinds customers. The vulnerability exists in all versions of Serv-U 15.2.3 HF1 and earlier. Though Microsoft provided a proof-of-concept exploit to SolarWinds, there are no public proofs-of-concept as of July 12, 2021.

The vulnerability appears to be in the exception handling functionality in a portion of the software related to processing connections on open sockets. Successful exploitation of the vulnerability will cause the Serv-U product to throw an exception, then will overwrite the exception handler with the attacker’s code, causing remote code execution.


Since the vulnerability is in the exception handler, looking for exceptions in the DebugSocketLog.txt file may help identify exploitation attempts. Note, however, that exceptions can be thrown for many reasons and the presence of an exception in the log does not guarantee that there has been an exploitation attempt.

IP addresses used by the threat actor include:

Rapid7 does not use SolarWinds Serv-U FTP products anywhere in our environment and is not affected by CVE-2021-35211.

For further information, see Solarwinds’s FAQ here.

Managed Service Providers Used in Coordinated, Mass Ransomware Attack Impacting Hundreds of Companies

Post Syndicated from boB Rudis original https://blog.rapid7.com/2021/07/13/managed-service-providers-used-in-coordinated-mass-ransomware-attack-impacting-hundreds-of-companies/

Managed Service Providers Used in Coordinated, Mass Ransomware Attack Impacting Hundreds of Companies

Rapid7 is aware of and tracking all information surrounding a coordinated, mass ransomware attack reported to be affecting hundreds of organizations. Huntress Labs is maintaining a public Reddit thread documenting the scope and triage of an event that has, as of the original post date (see updates below), stemmed from 8 managed service providers. Rapid7 does not use Kaseya or a Kaseya MSP and we are not affected by this mass ransomware attack.

Rapid7 is updating this post as more information becomes available. Core information is below the most recent updates.



  • In a video post today, Kaseya has indicated that they are still planning to go ahead with re-enabling an updated VSA SaaS and rollout of the on-prem VSA server update. Some runbook instructions have changed, so any organization planning on going live today should review those changes to see if they impact your environment.


  • The Dutch Institue for Vulnerability Disclosure (DIVD) published more information on the specific vulnerabilities they shared with Kaseya:
    • CVE-2021-30116 – A credentials leak and business logic flaw, resolution in progress. [CVSS 10]
    • CVE-2021-30117 – An SQL injection vulnerability, resolved in May 8th patch. [CVSS 9.8]
    • CVE-2021-30118 – A Remote Code Execution vulnerability, resolved in April 10th patch. (v9.5.6) [CVSS 9.8]
    • CVE-2021-30119 – A Cross Site Scripting vulnerability, resolution in progress. [CVSS 5.4]
    • CVE-2021-30120 – 2FA bypass, resolution in progress. [CVSS 9.9]
    • CVE-2021-30121 – A Local File Inclusion vulnerability, resolved in May 8th patch. [CVSS 6.5]
    • CVE-2021-30201 – A XML External Entity vulnerability, resolved in May 8th patch. [CVSS 7.5]
  • President Biden urged Vladimir Putin to ‘take action to disrupt’ Russia-based hackers behind ransomware attacks.



  • Kaseya has posted runbooks for on premesis VSAs with steps on how to prepare VSA servers for the forthcoming patch. These details include the installation of FireEye’s agent software along with details on how to isolate the server from production networks, and SaaS customers for how to prepare for the SaaS VSAs coming back online.


  • In a statement posted late Monday night, Kaseya provided an update on their assessment of the impact of the attack: "we are aware of fewer than 60 Kaseya customers, all of whom were using the VSA on-premises product, who were directly compromised by this attack. While many of these customers provide IT services to multiple other companies, we understand the total impact thus far has been to fewer than 1,500 downstream businesses. We have not found evidence that any of our SaaS customers were compromised.
  • The Compromise Detection Tool, which was originally only provided directly to customers, has been made public. The tool searches for indicators of compromise, evidence of data encryption, and the REvil ransom note.
  • Kaseya also stated that — based on advice by outside experts — customers who experienced ransomware and receive communication from the attackers should not click on any links as they may be weaponized.


