CVE-2016-1000236 in Node-cookie-signature
Summary
by MITRE
Node-cookie-signature before 1.0.6 is affected by a timing attack due to the type of comparison used.
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Analysis
by VulDB Data Team • 02/23/2024
The vulnerability identified as CVE-2016-1000236 affects the node-cookie-signature library version 1.0.5 and earlier, presenting a significant security risk through a timing attack vector. This flaw stems from the library's implementation of signature verification processes that do not employ constant-time comparison algorithms. The vulnerability allows attackers to exploit timing differences in the comparison operations to infer information about the cryptographic signatures, potentially leading to signature forgery and unauthorized access to cookie-based authentication mechanisms.
The technical flaw manifests in the use of standard string comparison operations rather than constant-time comparison functions during signature validation. When verifying cookie signatures, the library compares the computed signature against the expected value using operations that vary in execution time based on the position of the first mismatched character. This timing variation creates a side-channel attack surface that adversaries can leverage to perform statistical analysis and gradually reconstruct valid signatures through repeated requests. The vulnerability directly maps to CWE-203, which categorizes weaknesses related to information exposure through side channels, and specifically aligns with the timing attack class of vulnerabilities.
The operational impact of this vulnerability extends beyond simple authentication bypasses, as it compromises the integrity of cookie-based session management systems. Attackers can exploit this weakness to forge authentication cookies, potentially gaining unauthorized access to user sessions, performing privilege escalation attacks, or conducting session hijacking operations. The attack requires minimal resources and can be automated, making it particularly dangerous in environments where cookie-based authentication is prevalent. This vulnerability affects web applications that rely on node-cookie-signature for secure cookie handling, potentially impacting thousands of applications across various organizations.
Mitigation strategies for this vulnerability include immediate upgrading to node-cookie-signature version 1.0.6 or later, which implements proper constant-time comparison algorithms. Organizations should also review their cookie handling implementations and consider additional security measures such as implementing additional authentication factors, using more robust session management techniques, and conducting regular security assessments of their authentication systems. The fix addresses the core issue by replacing the vulnerable comparison logic with constant-time algorithms that ensure identical execution times regardless of input differences, preventing the timing side-channel that enabled the attack. This remediation aligns with best practices recommended in the OWASP Top Ten and follows the ATT&CK framework's mitigation strategies for credential access and defense evasion techniques that rely on timing-based information leakage.