Advisories for Pypi/Jwcrypto package

2024

JWCrypto vulnerable to JWT bomb Attack in `deserialize` function

Affected version Vendor: https://github.com/latchset/jwcrypto Version: 1.5.5 Description An attacker can cause a DoS attack by passing in a malicious JWE Token with a high compression ratio. When the server processes this Token, it will consume a lot of memory and processing time. Poc from jwcrypto import jwk, jwe from jwcrypto.common import json_encode, json_decode import time public_key = jwk.JWK() private_key = jwk.JWK.generate(kty='RSA', size=2048) public_key.import_key(**json_decode(private_key.export_public())) payload = '{"u": "' + "u" * …

2023
2022

jwcrypto token substitution can lead to authentication bypass

The JWT code can auto-detect the type of token being provided, and this can lead the application to incorrect conclusions about the trustworthiness of the token. Quoting the private disclosure we received : "Under certain circumstances, it is possible to substitute a [..] signed JWS with a JWE that is encrypted with the public key that is normally used for signature validation." This substitution attack can occur only if the …