  • Deputy National Security Advisor for Cyber and Emerging Technology Anne Neuberger issued a statement noting that the President has directed the full resources of the government to investigate this incident and urged anyone who believes their systems have been compromised in the Kaseya ransomware incident to immediately report to the Internet Crime Complaint Center at https://www.IC3.gov.
  • The Associated Press is reporting that REvil has offered a blanket decryption for all victims of the Kaseya attack in exchange for $70 million.
  • Incident responders across multiple firms are indicating the number of victim organizations is in the thousands, spanning over 18 countries.


  • Cado Security published resources which can aid responders as they triage theie exposure to the mass ransomware incident.
  • CISA and the FBI have issued guidance for MSPs and their customers who have been affected by the Kaseya VSA supply-chain ransomware attack.

2021-07-03 Update

  • The Washington Post has a story with information on the ransom demands being made
  • The Dutch Institue for Vulnerability Disclosure (DIVD) posted information into their ongoing investigation and response into the Kaseya incident, which includes details on their efforts to identify and secure internet-facing VSA servers.
  • CISA posted an initial advisory and is taking action to understand and address the recent supply-chain ransomware attack.
  • Bloomberg is reporting that the attack (so far) spans over 1,000 organizations across 11 countries with numerous downstream impacts.

Original/Main Content

Evidence points to a supply chain attack targeting Kaseya VSA patch management and monitoring software. Ransom notes suggest REvil is behind the coordinated attack.

Rapid7 Managed Detection and Response teams suggest that, out of an abundance of caution, organizations that use either an on-premise Kaseya VSA solution or the Kaseya cloud-based VSA solution perform the following steps immediately:

  • Disabling or uninstalling the Kaseya agent
  • If you host the Kaseya management server, shut down this system (Kaseya also strongly suggests this course of action)

Kaysea appears to be providing updates via their public helpdesk page and their status page provides visibility into the status of their hosted infrastructure.

Researcher @BushidoToken has provided a link to a GitHub gist containing the REvil configuration dump, which includes indicators of compromise organizations may be able to use to detect evidence of these actors operating in your infrastructure.

Rapid7 Customers

Managed Detection and Response

Rapid7’s Managed Detection and Response (MDR) team had existing attacker behavior detections that identified Kaseya-related ransomware activity beginning on Friday, July 2, 2021. Following the initial wave of alerts on Friday, July 2, MDR sent an email communication with a Critical Advisory to all MDR customers with guidance on disabling Kaseya and mitigating risk. We have conducted hunts across customer environments and deployed additional detections to accelerate identification of the threat. Affected customers have been notified.


Rapid7 has deployed the following detections in InsightIDR for attacker behavior related to the Kaseya ransomware attack:

  • Attacker Technique – CertUtil With Decode Flag
  • Suspicious Process – Renamed CertUtil
  • Suspicious Process – Certutil Decodes Executable File
  • Attacker Tool – KWorking\agent.exe

CVE-2021-1675 (PrintNightmare) Patch Does Not Remediate Vulnerability

Post Syndicated from Erick Galinkin original https://blog.rapid7.com/2021/06/30/cve-2021-1675-printnightmare-patch-does-not-remediate-vulnerability/

CVE-2021-1675 (PrintNightmare) Patch Does Not Remediate Vulnerability

Vulnerability note: Members of the community including Will Dormann of CERT/CC have noted that the publicly available exploits which purport to exploit CVE-2021-1675 may in fact target a new vulnerability in the same function as CVE-2021-1675. Thus, the advisory update published by Microsoft on June 21 does not address these exploits and defenders should be on the look out for a new patch from Microsoft in the future.

On June 8, 2021, Microsoft released an advisory and patch for CVE-2021-1675 (“PrintNightmare”), a critical vulnerability in the Windows Print Spooler. Although originally classified as a privilege escalation vulnerability, security researchers have demonstrated that the vulnerability allows authenticated users to gain remote code execution with SYSTEM-level privileges. On June 29, 2021, as proof-of-concept exploits for the vulnerability began circulating, security researchers discovered that CVE-2021-1675 is still exploitable on some systems that have been patched. As of this writing, at least 3 different proof-of-concept exploits have been made public.

