Post Syndicated from Caitlin Condon original https://blog.rapid7.com/2024/01/23/etr-cve-2024-0204-critical-authentication-bypass-in-fortra-goanywhere-mft/

On January 22, 2024, Fortra published a security advisory on CVE-2024-0204, a critical authentication bypass affecting its GoAnywhere MFT secure managed file transfer product prior to version 7.4.1. The vulnerability is remotely exploitable and allows an unauthorized user to create an admin user via the administration portal. Fortra lists the root cause of CVE-2024-0204 as CWE-425: Forced Browsing , which is a weakness that occurs when a web application does not adequately enforce authorization on restricted URLs, scripts, or files.

Fortra evidently addressed this vulnerability in a December 7, 2023 release of GoAnywhere MFT, but it would appear they did not issue an advisory until now.

In February 2023, a zero-day vulnerability (CVE-2023-0669) in GoAnywhere MFT was exploited in a large-scale extortion campaign conducted by the Cl0p ransomware group. It’s unclear from Fortra’s initial advisory whether CVE-2024-0204 has been exploited in the wild, but we would expect the vulnerability to be targeted quickly if it has not come under attack already, particularly since the fix has been available to reverse engineer for more than a month. Rapid7 strongly advises GoAnywhere MFT customers to take emergency action.

Mitigation guidance

CVE-2024-0204 affects the following versions of GoAnywhere MFT:

• Fortra GoAnywhere MFT 6.x from 6.0.1
• Fortra GoAnywhere MFT 7.x before 7.4.1

GoAnywhere MFT customers who have not already updated to a fixed version (7.4.1 or higher) should do so on an emergency basis, without waiting for a regular patch cycle to occur.

Per the vendor advisory, “the vulnerability may also be eliminated in non-container deployments by deleting the InitialAccountSetup.xhtml file in the install directory and restarting the services. For container-deployed instances, replace the file with an empty file and restart. For additional information, see https://my.goanywhere.com/webclient/ViewSecurityAdvisories.xhtml (registration required).”

If you are unable to update to a fixed version, Fortra has offered two manual mitigation pathways:

• Deleting the InitialAccountSetup.xhtml file in the installation directory and restarting the services.
• Replacing the InitialAccountSetup.xhtml file with an empty file and restarting the services.

Rapid7 customers

InsightVM and Nexpose customers will be able to assess their exposure to CVE-2024-0204 with an unauthenticated vulnerability check expected to be available in today’s (January 23) content release.

Post Syndicated from Caitlin Condon original https://blog.rapid7.com/2024/01/11/etr-zero-day-exploitation-of-ivanti-connect-secure-and-policy-secure-gateways/

On Wednesday, January 10, 2024, Ivanti disclosed two zero-day vulnerabilities affecting their Ivanti Connect Secure and Ivanti Policy Secure gateways. Security firm Volexity, who discovered the vulnerabilities, also published a blog with information on indicators of compromise and attacker behavior observed in the wild. In an attack Volexity investigated in December 2023, the two vulnerabilities were chained to gain initial access, deploy webshells, backdoor legitimate files, capture credentials and configuration data, and pivot further into the victim environment.

The two vulnerabilities in the advisory are:

• CVE-2023-46805, an authentication bypass vulnerability in the web component of Ivanti Connect Secure (9.x, 22.x) and Ivanti Policy Secure that allows a remote attacker to access restricted resources by bypassing control checks.
• CVE-2024-21887, a critical command injection vulnerability in web components of Ivanti Connect Secure (9.x, 22.x) and Ivanti Policy Secure that allows an authenticated administrator to send specially crafted requests and execute arbitrary commands on the appliance. This vulnerability can be exploited over the internet

Rapid7 urges customers who use Ivanti Connect Secure or Policy Secure in their environments to take immediate steps to apply the workaround and look for indicators of compromise. Volexity have released an extensive description of the attack and indicators of compromise — we strongly recommend reviewing their blog, which includes the information below:

“Volexity observed the attacker modifying legitimate ICS components and making changes to the system to evade the ICS Integrity Checker Tool. Notably, Volexity observed the attacker backdooring a legitimate CGI file (compcheck.cgi) on the ICS VPN appliance to allow command execution. Further, the attacker also modified a JavaScript file used by the Web SSL VPN component of the device in order to keylog and exfiltrate credentials for users logging into it. The information and credentials collected by the attacker allowed them to pivot to a handful of systems internally, and ultimately gain unfettered access to systems on the network.”

