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CVE-2023-42793: JetBrains TeamCity Authentication Bypass Vulnerability

CVE-2023-42793 is rated critical with a CVSS v3.1 base score of 9.8 and affects JetBrains TeamCity. Per its scoring, it can be exploited over the network, without authentication, without any user interaction. The scored impact on confidentiality, integrity and availability is the highest available. CISA added it to its Known Exploited Vulnerabilities catalog on 2023-10-04, which means exploitation in the wild has been observed.

Vulnerability description

In JetBrains TeamCity before 2023.05.4 authentication bypass leading to RCE on TeamCity Server was possible

Severity breakdown

CVSS v3.1 9.8: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

• Attack vector: Network. Exploitable remotely over the network, with no need for local or physical access.
• Attack complexity: Low. No special conditions; the attack can be repeated reliably.
• Privileges required: None. No account or prior access is needed.
• User interaction: None. No action from any user is needed.
• Scope: Unchanged. Impact stays within the vulnerable component.
• Confidentiality impact: High. Total loss of confidentiality; sensitive data can be fully disclosed.
• Integrity impact: High. Total loss of integrity; data or system state can be fully modified.
• Availability impact: High. Total loss of availability; the component can be shut down.

Underlying weakness

CWE-288: Authentication Bypass Using an Alternate Path or Channel

The product requires authentication, but the product has an alternate path or channel that does not require authentication.

CWE-306: Missing Authentication for Critical Functionality

The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.

Affected products

• Jetbrains Teamcity: before 2023.05.4

References

• https://blog.jetbrains.com/teamcity/2023/09/cve-2023-42793-vulnerability-post-mortem/
• https://www.jetbrains.com/privacy-security/issues-fixed/
• http://packetstormsecurity.com/files/174860/JetBrains-TeamCity-Unauthenticated-Remote-Code-Execution.html
• https://attackerkb.com/topics/1XEEEkGHzt/cve-2023-42793
• https://www.rapid7.com/blog/post/2023/09/25/etr-cve-2023-42793-critical-authentication-bypass-in-jetbrains-teamcity-ci-cd-servers/
• https://www.sonarsource.com/blog/teamcity-vulnerability/
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-42793
• https://www.securityweek.com/recently-patched-teamcity-vulnerability-exploited-to-hack-servers/