Rapid7 researchers have confirmed that public exploits work against fully patched Windows Server 2019 installations. The vulnerable service is enabled by default on Windows Server, with the exception of Windows Server Core. Therefore, it is expected that in the vast majority of enterprise environments, all domain controllers, even those that are fully patched, are vulnerable to remote code execution by authenticated attackers.

The vulnerability is in the RpcAddPrinterDriver call of the Windows Print Spooler. A client uses the RPC call to add a driver to the server, storing the desired driver in a local directory or on the server via SMB. The client then allocates a DRIVER_INFO_2 object and initializes a DRIVER_CONTAINER object that contains the allocated DRIVER_INFO_2 object. The DRIVER_CONTAINER object is then used within the call to RpcAddPrinterDriver to load the driver. This driver may contain arbitrary code that will be executed with SYSTEM privileges on the victim server. This command can be executed by any user who can authenticate to the Spooler service.

Mitigation Guidance

Since the patch is currently not effective against the vulnerability, the most effective mitigation strategy is to disable the print spooler service itself. This should be done on all endpoints, servers, and especially domain controllers. Dedicated print servers may still be vulnerable if the spooler is not stopped. Microsoft security guidelines do not recommend disabling the service across all domain controllers, since the active directory has no way to remove old queues that no longer exist unless the spooler service is running on at least one domain controller in each site. However, until this vulnerability is effectively patched, this should have limited impact compared to the risk.

On Windows cmd:

net stop spooler

On PowerShell:

Stop-Service -Name Spooler -Force
Set-Service -Name Spooler -StartupType Disabled

The following PowerShell command can be used to help find exploitation attempts:

Get-WinEvent -LogName 'Microsoft-Windows-PrintService/Admin' | Select-String -InputObject {$_.message} -Pattern 'The print spooler failed to load a plug-in module'

Rapid7 Customers

We strongly recommend that all customers disable the Windows Print Spooler service on an emergency basis to mitigate the immediate risk of exploitation. While InsightVM and Nexpose checks for CVE-2021-1675 were released earlier in June, we are currently investigating the feasibility of additional checks to determine whether the print spooler service has been disabled in customer environments.

We will update this blog as further information comes to light.

ForgeRock Access Manager/OpenAM Pre-Auth Remote Code Execution Vulnerability (CVE-2021-35464): What You Need To Know

Post Syndicated from boB Rudis original https://blog.rapid7.com/2021/06/30/forgerock-openam-pre-auth-remote-code-execution-vulnerability-what-you-need-to-know/

ForgeRock Access Manager/OpenAM Pre-Auth Remote Code Execution Vulnerability (CVE-2021-35464): What You Need To Know

On June 29, 2021, security researcher Michael Stepankin (@artsploit) posted details of CVE-2021-35464, a pre-auth remote code execution (RCE) vulnerability in ForgeRock Access Manager identity and access management software. ForgeRock front-ends web applications and remote access solutions in many enterprises.

ForgeRock has issued Security Advisory #202104 to provide information on this vulnerability and will be updating it if and when patches are available.

The weakness exists due to unsafe object deserialization via the Jato framework, with a disturbingly diminutive proof of concept that requires a single GET/POST request for code execution:

GET /openam/oauth2/..;/ccversion/Version?jato.pageSession=<serialized_object>

ForgeRock versions below 7.0 running on Java 8 are vulnerable and the weakness also exists in unpatched versions of the Open Identify Platform’s fork of OpenAM. ForgeRock/OIP installations running on Java 9 or higher are unaffected.

As of July 29, 2021 there are no patches for existing versions of ForgeRock Access Manager. Organizations must either upgrade to version 7.x or apply one of the following workarounds:

Option 1

Disable the VersionServlet mapping by commenting out the following section in the AM web.xml file (located in the /path/to/tomcat/webapps/openam/WEB-INF directory):


To comment out the above section, apply the following changes to the web.xml file:


Option 2

Block access to the ccversion endpoint using a reverse proxy or other method. On Apache Tomcat, ensure that access rules cannot be bypassed using known path traversal issues: Tomcat path traversal via reverse proxy mapping.