Ivanti Connect Secure, previously known as Pulse Connect Secure, is a security appliance that has been targeted in a range of threat campaigns in recent years. The U.S. Cybersecurity and Infrastructure Security Agency (CISA) also released a bulletin on January 10, 2024 urging Ivanti Connect Secure and Ivanti Policy Secure users to mitigate the two vulnerabilities immediately.

Counts of internet-exposed appliances vary widely depending on the query used. The following Shodan query identifies roughly 7K devices on the public internet, while looking for Ivanti’s welcome page alone more than doubles that number (but reduces accuracy): http.favicon.hash:-1439222863 html:"welcome.cgi?p=logo. Rapid7 Labs has observed scanning activity targeting our honeypots that emulate Ivanti Connect Secure appliances.

Mitigation guidance

All supported versions (9.x and 22.x) of Ivanti Connect Secure and Ivanti Policy Secure are vulnerable to CVE-2023-46805 and CVE-2024-21887.  Ivanti’s advisory notes that a workaround is available for CVE-2023-46805 and CVE-2024-21887. Ivanti Connect Secure and Ivanti Policy Secure customers should apply the vendor-supplied workaround immediately and investigate their environments for signs of compromise. Ivanti advises customers using unsupported versions of the product to upgrade to a supported version before applying the workaround.

Ivanti has indicated that patches will be released in a staggered schedule between January 22 and February 19, 2024 — target patch timelines can be found here.

Per Ivanti’s advisory and KB article, “Ivanti Neurons for ZTA gateways cannot be exploited when in production. If a gateway for this solution is generated and left unconnected to a ZTA controller, then there is a risk of exploitation on the generated gateway. Ivanti Neurons for Secure Access is not vulnerable to these CVEs; however, the gateways being managed are independently vulnerable to these CVEs.”

Note: Volexity indicated that adversaries have been observed wiping logs and/or disabling logging on target devices. Administrators should ensure logging is enabled. Ivanti has a built-in integrity checker tool (ICT) that verifies the image on Ivanti Connect Secure and Ivanti Policy Secure appliances and looks for modified files. Ivanti is advising customers to use the external version of this tool to check the integrity of the ICS/IPS images, since Ivanti has seen adversaries “attempting to manipulate” the internal integrity checker tool.

Rapid7 customers

Our engineering team is investigating options for InsightVM and Nexpose coverage for these vulnerabilities. We will provide an update to this blog no later than 3 PM EST on Thursday, January 11, 2024.

Post Syndicated from Caitlin Condon original https://blog.rapid7.com/2023/11/09/etr-cve-2023-47246-sysaid-zero-day-vulnerability-exploited-by-lace-tempest/

On November 8, 2023, IT service management company SysAid disclosed CVE-2023-47426, a zero-day path traversal vulnerability affecting on-premise SysAid servers. According to Microsoft’s threat intelligence team, who said they discovered the vulnerability, it has been exploited in the wild by DEV-0950 (Lace Tempest) in “limited attacks.” In a social media thread published the evening of November 8, Microsoft emphasized that Lace Tempest distributes the Cl0p ransomware, and that exploitation of CVE-2023-47246 is likely to result in ransomware deployment and/or data exfiltration. Lace Tempest is the same threat actor who perpetrated the MOVEit Transfer and GoAnywhere MFT extortion attacks earlier this year.

