CVE-2014-8684 in CodeIgniter
Summary
by MITRE
CodeIgniter before 3.0 and Kohana 3.2.3 and earlier and 3.3.x through 3.3.2 make it easier for remote attackers to spoof session cookies and consequently conduct PHP object injection attacks by leveraging use of standard string comparison operators to compare cryptographic hashes.
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Analysis
by VulDB Data Team • 01/10/2025
The vulnerability identified as CVE-2014-8684 represents a critical security flaw affecting popular PHP web frameworks including CodeIgniter versions prior to 3.0 and Kohana versions 3.2.3 and earlier as well as 3.3.x through 3.3.2. This weakness stems from the improper handling of cryptographic hash comparisons within session management mechanisms, creating opportunities for sophisticated attack vectors that can compromise application security. The vulnerability falls under the category of weak cryptographic comparisons and specifically relates to timing attacks that exploit the use of standard string comparison operators instead of constant-time comparison functions.
The technical flaw manifests when applications use standard equality operators such as == or === for comparing cryptographic hashes in session cookie validation processes. This approach creates a timing side-channel vulnerability that allows attackers to perform statistical analysis on response times to determine the correct hash values. The implementation uses a simple string comparison rather than a constant-time comparison function, enabling attackers to gradually reconstruct session identifiers through repeated requests and timing observations. This weakness directly maps to CWE-208, which addresses timing attacks, and CWE-310, which covers cryptographic issues related to weak randomness and improper comparison functions. The vulnerability enables attackers to craft malicious session cookies that can bypass authentication mechanisms and potentially execute arbitrary code through PHP object injection attacks.
The operational impact of this vulnerability extends beyond simple session hijacking to encompass more severe consequences including unauthorized access to protected resources, privilege escalation, and potential full system compromise. Attackers can exploit this weakness to impersonate legitimate users, access sensitive data, and perform actions within the application context that should be restricted to authorized personnel. The vulnerability particularly affects web applications that rely on session-based authentication and are vulnerable to PHP object injection attacks when session cookies are successfully spoofed. This creates a pathway for attackers to leverage the session spoofing capability to execute malicious code within the application environment, potentially leading to complete system compromise.
Mitigation strategies for this vulnerability require immediate framework upgrades to versions that implement proper cryptographic hash comparison functions. Organizations should ensure all affected CodeIgniter and Kohana installations are updated to their latest secure versions, which typically include constant-time comparison functions such as hash_equals() in PHP 5.6 and later. Additionally, security teams should implement proper session management practices including secure cookie attributes, HTTPS enforcement, and regular security audits. The remediation process should also include monitoring for potential exploitation attempts and implementing intrusion detection systems that can identify timing-based attack patterns. This vulnerability demonstrates the critical importance of following secure coding practices and adhering to established security standards including those outlined in the OWASP Top Ten and NIST guidelines for cryptographic implementation. Organizations should also consider implementing additional security layers such as web application firewalls and session token randomization techniques to further reduce the attack surface.