CVE-2023-40660 in OpenSC
Summary
by MITRE • 11/06/2023
A flaw was found in OpenSC packages that allow a potential PIN bypass. When a token/card is authenticated by one process, it can perform cryptographic operations in other processes when an empty zero-length pin is passed. This issue poses a security risk, particularly for OS logon/screen unlock and for small, permanently connected tokens to computers. Additionally, the token can internally track login status. This flaw allows an attacker to gain unauthorized access, carry out malicious actions, or compromise the system without the user's awareness.
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Analysis
by VulDB Data Team • 12/28/2024
The vulnerability identified as CVE-2023-40660 represents a critical security flaw within OpenSC packages that enables unauthorized PIN bypass capabilities across multiple processes. This issue fundamentally undermines the authentication mechanisms designed to protect cryptographic tokens and smart cards, creating a persistent security risk that extends beyond traditional boundary limitations. The flaw specifically affects how authentication states are managed and propagated between different processes, allowing an attacker to exploit the system's trust model through a simple empty zero-length PIN parameter. This vulnerability operates at the core of token authentication architecture, where the system fails to properly validate authentication contexts when transitioning between processes, effectively creating a backdoor that bypasses normal security controls.
The technical implementation of this vulnerability stems from improper handling of authentication state persistence across process boundaries within the OpenSC framework. When a token is authenticated by one process, the system maintains an internal login status that should normally require explicit authentication for subsequent operations. However, the flaw allows any process to utilize the token's cryptographic capabilities without proper PIN validation when an empty PIN is provided, effectively creating a race condition or state management error. This behavior violates fundamental security principles of process isolation and authentication verification, as the system fails to enforce proper access controls when transitioning from one process context to another. The vulnerability specifically impacts how the system handles zero-length PIN parameters, treating them as valid authentication credentials rather than rejecting them as invalid input.
The operational impact of this vulnerability extends significantly beyond simple unauthorized access, creating opportunities for sophisticated attacks that could compromise entire systems. For operating system logon and screen unlock scenarios, this flaw allows attackers to bypass authentication mechanisms entirely, potentially enabling full system compromise without user knowledge or consent. The risk is particularly elevated for permanently connected tokens that remain authenticated, as these devices become persistent attack vectors that can be exploited by malicious processes running with appropriate privileges. Additionally, the vulnerability's ability to operate silently means that system administrators may not detect unauthorized activities, creating a stealthy threat that can persist undetected for extended periods. This characteristic aligns with attack patterns described in the ATT&CK framework under credential access and privilege escalation techniques, where attackers leverage system weaknesses to maintain persistent access.
Security implications of CVE-2023-40660 are particularly severe when considering the broader threat landscape and potential exploitation vectors. The vulnerability creates opportunities for attackers to perform cryptographic operations without proper authorization, potentially enabling man-in-the-middle attacks, data exfiltration, or system compromise through the exploitation of trusted token relationships. Organizations using OpenSC for security-critical applications face significant exposure, particularly in environments where tokens are used for authentication, digital signatures, or encryption operations. The flaw's persistence across process boundaries means that even when individual applications terminate, the authenticated state remains available to other processes, creating a continuous threat surface that traditional security controls may not adequately address. This vulnerability directly relates to CWE-284, which addresses improper access control, and represents a classic example of inadequate privilege management within multi-process security architectures. Mitigation strategies should include immediate patch deployment, process monitoring for unauthorized token usage, and implementation of additional access control layers to prevent exploitation of the authentication bypass mechanism.