The upgrades remove the vulnerable /ccversion HTTP endpoint along with other HTTP paths that used the vulnerable Jato framework.

As of Tuesday, June 29, 2021, Rapid7 Labs has been able to identify just over 1,000 internet-facing systems that appear to be using ForgeRock’s OpenAM solution.

All organizations running ForgeRock OpenAM 7.0.x or lower (or are using the latest release of the Open Identify Platform’s fork of OpenAM) are urged to prioritize upgrading or applying the mitigations within an accelerated patch window if possible, and at the very least within the 30-day window if you are following the typical 30-60-90 day patch criticality cadence.‌‌ Furthermore, organizations that are monitoring web application logs and OpenAM server logs should look for anomalous GET or POST request volume to HTTP path endpoints that include /ccversion in them.

For individual vulnerability analysis, see AttackerKB.

This blog post will be updated with new information as warranted.

Header image photo by Hannah Gibbs on Unsplash

Mass Exploitation of Exchange Server Zero-Day CVEs: What You Need to Know

Post Syndicated from Caitlin Condon original https://blog.rapid7.com/2021/03/03/mass-exploitation-of-exchange-server-zero-day-cves-what-you-need-to-know/

Mass Exploitation of Exchange Server Zero-Day CVEs: What You Need to Know

On March 2, 2021, the Microsoft Threat Intelligence Center (MSTIC) released details on an active state-sponsored threat campaign exploiting four zero-day vulnerabilities in on-premises instances of Microsoft Exchange Server. MSTIC attributes this campaign to HAFNIUM, a group “assessed to be state-sponsored and operating out of China.”

Rapid7 detection and response teams have also observed increased threat activity against Microsoft Exchange Server since Feb. 27, 2021, and can confirm ongoing mass exploitation of vulnerable Exchange instances. Microsoft Exchange customers should apply the latest updates on an emergency basis and take immediate steps to harden their Exchange instances. We strongly recommend that organizations monitor closely for suspicious activity and indicators of compromise (IOCs) stemming from this campaign. Rapid7 has a comprehensive list of IOCs available here.

The actively exploited zero-day vulnerabilities disclosed in the MSTIC announcement as part of the HAFNIUM-attributed threat campaign are:

  • CVE-2021-26855 is a server-side request forgery (SSRF) vulnerability in Exchange that allows an attacker to send arbitrary HTTP requests and authenticate as the Exchange server.
  • CVE-2021-26857 is an insecure deserialization vulnerability in the Unified Messaging service. Insecure deserialization is where untrusted user-controllable data is deserialized by a program. Exploiting this vulnerability gives an attacker the ability to run code as SYSTEM on the Exchange server. This requires administrator permission or another vulnerability to exploit.
  • CVE-2021-26858 is a post-authentication arbitrary file write vulnerability in Exchange. If an attacker could authenticate with the Exchange server, they could use this vulnerability to write a file to any path on the server. They could authenticate by exploiting the CVE-2021-26855 SSRF vulnerability or by compromising a legitimate admin’s credentials.
  • CVE-2021-27065 is a post-authentication arbitrary file write vulnerability in Exchange. An attacker who can authenticate with the Exchange server can use this vulnerability to write a file to any path on the server. They could authenticate by exploiting the CVE-2021-26855 SSRF vulnerability or by compromising a legitimate admin’s credentials.

Also included in the out-of-band update were three additional remote code execution vulnerabilities in Microsoft Exchange. These additional vulnerabilities are not known to be part of the HAFNIUM-attributed threat campaign but should be remediated with the same urgency nonetheless:

Microsoft has released out-of-band patches for all seven vulnerabilities as of March 2, 2021. Security updates are available for the following specific versions of Exchange:

  • Exchange Server 2010 (for Service Pack 3—this is a Defense in Depth update)
  • Exchange Server 2013 (CU 23)
  • Exchange Server 2016 (CU 19, CU 18)
  • Exchange Server 2019 (CU 8, CU 7)

Exchange Online is not affected.