SysAid’s advisory on CVE-2023-47246 says the attacker “uploaded a WAR archive containing a WebShell and other payloads into the webroot of the SysAid Tomcat web service.” Post-exploitation behavior included deployment of MeshAgent remote administration tooling and GraceWire malware. There are extensive details about the attack chain in the vendor advisory, along with robust indicators of compromise. An employee of technology company Elastic also reported the evening of November 8 that Elastic had observed exploitation in the wild as far back as October 30.

SysAid’s website claims that the company has upwards of 5,000 customers, including a number of large corporations whose logos adorn SysAid’s customer page. Shodan searches for either a specific CSS file or the favicon both return only 416 instances of SysAid exposed to the public internet. (Note that “exposed” does not necessarily imply that those instances are vulnerable.)

Mitigation guidance

CVE-2023-47246 is fixed in version 23.3.36 of SysAid server. Given the potential for ransomware and extortion attacks, organizations with on-premise SysAid servers should apply the vendor-supplied patches on an emergency basis, invoking incident response procedures if possible, and ensure the server is not exposed to the public internet. We also strongly recommend reviewing the indicators of compromise in SysAid’s advisory and examining environments for suspicious activity, though notably, the advisory says the adversaries may cover their tracks by cleaning up logs and artifacts on disk.

Indicators of compromise

SysAid has an extensive list of IOCs and observed attacker behavior in their advisory. Rather than reproducing that here, we urge organizations to use that vendor advisory as their starting source of truth for threat hunting: https://www.sysaid.com/blog/service-desk/on-premise-software-security-vulnerability-notification

Rapid7 has a Velociraptor artifact available to help organizations identify post-exploitation activity related to this zero-day vulnerability:

• Yara.Process: Targets observed malware and Cobalt Strike via process YARA
• Disk.Ntfs: Targets known disk IOCs via Windows.ntfs.mft
• Forensic.Usn: Targets known disk IOCs via USN journal
• Evtx.Defender: Searches Defender event logs for evidence of associated alerts
• Evtx.NetworkIOC: Targets known strings of network IOCs in firewall, Sysmon and PowerShell logs

Rapid7 customers

InsightVM and Nexpose customers will be able to assess their exposure to CVE-2023-47246 with an authenticated Windows check expected to ship in today’s (November 9) content release.

InsightIDR and Managed Detection and Response customers have existing detection coverage through Rapid7’s expansive library of detection rules. Rapid7 recommends installing the Insight Agent on all applicable hosts to ensure visibility into suspicious processes and proper detection coverage. Below is a non-exhaustive list of detections that are deployed and will alert on post-exploitation behavior related to this zero-day vulnerability:

• Attacker Technique – SpoolSV Spawns CMD or PowerShell
• Attacker Technique – Possible Process Injection
• Attacker Technique – PowerShell Download Cradles
• Attacker Tool – CobaltStrike PowerShell Commands
• Suspicious Network Connection – Destination Address in Cobalt Strike C2 List

Post Syndicated from Caitlin Condon original https://blog.rapid7.com/2023/10/17/etr-cve-2023-20198-active-exploitation-of-cisco-ios-xe-zero-day-vulnerability/

On Monday, October 16, Cisco’s Talos group published a blog on an active threat campaign exploiting CVE-2023-20198, a “previously unknown” zero-day vulnerability in the web UI component of Cisco IOS XE software. IOS XE is an operating system that runs on a wide range of Cisco networking devices, including routers, switches, wireless controllers, access points, and more. Successful exploitation of CVE-2023-20198 allows a remote, unauthenticated attacker to create an account on an affected device and use that account to obtain full administrator privileges, effectively enabling a complete takeover of the system.

There is no patch for CVE-2023-20198 as of October 17, 2023. As Cisco Talos noted in their blog, it is being actively exploited in the wild. There appear to be a significant number of devices running IOS XE on the public internet as of October 17. Estimates of internet-exposed devices running IOS XE vary, but the attack surface area does appear to be relatively large; one estimate puts the exposed device population at 140K+.

