CVE-2016-15005 in golf
Summary
by MITRE • 12/28/2022
CSRF tokens are generated using math/rand, which is not a cryptographically secure rander number generation, making predicting their values relatively trivial and allowing an attacker to bypass CSRF protections which relatively few requests.
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Analysis
by VulDB Data Team • 04/11/2025
The vulnerability identified as CVE-2016-15005 represents a critical weakness in web application security mechanisms that directly impacts the integrity of cross-site request forgery protection systems. This flaw resides in the token generation process where applications rely on the math/rand package for creating CSRF tokens, a choice that fundamentally undermines the security posture of the affected systems. The mathematical random number generator used in this context lacks the cryptographic properties necessary to produce unpredictable values, creating a significant attack surface that malicious actors can exploit to bypass essential security controls.
The technical implementation of this vulnerability stems from the fundamental difference between pseudo-random number generators and cryptographically secure random number generators. The math/rand package in go programming language generates numbers using a deterministic algorithm that produces sequences of numbers that appear random but are actually predictable given sufficient information about the seed value and the algorithm itself. This characteristic makes it unsuitable for security-sensitive applications where unpredictability is paramount. When CSRF tokens are generated using such insecure random number generators, the tokens lose their effectiveness as security controls because attackers can potentially reconstruct the sequence of random values and generate valid tokens for unauthorized actions.
The operational impact of this vulnerability extends beyond simple bypass of CSRF protections to encompass broader security implications for web applications that depend on token-based authentication mechanisms. An attacker who successfully predicts or generates valid CSRF tokens can perform authenticated actions on behalf of legitimate users without their knowledge or consent. This capability allows for session hijacking, privilege escalation, and data manipulation attacks that can compromise user accounts and sensitive system information. The vulnerability is particularly concerning because it affects relatively few requests, meaning that even limited attack windows can provide sufficient opportunities for exploitation. The predictability of tokens means that attackers can potentially automate their attacks, making this vulnerability particularly dangerous in environments with high user traffic and frequent authentication requests.
Organizations implementing applications that use insecure random number generators for CSRF token creation face significant risks including unauthorized access to user accounts, data breaches, and potential compliance violations with security standards such as the Payment Card Industry Data Security Standard and the General Data Protection Regulation. The vulnerability directly relates to CWE-330, which identifies the use of insufficiently random values in security contexts, and aligns with ATT&CK technique T1566, which covers social engineering attacks that exploit predictable security mechanisms. Effective mitigation strategies must include replacing insecure random number generators with cryptographically secure alternatives such as crypto/rand, implementing proper entropy sources, and conducting comprehensive security testing to identify similar vulnerabilities in other security controls. Additionally, organizations should establish security coding practices that mandate the use of appropriate cryptographic libraries for security-sensitive operations and implement regular vulnerability assessments to detect and remediate similar weaknesses in their application portfolios.