CVE-2005-0626 in Squid
Summary
by MITRE
Race condition in Squid 2.5.STABLE7 to 2.5.STABLE9, when using the Netscape Set-Cookie recommendations for handling cookies in caches, may cause Set-Cookie headers to be sent to other users, which allows attackers to steal the related cookies.
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Analysis
by VulDB Data Team • 07/01/2019
The vulnerability identified as CVE-2005-0626 represents a critical race condition flaw within the Squid caching proxy server version 2.5.STABLE7 through 2.5.STABLE9. This issue specifically manifests when Squid implements the Netscape Set-Cookie recommendations for cookie handling in cache operations, creating a security weakness that enables unauthorized access to user session data. The vulnerability stems from improper synchronization mechanisms during concurrent cookie processing operations, allowing malicious actors to exploit temporal gaps in the system's cookie management procedures.
The technical implementation of this race condition occurs within Squid's cache handling mechanisms when multiple concurrent requests attempt to process Set-Cookie headers simultaneously. During these operations, the proxy server fails to properly lock or serialize access to shared cookie storage resources, creating opportunities for interleaved processing of cookie data. When multiple users make requests in rapid succession, the cache management system may incorrectly associate Set-Cookie headers with the wrong user sessions, effectively allowing one user's authentication tokens to be transmitted to another user's browser. This flaw operates at the application layer and specifically targets HTTP cookie handling functionality within the caching infrastructure.
The operational impact of this vulnerability extends beyond simple cookie leakage to represent a significant session hijacking risk that could compromise user authentication and authorization. Attackers exploiting this race condition can effectively steal session cookies from legitimate users, potentially gaining unauthorized access to web applications, personal accounts, and sensitive data. The vulnerability affects the fundamental security model of web caching systems by undermining the isolation between user sessions, particularly in environments where Squid serves as a shared proxy for multiple users. This issue directly violates security principles related to access control and session management, as defined in the OWASP Top Ten and other security frameworks.
Mitigation strategies for CVE-2005-0626 require immediate deployment of updated Squid versions that address the race condition in cookie handling operations. Organizations should upgrade to Squid versions beyond 2.5.STABLE9 where the race condition has been resolved through proper synchronization mechanisms and mutex locking for shared cookie resources. Additionally, system administrators should implement network-level controls to restrict access to vulnerable Squid instances and consider deploying additional authentication layers to detect and prevent unauthorized session access. The vulnerability aligns with CWE-362, which describes race conditions in concurrent programming, and represents a specific instance of information disclosure through improper resource management. Security monitoring should focus on detecting anomalous cookie behavior and unauthorized session access patterns, with controls aligned to ATT&CK technique T1566 for credential access through network sniffing and session hijacking. Organizations must also review their caching policies and implement proper session isolation measures to prevent similar vulnerabilities in other caching systems and web infrastructure components.