JetBrains TeamCity CI/CD fixes critical vulnerabilites

published: Sept. 25, 2023

Take action: Time for an urgent action. First lock down your TeamCity server from the internet if possible. Then patch. If you can't lock down the server from the internet, patch immediately! Changing all secrets and reviewing code in a hacked server is a nightmare.

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JetBrains TeamCity, a widely used and highly customizable Continuous Integration (CI/CD) server has a critical security vulnerability tracked as CVE-2023-42793 (CVSS score 9.8). This vulnerability is an authentication bypass issue affecting the on-premises version of TeamCity.

Exploiting this flaw allows an attacker to steal source code, stored service secrets, and private keys of the targeted organization. Furthermore, by injecting malicious code, the attacker can compromise the integrity of software releases, causing a ripple effect on downstream users.

TeamCity server version 2023.05.3 and below are susceptible to this authentication bypass, enabling unauthorized attackers to achieve remote code execution (RCE) on the server. The vulnerability grants an attacker the ability to not only steal sensitive assets but also manipulate the software release process, endangering downstream users. Disturbingly, this attack doesn't necessitate any user interaction.

A Shodan scan reveals that more than 3,000 on-premises TeamCity servers are exposed to the internet, heightening the risk associated with this vulnerability. JetBrains responded by addressing the vulnerability in version 2023.05.4, ensuring that the issue no longer affects TeamCity Cloud.

JetBrains strongly advised users to update their servers to the latest version to benefit from a multitude of security updates beyond this particular fix. For users unable to update to version 2023.05.4, a security patch plugin was made available for download and installation, specifically targeting versions 2018.2 to 2023.05.3 and versions 8.0 to 2018.1. 

No details are available about the exploit of the vulnerability due to its ease of exploitation.

JetBrains TeamCity CI/CD fixes critical vulnerabilites