In the activity Cisco observed, attackers created (malicious) local user accounts from suspicious IP addresses. Additional activity has included deployment of an implant that allows the attacker to execute arbitrary commands at the system level or IOS level. Cisco has an extensive description of the malicious behavior they’ve observed here.

Affected products

Cisco’s public advisory on CVE-2023-20198 merely says that Cisco IOS XE software is vulnerable if the web UI feature is enabled (the UI is enabled through the ip http server or ip http secure-server commands). Cisco does not offer a list of products that definitively run IOS XE, but their product page for IOS XE lists some, including the Catalyst, ASR, and NCS families.

According to the advisory, customers can determine whether the HTTP Server feature is enabled for a system, by logging into the system and using the show running-config | include ip http server|secure|active command in the CLI to check for the presence of the ip http server command or the ip http secure-server command in the global configuration. The presence of either command or both commands in the system configuration indicates that the web UI feature is enabled (and that the system is therefore vulnerable).

Cisco’s advisory also specifies that if the ip http server command is present and the configuration also contains ip http active-session-modules none, the vulnerability is not exploitable over HTTP. If the ip http secure-server command is present and the configuration also contains ip http secure-active-session-modules none, the vulnerability is not exploitable over HTTPS.

Mitigation guidance

In lieu of a patch, organizations should disable the web UI (HTTP Server) component on internet-facing systems on an emergency basis. To disable the HTTP Server feature, use the no ip http server or no ip http secure-server command in global configuration mode. Per Cisco’s advisory, if both the HTTP server and HTTPS server are in use, both commands are required to disable the HTTP Server feature. Organizations should also avoid exposing the web UI and management services to the internet or to untrusted networks.

Disabling the web UI component of IOS XE systems and limiting internet exposure reduces risk from known attack vectors, but notably does not mitigate risk from implants that may have already been successfully deployed on vulnerable systems. Rapid7 recommends invoking incident response procedures where possible to prioritize hunting for indicators of compromise Cisco has shared, listed below.

Cisco-observed attacker behavior

The Cisco Talos blog on CVE-2023-21098 has a full analysis of the implant they’ve observed being deployed as part of this threat campaign. We strongly recommend reading the analysis in its entirety. The implant is saved under the file path /usr/binos/conf/nginx-conf/cisco_service.conf that contains two variable strings made up of hexadecimal characters. While the implant is not persistent (a device reboot will remove it), the attacker-created local user accounts are.

Cisco observed the threat actor exploiting CVE-2021-1435, which was patched in 2021, to install the implant after gaining access to a device vulnerable to CVE-2023-20198. Talos also notes that they have seen devices fully patched against CVE-2021-1435 getting the implant successfully installed “through an as of yet undetermined mechanism.”

Indicators of compromise

The Cisco Talos blog on CVE-2023-20198 directs organizations to look for unexplained or newly created users on devices running IOS XE. One way of identifying whether the implant observed by Talos is present is to run the following command against the device, where the "DEVICEIP” portion is a placeholder for the IP address of the device to check:

curl -k -X POST "https[:]//DEVICEIP/webui/logoutconfirm.html?logon_hash=1"

The command above will execute a request to the device’s Web UI to see if the implant is present. If the request returns a hexadecimal string, the implant is present (note that the web server must have been restarted by the attacker after the implant was deployed for the implant to have become active). Per Cisco’s blog, the above check should use the HTTP scheme if the device is only configured for an insecure web interface.

Additional Cisco IOCs

• 5.149.249[.]74
• 154.53.56[.]231

Usernames:

• cisco_tac_admin
• cisco_support

Cisco Talos also advises performing the following checks to determine whether a device may have been compromised:

Check the system logs for the presence of any of the following log messages where “user” could be cisco_tac_admin, cisco_support or any configured, local user that is unknown to the network administrator:

• %SYS-5-CONFIG_P: Configured programmatically by process SEP_webui_wsma_http from console as user on line

• %SEC_LOGIN-5-WEBLOGIN_SUCCESS: Login Success [user: user] [Source: source_IP_address] at 03:42:13 UTC Wed Oct 11 2023

Note: The %SYS-5-CONFIG_P message will be present for each instance that a user has accessed the web UI. The indicator to look for is new or unknown usernames present in the message.