For Rapid7 customers

InsightVM and Nexpose customers can assess their exposure to these vulnerabilities with authenticated vulnerability checks. Customers will need to perform a console restart after consuming the content update in order to scan for these vulnerabilities.

InsightIDR will generate an alert if suspicious activity is detected in your environment. The Insight Agent must be installed on Exchange Servers to detect the attacker behaviors observed as part of this attack. If you have not already done so, install the Insight Agent on your Exchange Servers.

For individual vulnerability analysis, see AttackerKB.

Indiscriminate Exploitation of Microsoft Exchange Servers (CVE-2021-24085)

Post Syndicated from Andrew Christian original https://blog.rapid7.com/2021/03/02/indiscriminate-exploitation-of-microsoft-exchange-servers-cve-2021-24085/

Indiscriminate Exploitation of Microsoft Exchange Servers (CVE-2021-24085)

The following blog post was co-authored by Andrew Christian and Brendan Watters.

Beginning Feb. 27, 2021, Rapid7’s Managed Detection and Response (MDR) team has observed a notable increase in the automated exploitation of vulnerable Microsoft Exchange servers to upload a webshell granting attackers remote access. The suspected vulnerability being exploited is a cross-site request forgery (CSRF) vulnerability: The likeliest culprit is CVE-2021-24085, an Exchange Server spoofing vulnerability released as part of Microsoft’s February 2021 Patch Tuesday advisory, though other CVEs may also be at play (e.g., CVE-2021-26855, CVE-2021-26865, CVE-2021-26857).

The following China Chopper command was observed multiple times beginning Feb. 27 using the same DigitalOcean source IP (

cmd /c cd /d C:\inetpub\wwwroot\aspnet_client\system_web&net group "Exchange Organization administrators" administrator /del /domain&echo [S]&cd&echo [E]

Exchange or other systems administrators who see this command—or any other China Chopper command in the near future—should look for the following in IIS logs:

  • (the source IP of the requests)
  • /ecp/y.js
  • /ecp/DDI/DDIService.svc/GetList

Indicators of compromise (IOCs) from the attacks we have observed are consistent with IOCs for publicly available exploit code targeting CVE-2021-24085 released by security researcher Steven Seeley last week, shortly before indiscriminate exploitation began. After initial exploitation, attackers drop an ASP eval webshell before (usually) executing procdump against lsass.exe in order to grab all the credentials from the box. It would also be possible to then clean some indicators of compromise from the affected machine[s]. We have included a section on CVE-2021-24085 exploitation at the end of this document.

Exchange servers are frequent, high-value attack targets whose patch rates often lag behind attacker capabilities. Rapid7 Labs has identified nearly 170,000 Exchange servers vulnerable to CVE-2021-24085 on the public internet:

Indiscriminate Exploitation of Microsoft Exchange Servers (CVE-2021-24085)

Rapid7 recommends that Exchange customers apply Microsoft’s February 2021 updates immediately. InsightVM and Nexpose customers can assess their exposure to CVE-2021-24085 and other February Patch Tuesday CVEs with vulnerability checks. InsightIDR provides existing coverage for this vulnerability via our out-of-the-box China Chopper Webshell Executing Commands detection, and will alert you about any suspicious activity. View this detection in the Attacker Tool section of the InsightIDR Detection Library.

CVE-2021-24085 exploit chain

As part of the PoC for CVE-2021-24085, the attacker will search for a specific token using a request to /ecp/DDI/DDIService.svc/GetList. If that request is successful, the PoC moves on to writing the desired token to the server’s filesystem with the request /ecp/DDI/DDIService.svc/SetObject. At that point, the token is available for downloading directly. The PoC uses a download request to /ecp/poc.png (though the name could be anything) and may be recorded in the IIS logs themselves attached to the IP of the initial attack.

Indicators of compromise would include the requests to both /ecp/DDI/DDIService.svc/GetList and /ecp/DDI/DDIService.svc/SetObject, especially if those requests were associated with an odd user agent string like python. Because the PoC utilizes aSetObject to write the token o the server’s filesystem in a world-readable location, it would be beneficial for incident responders to examine any files that were created around the time of the requests, as one of those files could be the access token and should be removed or placed in a secure location. It is also possible that responders could discover the file name in question by checking to see if the original attacker’s IP downloaded any files.


