2.7 KiB
CVE-2023-4807
Description
Issue summary: The POLY1305 MAC (message authentication code) implementationcontains a bug that might corrupt the internal state of applications on theWindows 64 platform when running on newer X86_64 processors supporting theAVX512-IFMA instructions.Impact summary: If in an application that uses the OpenSSL library an attackercan influence whether the POLY1305 MAC algorithm is used, the applicationstate might be corrupted with various application dependent consequences.The POLY1305 MAC (message authentication code) implementation in OpenSSL doesnot save the contents of non-volatile XMM registers on Windows 64 platformwhen calculating the MAC of data larger than 64 bytes. Before returning tothe caller all the XMM registers are set to zero rather than restoring theirprevious content. The vulnerable code is used only on newer x86_64 processorssupporting the AVX512-IFMA instructions.The consequences of this kind of internal application state corruption canbe various - from no consequences, if the calling application does notdepend on the contents of non-volatile XMM registers at all, to the worstconsequences, where the attacker could get complete control of the applicationprocess. However given the contents of the registers are just zeroized sothe attacker cannot put arbitrary values inside, the most likely consequence,if any, would be an incorrect result of some application dependentcalculations or a crash leading to a denial of service.The POLY1305 MAC algorithm is most frequently used as part of theCHACHA20-POLY1305 AEAD (authenticated encryption with associated data)algorithm. The most common usage of this AEAD cipher is with TLS protocolversions 1.2 and 1.3 and a malicious client can influence whether this AEADcipher is used by the server. This implies that server applications usingOpenSSL can be potentially impacted. However we are currently not aware ofany concrete application that would be affected by this issue therefore weconsider this a Low severity security issue.As a workaround the AVX512-IFMA instructions support can be disabled atruntime by setting the environment variable OPENSSL_ia32cap: OPENSSL_ia32cap=:~0x200000The FIPS provider is not affected by this issue.
POC
Reference
No PoCs from references.