CVE-2024-5699 in Firefox
Summary
by MITRE • 06/11/2024
In violation of spec, cookie prefixes such as `__Secure` were being ignored if they were not correctly capitalized - by spec they should be checked with a case-insensitive comparison. This could have resulted in the browser not correctly honoring the behaviors specified by the prefix. This vulnerability affects Firefox < 127.
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Analysis
by VulDB Data Team • 03/24/2025
This vulnerability relates to the improper implementation of cookie prefix validation in Firefox browsers, specifically concerning the `__Secure` prefix which is defined in the cookie specification. The issue stems from a deviation from the established web standards where cookie prefixes must be validated using case-insensitive comparison rather than strict case-sensitive matching. According to the cookie specification, prefixes like `__Secure` should be recognized regardless of their capitalization to ensure consistent behavior across different implementations and prevent potential security bypasses.
The technical flaw manifests when Firefox encounters cookies with the `__Secure` prefix that are not correctly capitalized, such as `__secure` or `__SECURE`. The browser fails to recognize these cookies as requiring special security handling, which means that cookies intended to be secure and restricted to HTTPS connections may be processed in a manner that violates their security design. This behavior creates a potential security gap where cookies that should only be transmitted over secure connections could be sent over unencrypted channels, undermining the intended security posture of web applications that rely on these cookie prefixes for proper security enforcement.
The operational impact of this vulnerability is significant for users of affected Firefox versions, as it could lead to the exposure of sensitive information through cookie transmission over insecure channels. When cookies with the `__Secure` prefix are not properly validated, web applications may inadvertently expose authentication tokens, session identifiers, or other sensitive data that should remain protected within secure contexts. This issue particularly affects applications that depend on strict cookie security policies to maintain user sessions and protect against session hijacking or cross-site scripting attacks that could exploit the improper cookie handling behavior.
This vulnerability aligns with CWE-295, which addresses improper certificate validation, and represents a failure to properly implement security controls that should be enforced by the browser. From an ATT&CK perspective, this issue could facilitate techniques such as credential access through network sniffing or session hijacking, as the proper security boundaries for cookie transmission are not being maintained. The vulnerability also relates to CWE-611, which covers improper access control in web applications, as the failure to properly validate cookie prefixes can result in unauthorized access to sensitive session data. The affected Firefox versions prior to 127 represent a window where users were exposed to potential security risks due to the browser's non-compliance with established cookie handling specifications, making it essential for users to update to patched versions to maintain proper security posture and prevent potential exploitation by malicious actors who might target this implementation gap.