In the world of agile software development, issue tracking and project management tools play an essential role. JetBrains YouTrack is a popular application designed to streamline processes and effectively manage projects. However, any software's security and stability are only as strong as the underlying codes that hold it together.

In this in-depth analysis, we will discuss the discovery of a critical vulnerability (CVE-2022-24442) in JetBrains YouTrack, which could potentially lead to severe consequences, such as leaking sensitive data or even gaining unauthorized access to a system by exploiting Server-Side Template Injection (SSTI). We will dive into the nature of this exploit, provide coding examples, and refer to the original research material.

Description of the Vulnerability

Affected Versions: JetBrains YouTrack before 2021.4.40426

Vulnerability Type: Server-Side Template Injection (SSTI)

Severity: High

JetBrains YouTrack versions before 2021.4.40426 were found to be vulnerable to SSTI via the FreeMarker template engine. Attackers who could access the YouTrack instance could exploit this vulnerability by injecting malicious code within FreeMarker templates, which are then executed on the server side, leading to unauthorized access.

FreeMarker is an open-source Java-based template engine widely used in web applications and serves many purposes, such as generating HTML pages, emails, and SQL queries. Being an essential part of JetBrains YouTrack, the discovery of an SSTI vulnerability significantly jeopardizes the application's security.

Understanding Server-Side Template Injection (SSTI)

Server-Side Template Injection is a type of application attack in which an attacker can inject malicious content or code into server-side templates. These templates are often used as placeholders or dynamic scripts to generate content or process data. When the influenced templates are rendered on the server, malicious code can be executed, leading to devastating consequences like data leaks or Remote Code Execution (RCE).

Exploit Details

The vulnerability caused by the FreeMarker templates in JetBrains YouTrack could be exploited by injecting unsafe content in a template, which is then executed on the server-side. An example of a malicious payload can be seen in the following code snippet:

<#assign ex=”freemarker.template.utility.Execute”>${ ex(static_cast("ping example.com"))}

In this payload, the assignment directive (<#assign>) creates dangerous objects dynamically via the FreeMarker engine. The freemarker.template.utility.Execute function allows the execution of arbitrary system commands. In the above case, it injects ping, which communicates with example.com. If successful, this malicious injection demonstrates that an attacker can execute arbitrary commands on the server hosting a vulnerable YouTrack application.

Mitigation and Patching

JetBrains has released a patch addressing this critical vulnerability (YouTrack 2021.4.40426). It is highly recommended to update your YouTrack instance to the latest version immediately. For patching instructions, please visit JetBrains YouTrack's documentation on how to update your install:

- Instructions for updating YouTrack Standalone: 8a2ce727ba8859dbf238dbbe26025d9fdeebdfc-babd6c5a2a1124a8b80a803dac081bda.ssl.cf1.rackcdn.com/youtrack/secure/administration/Upgrading+an+Installed+YouTrack+Standalone.html

- Instructions for updating YouTrack InCloud: 8a2ce727ba8859dbf238dbbe26025d9fdeebdfc-babd6c5a2a1124a8b80a803dac081bda.ssl.cf1.rackcdn.com/youtrack/secure/administration/Upgrading+to+a+New+YouTrack+InCloud+Version.html

Conclusion

Investigating and understanding vulnerabilities like CVE-2022-24442 in popular applications like JetBrains YouTrack is crucial in maintaining a secure environment and safeguarding sensitive information. As the software grows and evolves, new exploits might surface, emphasizing the importance of staying informed and taking preventative measures. Always ensure you keep your applications up to date and pay close attention to the latest security bulletins.

Timeline

Published on: 02/25/2022 20:15:00 UTC
Last modified on: 03/04/2022 02:56:00 UTC