Tanto Security has recently disclosed critical vulnerabilities in the open-source service Judge0, which is extensively utilized by various organizations for securely executing sandboxed code. These vulnerabilities, identified as CVE-2024-29021, CVE-2024-28185, and CVE-2024-28189, enable a potential sandbox escape and root access to the host machine, posing a substantial security threat. The service is particularly popular among educational institutions and talent recruitment companies for its ability to safely run arbitrary code. According to the Judge0 website, the platform has 23 clients and over 300 self-hosted instances, along with presumed widespread use in private internal networks.
The discovery and analysis of these vulnerabilities were detailed in a blog post by Tanto Security. The vulnerabilities came to light following a casual conversation about Judge0’s security between a researcher and a friend using the platform. This discussion piqued the researcher’s interest, leading to a deeper investigation into Judge0’s mechanisms and security configurations. It was found that certain oversights in the service’s default setup, such as a generic default password for the Judge0 configuration file, made these vulnerabilities exploitable.
The researcher demonstrated how an attacker could potentially leverage these flaws by submitting multiple entries designed to brute force the default password. This approach could allow attackers to queue up submissions and modify the run arguments of a submission via an SQL query, ultimately enabling a sandbox escape and gaining root access. This kind of vulnerability is particularly dangerous as it allows the execution of arbitrary code with the highest level of privileges on the host machine.
In response to the disclosure, there has been a swift call to action within the cybersecurity community, urging immediate measures to patch the disclosed vulnerabilities and secure all Judge0 instances. Organizations using Judge0 are strongly advised to review and update their configurations, change default passwords, and apply any available security updates to mitigate the risks posed by these vulnerabilities. This event underscores the importance of maintaining rigorous security practices, even in environments that are presumed secure, to protect sensitive data and prevent potential exploitation.