Organizations should also check the system logs for the following message where filename is an unknown filename that does not correlate with an expected file installation action:

• %WEBUI-6-INSTALL_OPERATION_INFO: User: username, Install Operation: ADD filename

Rapid7 customers

InsightVM and Nexpose customers can assess their exposure to CVE-2023-20198 with an authenticated vulnerability check that looks for Cisco IOS XE devices with the web UI enabled. The check is available in today’s (October 17) content release.

Rapid7 Managed Detection and Response (MDR) customers have existing detection coverage through Rapid7’s expansive library of detection rules. The following detection rules are deployed and alerting on activity related to this vulnerability via the IP addresses provided by Cisco:

• Network Flow – CURRENT_EVENTS Related IP Observed
• Suspicious Connection – CURRENT_EVENTS Related IP Observed

Post Syndicated from Caitlin Condon original https://blog.rapid7.com/2023/10/04/etr-cve-2023-22515-zero-day-privilege-escalation-in-confluence-server-and-data-center/

On October 4, 2023, Atlassian published a security advisory on CVE-2023-22515, a critical privilege escalation vulnerability affecting on-premises instances of Confluence Server and Confluence Data Center. Atlassian does not specify the root cause of the vulnerability or where exactly the flaw resides in Confluence implementations, though the indicators of compromise include mention of the /setup/* endpoints.

The advisory indicates that “Atlassian has been made aware of an issue reported by a handful of customers where external attackers may have exploited a previously unknown vulnerability in publicly accessible Confluence Data Center and Server instances to create unauthorized Confluence administrator accounts and access Confluence instances.”

It’s unusual, though not unprecedented, for a privilege escalation vulnerability to carry a critical severity rating. Atlassian’s advisory implies that the vulnerability is remotely exploitable, which is typically more consistent with an authentication bypass or remote code execution chain than a privilege escalation issue by itself. It’s possible that the vulnerability could allow a regular user account to elevate to admin — notably, Confluence allows for new user sign-ups with no approval, but this feature is disabled by default.

Since CVE-2023-22515 has been exploited in user environments, Atlassian recommends that on-premises Confluence Server and Data Center customers update to a fixed version immediately, or else implement mitigations. The advisory notes that “Instances on the public internet are particularly at risk, as this vulnerability is exploitable anonymously.” Indicators of compromise are included in the advisory and are reproduced in the Mitigation guidance section below.

Affected Products

The following versions of Confluence Server and Data Center are affected:

• 8.0.0
• 8.0.1
• 8.0.2
• 8.0.3
• 8.0.4
• 8.1.0
• 8.1.1
• 8.1.3
• 8.1.4
• 8.2.0
• 8.2.1
• 8.2.2
• 8.2.3
• 8.3.0
• 8.3.1
• 8.3.2
• 8.4.0
• 8.4.1
• 8.4.2
• 8.5.0
• 8.5.1

Versions prior to 8.0.0 are not affected by this vulnerability. Atlassian Cloud sites are not affected by this vulnerability. Confluence sites accessed via an atlassian.net domain are hosted by Atlassian and are not vulnerable to this issue.

Fixed versions:

• 8.3.3 or later
• 8.4.3 or later
• 8.5.2 (Long Term Support release) or later

For more information, refer to the Atlassian advisory and release notes.

Mitigation guidance

On-prem Confluence Server and Confluence Data Center customers should upgrade to a fixed version immediately, restricting external network access to vulnerable systems until they are able to do so. The Atlassian advisory says that known attack vectors can be mitigated by blocking access to the /setup/* endpoints on Confluence instances. Directions on doing this are in the advisory.

