GitHub Advisoryadvisory · npm
GHSA-94hh-pjjg-rwmr Padding Oracle Attack due to Observable Timing Discrepancy in jose-browser-runtime
MEDIUM
Official page ↗
- Aliases
- CVE-2021-29444
- Ecosystem
- npm
- Packages
- jose-browser-runtime
- Severity
- Moderate
- CVSS vector
- CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
- Weaknesses
- CWE-203
- Reviewed
- 2021-04-16
Affected packages
• npm jose-browser-runtime: < 3.11.4 → fixed in 3.11.4
Description
Impact
AES_CBC_HMAC_SHA2 Algorithm (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
A patch was released which ensures the HMAC tag is verified before performing CBC decryption. The fixed versions are `>=3.11.4`.
Users should upgrade to `^3.11.4`.
Credits
Thanks to Morgan Brown of Microsoft for bringing this up and Eva Sarafianou (@esarafianou) for helping to score this advisory.
Related
Alias · CVE (1)
- CVE-2021-29444 jose-browser-runtime is an npm package which provides a number of cryptographic functions. vulnerability
Weakness · CWE (1)
- CWE-203 Observable Discrepancy weakness