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Multiple Unauthenticated Remote Code Control and Execution Vulnerabilities in Multiple Cisco Products

Post Syndicated from boB Rudis original https://blog.rapid7.com/2021/02/25/multiple-unauthenticated-remote-code-control-and-execution-vulnerabilities-in-multiple-cisco-products/

What’s up?

Multiple Unauthenticated Remote Code Control and Execution Vulnerabilities in Multiple Cisco Products

On Feb. 24, 2021, Cisco released many patches for multiple products, three of which require immediate attention by organizations if they are running affected systems and operating system/software configurations. They are detailed below:

Cisco ACI Multi-Site Orchestrator Application Services Engine Deployment Authentication Bypass Vulnerability (CVSSv3 Base 10; CVE-2021-1388)

Cisco Security Advisory

Cisco Multi-Site Orchestrator (MSO) is the product responsible for provisioning, health monitoring, and managing the full lifecycle of Cisco Application Centric Infrastructure (ACI) networking policies and tenant policies across all Cisco ACI sites organizations have deployed. It essentially has full control over every aspect of networking and network security. Furthermore, Cisco ACI can be integrated with and administratively control VMware vCenter Server, Microsoft System Center VMM [SCVMM], and OpenStack controller virtualization platform managers.

A weakness in an API endpoint of Cisco ACI MSO installed on the Application Services Engine could allow an unauthenticated, remote attacker to bypass authentication on an affected device. One or more API endpoints improperly validated API tokens and a successful exploit gives an unauthenticated, remote attacker full control over this powerful endpoint.

This vulnerability affects Cisco ACI Multi-Site Orchestrator (MSO) running a 3.0 release of software only when deployed on a Cisco Application Services Engine. Only version 3.0 (3m) is vulnerable.

Thankfully, this vulnerability was discovered internally, reducing the immediate likelihood of proof-of-concept exploits being available.

Organizations are encouraged to restrict API access to trusted, segmented networks and ensure this patch is applied within critical patch change windows.

Cisco Application Services Engine Unauthorized Access Vulnerabilities (CVSSv3 Base 9.8; CVE-2021-1393, CVE-2021-1396)

Cisco Security Advisory

CVE-2021-1393 allows unauthenticated, remote attackers access to a privileged service on affected devices. One service running on the ASE Data Network has insufficient access controls which can be exploited by attackers via specially crafted TCP requests. Successful exploits result in privileged device access enabling the running of containers and execution of any host-level commands.

CVE-2021-1396 allows unauthenticated, remote attackers access to a privileged service on affected devices. This, too, affects a service API with lax access controls on the Data Network. Successful exploitation results in significant information disclosure, creation of support-level artifacts on an isolated volume, and the ability to manipulate an undocumented subset of configuration settings.

The ASE Data Network provides the following services:

  • Cisco Application Services Engine Clustering
  • App to app communication
  • Access to the management network of the Cisco ACI fabric
  • All app-to-ACI fabric communications

The Data Network is not the same as the Management Network, thus segmentation is not an option for temporary mitigation.

These vulnerabilities affect Cisco ASE software released 1.1 (3d) and earlier.

Again, thankfully, this vulnerability was discovered internally, reducing the immediate likelihood of proof-of-concept exploits being available.

Organizations are encouraged to ensure this patch is applied within critical patch change windows.

Cisco NX-OS Software Unauthenticated Arbitrary File Actions Vulnerability (CVSSv3 Base 9.8; CVE-2021-1361)

Cisco Security Advisory

CVE-2021-1361 enables remote, unauthenticated attackers to create, modify, or delete arbitrary files with the privileges of the root user on Cisco Nexus 3000 and 9000 series switches in standalone NX-OS mode.

