bc-csharp: AES-CCM decryption accepts zero or out-of-range tag length, bypassing authentication
What fixes it
- 2.7.0bc-csharpCVE List
A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.
Description
Improper validation of integrity check value in the AES-CCM implementation (CcmParameters and CcmBlockCipher) in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows an on-path attacker to modify CCM-encrypted content without detection via an AlgorithmIdentifier whose CCMParameters declare an authentication tag (aes-ICVlen) of zero or another length outside the RFC 5084 set, because CcmParameters accepted any value and CcmBlockCipher validated the tag length only when encrypting, so decryption compared a zero-length or very short tag. Affected paths include ParameterUtilities.GetCipherParameters, used by CmsEnvelopedData and CmsEnvelopedDataParser for EnvelopedData encrypted with AES-CCM, and any caller passing an unchecked tag length to CcmBlockCipher for decryption.
Text from CVE List
Affected versions 1
- bc-csharpaffected: all versions before 2.7.0CVE List