Padding Oracle Attack due to Observable Timing Discrepancy in jose
jose is an npm library providing a number of cryptographic operations.
### Impact
AES_CBC_HMAC_SHA2 Algorithm
https://tools.ietf.org/html/rfc7518#section-5.2 (A128CBC-HS256, A192CBC-HS384, A256CBC-HS512) decryption would always execute both HMAC tag verification and CBC decryption, if either failed `JWEDecryptionFailed` would be thrown. But a possibly observable difference in timing when padding error would occur while decrypting the ciphertext makes a padding oracle and an adversary might be able to make use of that oracle to decrypt data without knowing the decryption key by issuing on average 128*b calls to the padding oracle (where b is the number of bytes in the ciphertext block).
### Patches
All major release versions have had a patch released which ensures the HMAC tag is verified before performing CBC decryption. The fixed versions are `^1.28.1 || ^2.0.5 || >=3.11.4`.
Users should upgrade their v1.x dependency to `^1.28.1`
https://github.com/panva/jose/releases/tag/v1.28.1, their v2.x dependency to `^2.0.5`
https://github.com/panva/jose/releases/tag/v2.0.5, and their v3.x dependency to `^3.11.4`
https://github.com/panva/jose/releases/tag/v3.11.4
### Credits
Thanks to Morgan Brown of Microsoft for bringing this up and Eva Sarafianou (@esarafianou) for helping to score this advisory.