Cisco has provided more technical information on this critical vulnerability than they have for the previous two, disclosing that a service running on TCP port 9075 improperly listens and responds to external communication requests. Specially crafted TCP requests can result in sufficient permissions to perform a cadre of actions, including creating a local user account without administrators (or log collectors) knowing.

Organizations can use the following command line on standalone NX-OS Nexus 3000/9000’s to determine if this service is listening externally:

nexus# show sockets connection | include 9075
tcp LISTEN 0 32 * : 9075

Only Nexus 3000/9000 series switches in standalone NX-OS mode are affected.

Organizations are encouraged to restrict Cisco management and control plane access to trusted, segmented networks and use on-device access control lists (ACLs) to block external requests to TCP port 9075. Once mitigations are performed, organizations should ensure this patch is applied within critical patch change windows. However, please note that this vulnerability was discovered by an external, anonymous reporter, which likely means there is at least one individual/group outside of Cisco that knows how to exploit this weakness. Such information may affect patch prioritization decisions in some organizations.

Rapid7 will update this post as more information is provided or proof-of-concept exploits are discovered.


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VMware vCenter Server CVE-2021-21972 Remote Code Execution Vulnerability: What You Need to Know

Post Syndicated from boB Rudis original https://blog.rapid7.com/2021/02/24/vmware-vcenter-server-cve-2021-21972-remote-code-execution-vulnerability-what-you-need-to-know/

VMware vCenter Server CVE-2021-21972 Remote Code Execution Vulnerability: What You Need to Know

This blog post was co-authored by Bob Rudis and Caitlin Condon.

What’s up?

On Feb. 23, 2021, VMware published an advisory (VMSA-2021-0002) describing three weaknesses affecting VMware ESXi, VMware vCenter Server, and VMware Cloud Foundation.

Before digging into the individual vulnerabilities, it is vital that all organizations that use the HTML5 VMware vSphere Client, i.e., VMware vCenter Server (7.x before 7.0 U1c, 6.7 before 6.7 U3l and 6.5 before 6.5 U3n) and VMware Cloud Foundation (4.x before 4.2 and 3.x before immediately restrict network access to those clients—especially if they are not segmented off on a management network—implement the mitigation noted below, and consider performing accelerated/immediate patching on those systems.

Vulnerability details and recommendations

CVE-2021-21972 is a critical (CVSSv3 base 9.8) unauthenticated remote code execution vulnerability in the HTML5 vSphere client. Any malicious actor with access to port 443 can exploit this weakness and execute commands with unrestricted privileges.

PT Swarm has provided a detailed walkthrough of this weakness and how to exploit it.

Rapid7 researchers have independently analyzed, tested, and confirmed the exploitability of this weakness and have provided a full technical analysis.

Proof-of-concept working exploits are beginning to appear on public code-sharing sites.

Organizations should restrict access to this plugin and patch affected systems immediately (i.e., not wait for standard patch change windows).

VMware has provided steps for a temporary mitigation, which involves disabling the plugin.

CVE-2021-21973 is an important (CVSSv3 base 8.8) heap-overflow-based remote code execution vulnerability in VMware ESXi OpenSLP. Attackers with same-segment network access to port 427 on affected systems may be able to use the heap-overflow weakness to perform remote code execution.

VMware has provided steps for a temporary mitigation, which involves disabling the SLP service on affected systems.

Rapid7 recommends applying the vendor-provided patches as soon as possible after performing the vendor-recommended mitigation.

CVE-2021-21974 is a moderate (CVSSv3 base 5.3) server-side request forgery vulnerability affecting the HTML5 vSphere Client. Attackers with access to port 443 of affected systems can use this weakness to gain access to underlying system information.

VMware has provided steps for a temporary mitigation, which involves disabling the plugin.

Since attackers will already be focusing on VMware systems due to the other high-severity weaknesses, Rapid7 recommends applying the vendor-provided patches as soon as possible after performing the vendor-recommended mitigation.

Attacker activity

Rapid7 Labs has not detected broad scanning for internet-facing VMware vCenter servers, but Bad Packets has reported that they’ve detected opportunistic scanning. We will continue to monitor Project Heisenberg for attacker activity and update this blog post as we have more information.


