Gogs OpenSSH Vulnerability: the popular open-source self-hosted Git service, faced a critical security challenge in early 2024. Four vulnerabilities were discovered that could have allowed attackers to steal, modify, or even delete sensitive source code hosted on vulnerable Gogs servers. This blog post delves into these vulnerabilities, their potential impact, and the crucial steps you can take to mitigate the risks.
Understanding the Gogs OpenSSH Vulnerabilities (CVE-2024-39930 to CVE-2024-39933)
The vulnerabilities discovered by SonarSource researchers targeted Gogs versions up to 0.13.0. Here’s a breakdown of each vulnerability:
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CVE-2024-39930 (Critical): Argument Injection in Built-in SSH Server – This vulnerability resided in the built-in SSH server of Gogs. An attacker with a valid SSH private key could exploit a flaw in how Gogs processed certain SSH requests, potentially allowing them to inject and execute malicious code on the server. This could grant them complete control over the system.
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CVE-2024-39931 (Critical): Deletion of Internal Files – This vulnerability allowed an authenticated attacker to delete critical internal files on the Gogs server. This could have crippled the functionality of the service or even exposed sensitive data.
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CVE- 2024-39932 (Critical): Argument Injection During Changes Preview – This vulnerability existed in the way Gogs processed code changes before they were committed. A malicious user could inject code that would be executed when previewing changes, potentially allowing them to steal information or gain unauthorized access.
- CVE-2024-39933 (Medium): Argument Injection When Tagging New Releases – This vulnerability, while less severe than the others, still posed a risk. It allowed an attacker to inject malicious code when tagging new releases in a Gogs repository.
Gogs OpenSSH Vulnerability:Important points to note:
- All these vulnerabilities required the attacker to be authenticated, meaning they needed a valid user account on the Gogs server.
- Exploiting CVE-2024-39930 depended on the built-in SSH server being enabled, the specific version of the
envbinary used, and a valid SSH key. - Gogs instances running on Windows and Docker images were not exploitable due to differences in how they handled the
envcommand.
Potential Impact of These Vulnerabilities
The potential impact of these vulnerabilities could have been devastating for organizations relying on Gogs to host their source code. Here’s what a successful attack could have entailed:
- Source Code Theft: Attackers could have stolen sensitive code, intellectual property, or confidential information from repositories.
- Source Code Manipulation: Malicious code could have been injected into repositories, potentially leading to software vulnerabilities or backdoors in downstream applications.
- Denial of Service (DoS): By deleting internal files, attackers could have rendered the Gogs server inoperable, disrupting development workflows.
- Escalation of Privileges: Exploiting CVE-2024-39930 could have allowed attackers to gain complete control over the server, potentially compromising other systems on the network.
How to Mitigate the Risks
Thankfully, these vulnerabilities have been addressed. Here’s how to ensure your Gogs instance is secure:
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Upgrade Immediately: The most critical step is to upgrade your Gogs server to the latest version (currently beyond 0.13.0). Up-to-date versions will have the necessary patches to address these vulnerabilities.
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Disable Built-in SSH Server (if not needed): If you’re not using the built-in SSH server functionality, it’s advisable to disable it to eliminate the attack surface associated with CVE-2024-39930.
- Examine User Access Controls: Make sure you’ve implemented robust user access controls. Restrict administrative rights and refrain from giving needless access to private files.
- Turn on Two-Factor Authentication (2FA): By requiring a second authentication factor in addition to a login and password, 2FA offers an extra degree of protection. Even in the event that an attacker manages to gain legitimate credentials, this greatly lowers the likelihood of illegal access.
- Keep Up to Date: Frequently check for Gogs-related security updates and advisories. In order to be updated about any upcoming vulnerabilities, think about subscribing to Gogs security notifications.In summary
The Gogs vulnerabilities of 2024 are a clear reminder of how crucial it is to maintain constant security awareness. You may greatly lower the risk of attacks by maintaining the most recent version of your software, putting strong access controls in place, and keeping up with new threats.
