Executive Summary

This vulnerability exists in openCryptoki, a PKCS#11 library used on Linux and AIX systems. In versions 3.26.0 and below, the BER/DER decoding functions in the shared library accept a raw pointer without a buffer length parameter and trust attacker-controlled BER length fields without validating them against actual buffer boundaries.

All primitive decoders such as ber_decode_INTEGER, ber_decode_SEQUENCE, ber_decode_OCTET_STRING, ber_decode_BIT_STRING, and ber_decode_CHOICE are affected. Specifically, ber_decode_INTEGER can cause integer underflows when the encoded length is zero.

An attacker can supply malformed BER-encoded cryptographic objects through PKCS#11 operations like C_CreateObject or C_UnwrapKey, token loading from disk, or remote backend communication to trigger out-of-bounds reads. This affects all token backends because the vulnerable code is in the shared common library.

Useful 0 Not Useful 0

Impact Analysis

The vulnerability can lead to out-of-bounds reads when processing malformed BER-encoded cryptographic objects. This can cause application crashes or potentially expose sensitive memory contents.

The CVSS score of 6.8 indicates a medium severity impact with local attack vector, low attack complexity, no privileges required, no user interaction, unchanged scope, low confidentiality impact, no integrity impact, and high availability impact.

Therefore, the main impact is denial of service or information disclosure through memory exposure, which can affect the availability and confidentiality of cryptographic operations.

Useful 0 Not Useful 0

Mitigation Strategies

To mitigate this vulnerability, apply the available patch provided through commit ed378f463ef73364c89feb0fc923f4dc867332a3 to update openCryptoki to a version above 3.26.0.

Since the vulnerability affects all token backends due to shared library code, ensure that all instances of openCryptoki on your systems are updated.

Useful 0 Not Useful 0