Padding Oracle Attack due to Observable Timing Discrepancy in jose-node-esm-runtime

中 5.9CVE-2021-29445 · GHSA-4v4g-726h-xvfv · 16/04/2021 公開 · 17/06/2026 更新

要点

CVE-2021-29445 は jose-node-cjs-runtime (jose-node-cjs-runtime project), jose-node-esm-runtime に影響する深刻度「中」 (CVSS 5.9) の脆弱性です。
今後30日間に悪用される確率（EPSS）：1.1%（全脆弱性の 64.9% より高い）。
対処：3.11.4 以降に更新してください。

パッケージ	影響を受けるバージョン	修正済みバージョン
jose-node-cjs-runtime jose-node-cjs-runtime_project	`< 3.11.4`	`3.11.4`
jose-node-esm-runtime npm	`< 3.11.4`	`3.11.4`

概要

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.

NVD の説明

jose-node-esm-runtime is an npm package which provides a number of cryptographic functions. In versions prior to 3.11.4 the 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). 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`.