A recently discovered vulnerability, tracked as CVE-2024-11696, affects the handling of exceptions in the loadManifestFromFile method during add-on signature verification in Firefox and Thunderbird. The flaw, triggered by an invalid or unsupported extension manifest, could cause runtime errors that disrupted the signature validation process. Consequently, the enforcement of signature validation for unrelated add-ons might have been bypassed.
This post details the vulnerability, its potential impact, and the affected software versions. We also provide code snippets illustrating the problem and links to the original references. Lastly, we outline the necessary steps to mitigate the vulnerability.
Vulnerability Details
The core of the issue lies in the loadManifestFromFile method, responsible for handling the extension manifest during the add-on signature verification process. Applications failed to account for exceptions thrown by this method when parsing an invalid or unsupported manifest file.
try {
loadManifestFromFile(invalidManifestFile);
} catch (error) {
// No proper error handling
}
As a result, runtime errors could occur, disrupting the signature validation process for subsequent add-ons. As a consequence, the enforcement of signature validation for unrelated add-ons might have been compromised.
Although this issue does not directly allow attackers to tamper with user extensions, it could weaken the overall security of the affected software as signature validation is used to ensure that third-party applications on the user's computer have not tampered with the user's extensions.
The vulnerability was reported by researchers in the Mozilla Security Advisory
- Mozilla Foundation Security Advisory 2024-08
- CVE-2024-11696 on the NVD Database
- Bugzilla Report for CVE-2024-11696
Exploiting the Vulnerability
Although exploiting this vulnerability might be challenging, attackers may attempt to use malformed or unsupported extension manifests to trigger the exception during the signature validation process. By doing so, they may bypass the enforcement of signature validation for unrelated add-ons.
Mitigation
To mitigate the vulnerability, users are advised to update their Firefox and Thunderbird installations to the latest versions:
Thunderbird ESR – update to version 128.5 or higher
Updating the software ensures that the unhandled exceptions issue is fixed, which helps maintain the integrity of the add-on signature validation process.
Conclusion
CVE-2024-11696 is a potentially dangerous vulnerability, potentially bypassing the enforcement of signature validation for unrelated add-ons in Firefox and Thunderbird. By updating the affected software to the latest versions, users can mitigate the issue and maintain the overall security of their systems.
Timeline
Published on: 11/26/2024 14:15:19 UTC
Last modified on: 12/02/2024 18:15:08 UTC