CVE-2023-6258 in pkcs11-provider
Summary
by MITRE • 01/30/2024
A security vulnerability has been identified in the pkcs11-provider, which is associated with Public-Key Cryptography Standards (PKCS#11). If exploited successfully, this vulnerability could result in a Bleichenbacher-like security flaw, potentially enabling a side-channel attack on PKCS#1 1.5 decryption.
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Analysis
by VulDB Data Team • 05/09/2026
The pkcs11-provider vulnerability represents a critical security weakness within the Public-Key Cryptography Standards infrastructure that could enable sophisticated cryptographic attacks. This flaw specifically relates to the implementation of PKCS#1 1.5 decryption mechanisms, which are widely used in cryptographic operations across various security systems. The vulnerability's potential to create a Bleichenbacher-like flaw indicates a serious concern for cryptographic security, as such attacks have been previously documented in the cryptographic community and represent well-known attack vectors against RSA encryption schemes. The PKCS#1 1.5 padding scheme has historically been susceptible to timing and side-channel attacks that can reveal information about the encrypted data, making this particular vulnerability especially dangerous for systems relying on this standard.
The technical implementation flaw within the pkcs11-provider stems from inadequate handling of cryptographic operations that could expose timing variations or other side-channel information during the decryption process. When a system processes PKCS#1 1.5 padded data, proper constant-time execution is essential to prevent attackers from inferring information about the plaintext through timing analysis. The vulnerability likely manifests in the way the provider handles error conditions or validation checks during decryption operations, creating observable differences in execution time or resource usage that can be exploited by attackers. This weakness creates opportunities for adversaries to perform statistical analysis on timing data to gradually reconstruct the original plaintext, particularly when the target system uses RSA encryption with PKCS#1 1.5 padding. The implementation may not properly mask timing variations that occur during modular exponentiation or other cryptographic operations, leading to information leakage that compromises the security of the entire system.
The operational impact of this vulnerability extends beyond simple cryptographic weakness to potentially compromise entire security infrastructures that depend on PKCS#1 1.5 encryption. Systems utilizing this provider could face significant risks including unauthorized data access, key compromise, and potential full system breaches when attackers successfully exploit the side-channel vulnerabilities. The attack surface is particularly concerning for environments where the pkcs11-provider is used in high-security applications such as secure key storage, digital signature verification, and secure communications protocols. Organizations relying on this cryptographic provider for protecting sensitive data, authentication tokens, or secure communications may experience cascading security failures if the vulnerability is exploited successfully. The Bleichenbacher-like nature of the flaw means that attackers could potentially perform multiple decryption attempts and use the timing variations to recover the original plaintext, making this vulnerability particularly dangerous for systems where the same encryption keys are used repeatedly or where attackers can perform multiple attack attempts.
Mitigation strategies for this vulnerability should focus on implementing proper constant-time cryptographic operations and eliminating timing variations in the decryption process. The primary recommendation involves updating the pkcs11-provider to versions that properly handle PKCS#1 1.5 padding without exposing timing information, which aligns with the principles outlined in the CWE-204 standard for timing attack prevention. Organizations should also consider implementing additional security measures such as random delays or constant-time implementations for all cryptographic operations that could potentially leak information through side channels. The ATT&CK framework categorizes this type of vulnerability under the T1059.001 technique for "Command and Scripting Interpreter" when attackers leverage such weaknesses to perform cryptographic attacks, making proper patching and monitoring essential. Security teams should conduct thorough vulnerability assessments to identify all systems using the affected provider and implement comprehensive monitoring for potential side-channel attack indicators. The remediation process should also include reviewing and updating cryptographic protocols to move away from vulnerable PKCS#1 1.5 padding schemes toward more secure alternatives such as OAEP padding, which provides better resistance against timing attacks and other side-channel vulnerabilities that have been documented in cryptographic literature and industry standards.