Vulnerability · Published Apr 16, 2021 · Assigned by GitHub_M

CVE-2021-29443Padding Oracle Attack due to Observable Timing Discrepancy in jose

Medium 5.9

In plain English

A medium-severity security flaw in jose from panva. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.2% (higher than 67% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)5.9Medium
Exploit odds (30 days)1.2%top 32.5% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known

Official description

jose is an npm library providing a number of cryptographic operations. In vulnerable versions 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. 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). 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, their v2.x dependency to ^2.0.5, and their v3.x dependency to ^3.11.4. Thanks to Jason from Microsoft Vulnerability Research (MSVR) for bringing this up and Eva Sarafianou (@esarafianou) for helping to score this advisory.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
npmjose1.28.1GHSA-58f5-hfqc-jgch
npmjose2.0.5GHSA-58f5-hfqc-jgch
npmjose3.11.4GHSA-58f5-hfqc-jgch

Affected products (as reported)

VendorProductVersions
panva jose < 1.28.1>= 2.0.0, < 2.0.5>= 3.0.0, < 3.11.4

Weakness: CWE-203 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

References