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SonicWall SNWLID-2021-0001 Zero-Day and SolarWinds’ 2021 CVE Trifecta: What You Need to Know

Post Syndicated from boB Rudis original https://blog.rapid7.com/2021/02/03/sonicwall-snwlid-2021-0001-zero-day-and-solarwinds-2021-cve-trifecta-what-you-need-to-know/

SonicWall SNWLID-2021-0001 Zero-Day and SolarWinds’ 2021 CVE Trifecta: What You Need to Know

Not content with the beating it laid down in January, 2021 continues to deliver with an unpatched zero-day exposure in some SonicWall appliances and three moderate-to-critical CVEs in SolarWinds software. We dig into the details below.

Urgent mitigations required for SonicWall SMA 100 Series appliances

On Jan. 22, 2021, SonicWall published an advisory and in-product notification that they had identified a coordinated attack on their internal systems by highly sophisticated threat actors exploiting probable zero-day vulnerabilities on certain SonicWall secure remote access products.

Specifically, they identified Secure Mobile Access (SMA) version 10.x running on the following physical SMA 100 appliances running firmware version 10x, as well as the SMA 500v virtual appliance:

  • SMA 200
  • SMA 210
  • SMA 400
  • SMA 410

On Jan. 31, 2021, NCC Group Research & Technology confirmed and demonstrated exploitability of a possible candidate for the vulnerability and detected indicators that attackers were exploiting this weakness.

On Feb. 3, 2021, SonicWall released a patch to firmware version SMA, which all impacted organizations should apply immediately.

SonicWall has recommended removing all SMA 100 Series appliances for SMA 500v virtual appliances from the internet until a patch is available. If this is not possible, organizations are strongly encouraged to perform the following steps:

  • Enable multi-factor authentication. SonicWall has indicated this is a “critical” step until the patch is available.
  • Reset user password for all SMA 100 appliances.
  • Configure the web application firewall on the SMA 100 series, which has been updated with rules to detect exploitation attempts (SonicWall indicates that this is normally a subscription-based software, but they have automatically provided 60-day complementary licenses to organizations affected by this vulnerability).

If it’s not possible to perform these steps, SonicWall recommends that organizations downgrade their SMA 100 Series appliances to firmware version 9.x. They do note that this will remove all settings and that the devices will need to be reconfigured from scratch.

Urgent patching required for SolarWinds Orion and Serv-U FTP products

On Feb. 3, 2021, Trustwave published a blog post providing details on two vulnerabilities in the SolarWinds Orion platform and a single vulnerability in the SolarWinds Serv-U FTP server for Windows.

The identified Orion platform weaknesses include:

  • CVE-2021-25274: Trustwave discovered that improper/malicious use of Microsoft Message Queue (MSMQ) could allow any remote, unprivileged attacker to execute arbitrary code in the highest privilege.
  • CVE-2021-25275: Trustwave discovered that credentials are stored insecurely, allowing any local user to take complete control over the SOLARWINDS_ORION database. This could lead to further information theft, and also enables attackers to add new admin-level users to all SolarWinds Orion platform products.

The identified SolarWinds Serv-U FTP server for Windows weakness enables any local user to create a file that can define a new Serv-U FTP admin account with full access to the C:\ drive, which will then give them access or replace any directory or file on the server.

Trustwave indicated they have private, proof-of-concept code that will be published on Feb. 9, 2021.

SolarWinds Orion Platform users can upgrade to version 2020.2.4. SolarWinds ServU-FTP users can upgrade to version 15.2.2 Hotfix 1.

Rapid7 vulnerability researchers have identified that after the Orion Platform patch is applied, there is a digital signature validation step performed on arrived messages so that messages having no signature or not signed with a per-installation certificate are not further processed. On the other hand, the MSMQ is still unauthenticated and allows anyone to send messages to it.

Rapid7 response

Rapid7 Labs is keeping a watchful eye on Project Heisenberg for indications of widespread inventory scans (attackers looking for potentially vulnerable systems) and will provide updates, as warranted, on any new developments.

Our InsightVM coverage team is currently evaluating options for detecting the presence of these vulnerabilities.


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