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

2021-04-1617:35:12

CWE-203

GitHub_M

www.cve.org

5.9 Medium

CVSS3

Attack Vector

NETWORK

Attack Complexity

HIGH

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

NONE

Availability Impact

NONE

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

5.9 Medium

AI Score

Confidence

High

0.001 Low

EPSS

Percentile

51.3%

JSON

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.

CNA Affected

[
  {
    "product": "jose",
    "vendor": "panva",
    "versions": [
      {
        "status": "affected",
        "version": "< 1.28.1"
      },
      {
        "status": "affected",
        "version": ">= 2.0.0, < 2.0.5"
      },
      {
        "status": "affected",
        "version": ">= 3.0.0, < 3.11.4"
      }
    ]
  }
]