CVE-2024-45337 in x-crypto
Summary
by MITRE • 12/12/2024
Applications and libraries which misuse the ServerConfig.PublicKeyCallback callback may be susceptible to an authorization bypass.
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Analysis
by VulDB Data Team • 06/20/2026
The vulnerability identified as CVE-2024-45337 represents a critical authorization flaw that can be exploited through improper implementation of the ServerConfig.PublicKeyCallback mechanism in cryptographic applications. This callback function is typically employed in secure communication protocols to validate public keys during authentication processes, making it a crucial component in maintaining system integrity. When applications fail to properly validate or sanitize inputs within this callback, they create opportunities for malicious actors to bypass authentication mechanisms entirely. The flaw specifically manifests when developers assume that the callback will automatically enforce proper authorization checks, while in reality the callback may be invoked in contexts where security validation is insufficient or completely absent.
The technical root cause of this vulnerability stems from inadequate input validation and improper security boundary enforcement within the callback implementation. According to CWE-284, this issue falls under improper access control, where the system fails to properly restrict access to resources based on the authentication state of the user. The ServerConfig.PublicKeyCallback mechanism is designed to provide a hook for custom public key validation logic, but when misused, it can become a vector for privilege escalation. Attackers can exploit this by crafting specific inputs that cause the callback to either skip validation entirely or return false positive results, effectively allowing unauthorized access to protected resources.
The operational impact of CVE-2024-45337 extends beyond simple unauthorized access, potentially enabling full system compromise when the vulnerable applications handle sensitive data or critical infrastructure functions. This vulnerability aligns with ATT&CK technique T1078.004, which covers valid accounts used for lateral movement, as unauthorized access through compromised authentication mechanisms can provide attackers with persistent access to systems. Organizations running applications that utilize this callback mechanism may experience data breaches, system infiltration, and unauthorized privilege escalation. The vulnerability is particularly concerning in environments where SSH servers or similar cryptographic protocols are deployed, as these systems often serve as entry points for broader network infiltration attempts.
Mitigation strategies for CVE-2024-45337 require comprehensive code review and implementation of proper validation mechanisms within the ServerConfig.PublicKeyCallback. Organizations should ensure that all callback implementations enforce strict validation of public key parameters and reject any input that does not meet predefined security criteria. The fix involves implementing robust input sanitization and ensuring that the callback function properly validates the authenticity of public keys before granting access. Additionally, developers should follow secure coding practices as outlined in OWASP Top Ten and NIST guidelines, particularly focusing on authentication and access control validation. Regular security audits and penetration testing should be conducted to identify similar misconfigurations in other callback mechanisms throughout the application stack. The vulnerability demonstrates the critical importance of proper cryptographic implementation and the need for thorough security testing of authentication components in networked applications.