The Jenkins Script Security Plugin is a widely used tool for controlling script executions in Jenkins. It helps to ensure the scripts being executed are safe and secure, but recently, a vulnerability has been identified in Jenkins Script Security Plugin 1189.vb_a_b_7c8fd5fde and earlier versions. This vulnerability, known as CVE-2022-45379, exposes the plugin to collision attacks due to its reliance on the SHA-1 hashing algorithm.

Exploit Details

Jenkins Script Security Plugin stores whole-script approvals as the SHA-1 hash of the script. The SHA-1 hashing algorithm has been proven to be vulnerable to collision attacks in recent years. In simple terms, a collision attack is when two different input strings (in this case, scripts) produce the same hash output. This poses a significant security risk, as threat actors could potentially submit a malicious script that has the same SHA-1 hash as the approved benign script, and the plugin would not be able to identify the difference between the two. Consequently, the malicious script could be executed without any security measures in place, potentially compromising the Jenkins deployment and its underlying infrastructure.

Here's a hypothetical code snippet highlighting the vulnerable implementation of the Script Security Plugin:

public class ScriptSecurityPlugin {
  private Map<String, ScriptApproval> approvals;

  public void approveScript(String script) {
    String sha1Hash = sha1(script);
    ScriptApproval approval = new ScriptApproval(script);
    
    approvals.put(sha1Hash, approval);
  }

  public boolean isScriptApproved(String script) {
    String sha1Hash = sha1(script);
    return approvals.containsKey(sha1Hash);
  }

  public String sha1(String input) {
    // Implementation using SHA-1 hashing algorithm
  }
}

In the code snippet above, the Script Security Plugin is approving and checking script approvals using the SHA-1 hashes of the script. This implementation is what makes the plugin vulnerable to collision attacks.

The issue has been identified and reported by the Jenkins security team in their security advisory for the Script Security Plugin. Detailed information on this vulnerability can be found through the following resources:

1. Jenkins Security Advisory 2022-03-23: https://www.jenkins.io/security/advisory/2022-03-23/
2. Jenkins Script Security Plugin: https://plugins.jenkins.io/script-security/
3. CVE-2022-45379: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-45379

Mitigation

As a temporary solution, Jenkins administrators can assess and monitor the approved scripts stored within their environment to ensure that only approved and verified scripts are being executed.

The Jenkins security team is actively working on addressing the vulnerability and has released an updated version of the Jenkins Script Security Plugin that uses a more secure hashing algorithm, mitigating the risk of collision attacks. Jenkins administrators should update their Script Security Plugin to the latest version as soon as possible.

Conclusion

CVE-2022-45379 is a critical vulnerability affecting Jenkins Script Security Plugin 1189.vb_a_b_7c8fd5fde and earlier versions. Jenkins administrators must take immediate steps to mitigate this security risk by monitoring their approved scripts and updating their Script Security Plugin to the most recent version. By doing so, they can better protect their Jenkins deployment and infrastructure from potential threats and maintain the overall security and integrity of their systems.

Timeline

Published on: 11/15/2022 20:15:00 UTC
Last modified on: 11/18/2022 20:26:00 UTC