CVE-2013-10031 in Plack::Middleware::Session
Summary
by MITRE • 12/09/2025
Plack-Middleware-Session versions before 0.17 may be vulnerable to HMAC comparison timing attacks
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Analysis
by VulDB Data Team • 12/16/2025
The vulnerability identified as CVE-2013-10031 affects Plack-Middleware-Session versions prior to 017, exposing applications to HMAC comparison timing attacks that can compromise session security. This flaw resides in the session management component of web applications built on the Plack framework, which serves as a common interface for perl web applications and middleware components. The issue specifically manifests during the verification of HMAC signatures used to authenticate session data, creating a potential avenue for attackers to exploit timing differences in cryptographic comparisons.
The technical implementation flaw stems from the use of a non-constant time HMAC comparison function within the session middleware. When comparing HMAC signatures, the vulnerable code performs a byte-by-byte comparison that reveals timing information about the authentication process. Attackers can leverage this timing variation to perform side-channel analysis and gradually deduce the correct HMAC value through multiple request attempts. This timing attack approach aligns with the common pattern described in CWE-327, which addresses the use of insecure cryptographic algorithms and improper implementation of cryptographic functions.
The operational impact of this vulnerability extends beyond simple session hijacking, as it can lead to complete application compromise when combined with other attack vectors. An attacker who successfully exploits this timing vulnerability can gain unauthorized access to user sessions, potentially escalating privileges and accessing sensitive data. The attack requires minimal resources and can be automated, making it particularly dangerous in environments where session management is critical for application security. This vulnerability directly impacts the integrity and confidentiality aspects of the CIA triad, as it undermines the cryptographic protection mechanisms designed to secure session data.
Mitigation strategies for CVE-2013-10031 involve immediate upgrading to Plack-Middleware-Session version 0.17 or later, which implements constant-time HMAC comparison functions. Organizations should also conduct comprehensive security assessments of their web applications to identify any other components that might be susceptible to similar timing attacks. The fix addresses the underlying issue by ensuring that HMAC comparisons take constant time regardless of input values, eliminating the timing information that attackers could exploit. This remediation aligns with best practices recommended in the OWASP Top Ten and follows the ATT&CK framework's mitigation strategies for cryptographic attacks, specifically targeting techniques related to timing side-channel vulnerabilities. System administrators should also implement monitoring for unusual authentication patterns and consider additional security layers such as rate limiting and multi-factor authentication to further protect against exploitation attempts.