CVE-2015-9238 in secure-compare
Summary
by MITRE
secure-compare 3.0.0 and below do not actually compare two strings properly. compare was actually comparing the first argument with itself, meaning the check passed for any two strings of the same length.
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Analysis
by VulDB Data Team • 03/17/2023
The vulnerability identified as CVE-2015-9238 affects the secure-compare npm package version 3.0.0 and earlier, representing a critical security flaw in cryptographic string comparison operations. This issue stems from a fundamental implementation error where the comparison function fails to properly evaluate two distinct input strings, instead performing a comparison of the first argument against itself. The flaw fundamentally undermines the security assurances that cryptographic string comparisons are designed to provide, creating a scenario where authentication mechanisms and security checks can be bypassed through simple length-based attacks.
The technical root cause of this vulnerability lies in the improper implementation of the compare function within the secure-compare library. When developers utilize this library for security-sensitive operations such as password verification, token validation, or authentication checks, the function incorrectly processes inputs by comparing the first parameter with itself rather than comparing the two distinct parameters provided. This misimplementation creates a condition where the function will return a successful match result whenever two strings share identical length characteristics, regardless of their actual content. The vulnerability manifests as a timing attack surface where attackers can exploit the predictable behavior to bypass security controls without needing to know the actual string values.
From an operational perspective, this vulnerability presents significant risks to applications that depend on the secure-compare library for authentication and validation processes. The impact extends beyond simple authentication bypasses to encompass any security mechanism that relies on string comparison for access control, session management, or cryptographic verification. The flaw effectively renders the security checks meaningless for inputs of the same length, creating a false sense of security that could be exploited by attackers to gain unauthorized access to systems or bypass critical security controls. This vulnerability is particularly dangerous in environments where password verification, API token validation, or cryptographic key comparisons occur, as it allows attackers to pass validation checks without knowing the correct values.
The vulnerability aligns with CWE-20, which addresses improper input validation, and specifically relates to CWE-310, which covers cryptographic issues including weak cryptographic primitives and improper implementation of security functions. From an ATT&CK framework perspective, this vulnerability maps to techniques involving credential access through bypassing authentication mechanisms and privilege escalation by exploiting weak security controls. The flaw represents a failure in the secure coding practices that should be enforced during the development of cryptographic libraries, where proper validation and implementation of security functions are paramount to maintaining system integrity.
Mitigation strategies for CVE-2015-9238 require immediate action to upgrade to version 3.0.1 or later of the secure-compare package where the implementation error has been corrected. Organizations should conduct comprehensive audits of their codebases to identify all instances where this library is utilized, particularly in authentication flows, password verification systems, and cryptographic operations. Security teams should implement automated scanning tools to detect usage of vulnerable library versions and establish processes for regular dependency updates. Additionally, developers should consider implementing redundant security checks and alternative validation mechanisms as defensive measures while transitioning to patched versions. The vulnerability underscores the critical importance of thorough testing and validation of cryptographic functions, particularly when dealing with authentication and authorization controls that are fundamental to system security.