Atlassian recommends checking all affected Confluence instances for the following indicators of compromise:

• Unexpected members of the confluence-administrator group
• Unexpected newly created user accounts
• Requests to /setup/*.action in network access logs
• Presence of /setup/setupadministrator.action in an exception message in atlassian-confluence-security.log in the Confluence home directory

Rapid7 customers

InsightVM and Nexpose customers will be able to assess their exposure to CVE-2023-22515 with a version-based vulnerability check expected to be available in today’s (October 4) content release.

Post Syndicated from Caitlin Condon original https://blog.rapid7.com/2023/09/29/etr-critical-vulnerabilities-in-ws_ftp-server/

On September 27, 2023, Progress Software published a security advisory on multiple vulnerabilities affecting WS_FTP Server, a secure file transfer solution. There are a number of vulnerabilities in the advisory, two of which are critical (CVE-2023-40044 and CVE-2023-42657).

Rapid7 is not aware of any exploitation in the wild as of September 29, 2023. Our research team has identified what appears to be the .NET deserialization vulnerability (CVE-2023-40044) and confirmed that it is exploitable with a single HTTPS POST request and a pre-existing ysoserial.net gadget.

The vulnerabilities in the advisory span a range of affected versions, and several affect only WS_FTP servers that have the Ad Hoc Transfer module enabled. Nevertheless, Progress Software’s advisory urges all customers to update to WS_FTP Server 8.8.2, which is the latest version of the software. Rapid7 echoes this recommendation.The vendor advisory has guidance on upgrading, along with info on disabling or removing the Ad Hoc Transfer module.

The critical vulnerabilities are below — notably, NVD scores CVE-2023-40044 as only being of “high” severity, not critical:

• CVE-2023-40044: In WS_FTP Server versions prior to 8.7.4 and 8.8.2, the Ad Hoc Transfer module is vulnerable to a .NET deserialization vulnerability that allows an unauthenticated attacker to execute remote commands on the underlying WS_FTP Server operating system. The vulnerability affects all versions of the WS_FTP Server Ad Hoc module. Progress Software’s advisory indicates that WS_FTP Server installations without the Ad Hoc Transfer module installed are not vulnerable to CVE-2023-40044.
• CVE-2023-42657: WS_FTP Server versions prior to 8.7.4 and 8.8.2 are vulnerable to a directory traversal vulnerability that allows an attacker to perform file operations (delete, rename, rmdir, mkdir) on files and folders outside of their authorized WS_FTP folder path.  Attackers could also escape the context of the WS_FTP Server file structure and perform the same level of operations (delete, rename, rmdir, mkdir) on file and folder locations on the underlying operating system.

Additional (non-critical) vulnerabilities are listed below. See Progress Software’s advisory for full details:

• CVE-2023-40045: In WS_FTP Server versions prior to 8.7.4 and 8.8.2, the Ad Hoc Transfer module is vulnerable to reflected cross-site scripting (XSS). Delivery of a specialized payload could allow an attacker to execute malicious JavaScript within the context of the victim’s browser.
• CVE-2023-40046: The WS_FTP Server manager interface in versions prior to 8.7.4 and 8.8.2 is vulnerable to  SQL injection, which could allow an attacker to infer information about the structure and contents of the database and execute SQL statements that alter or delete database elements.
• CVE-2023-40047: The WS_FTP Server Management module in versions prior to 8.8.2 is vulnerable to stored cross-site scripting (XSS), which could allow an attacker with administrative privileges to import an SSL certificate with malicious attributes containing cross-site scripting payloads.  Once the cross-site scripting payload is successfully stored, an attacker could leverage this vulnerability to target WS_FTP Server admins with a specialized payload which results in the execution of malicious JavaScript within the context of the victim’s browser.  
• CVE-2023-40048: The Manager interface in WS_FTP Server version prior to 8.8.2 was missing cross-site request forgery (CSRF) protection on a POST transaction corresponding to a WS_FTP Server administrative function.
• CVE-2023-40049: In WS_FTP Server version prior to 8.8.2, an unauthenticated user could enumerate files under the ‘WebServiceHost’ directory listing.  
• CVE-2022-27665: WS_FTP Server 8.6.0 is vulnerable to reflected XSS (via AngularJS sandbox escape expressions), which allows an attacker to execute client-side commands by inputting malicious payloads in the subdirectory search bar or Add folder filename boxes. For example, there is Client-Side Template Injection via subFolderPath to the ThinClient/WtmApiService.asmx/GetFileSubTree URI.

Mitigation guidance

Progress Software security advisories have borne increased scrutiny and garnered broader attention from media, users, and the security community since the Cl0p ransomware group’s May 2023 attack on MOVEit Transfer. Secure file transfer technologies more generally continue to be popular targets for researchers and attackers.

While these vulnerabilities are not known to be exploited by adversaries at this time, we would advise updating to a fixed version as soon as possible, without waiting for a typical patch cycle to occur. As noted in the advisory, “upgrading to a patched release using the full installer is the only way to remediate this issue. There will be an outage to the system while the upgrade is running.”

The optimal course of action is to update to 8.8.2 as the vendor has advised. If you are using the Ad Hoc Transfer module in WS_FTP Server and are not able to update to a fixed version, consider disabling or removing the module.

See Progress Software’s advisory for the latest information.

Rapid7 customers

InsightVM and Nexpose customers running WS_FTP will be able to assess their exposure to all eight of the CVEs in this blog with authenticated vulnerability checks expected to be available in today’s (September 29) content release.

Post Syndicated from Caitlin Condon original https://blog.rapid7.com/2023/09/25/etr-cve-2023-42793-critical-authentication-bypass-in-jetbrains-teamcity-ci-cd-servers/

On September 20, 2023, JetBrains disclosed CVE-2023-42793, a critical authentication bypass vulnerability in on-premises instances of their TeamCity CI/CD server. Successful exploitation of CVE-2023-42793 allows an unauthenticated attacker with HTTP(S) access to a TeamCity server to perform a remote code execution attack and gain administrative control of the server — making the vulnerability a potential supply chain attack vector.

As of September 25, 2023, Rapid7 is not aware of in-the-wild exploitation of CVE-2023-42793, and no public exploit code is available. We still recommend, however, that TeamCity customers upgrade to the fixed version (2023.05.4) immediately, or else apply one of the vulnerability-specific patches outlined in the JetBrains advisory. Customers who are unable to upgrade or apply a targeted fix for CVE-2023-42793 should consider taking the server offline until the vulnerability can be mitigated.

Affected Products

CVE-2023-42793 affects all on-prem versions of JetBrains TeamCity prior to 2023.05.4. TeamCity Cloud is not affected, and according to JetBrains, TeamCity Cloud servers have already been upgraded to the latest version.

Mitigation Guidance

JetBrains notes in their advisory that vulnerability-specific security patch plugins (i.e., hot fixes) are available as a temporary workaround for TeamCity customers who are not able to upgrade to 2023.05.4. The plugins are supported on TeamCity 8.0+ and will mitigate CVE-2023-42793 specifically, but will not address any other security issues or bugs that are included in the full 2023.05.4 upgrade.

Security patch plugins:

• TeamCity 2018.2 to 2023.05.3
• TeamCity 8.0 to 2018.1

For TeamCity 2019.2 and later, the plugin can be enabled without restarting the TeamCity server. For versions older than 2019.2, a server restart is required after the plugin has been installed. TeamCity customers should refer to the JetBrains advisory on CVE-2023-42793 for the latest information.

Rapid7 strongly recommends upgrading to the fixed version of the software (2023.05.4) as soon as possible rather than relying solely on workarounds.

Rapid7 Customers

InsightVM and Nexpose customers will be able to assess their exposure to CVE-2023-42793 with a remote vulnerability check targeted for today’s (September 25) content release.