aws-encryption-sdk@4.0.3

aws-encryption-sdk is an AWS Encryption SDK implementation for Python

Affected versions of this package are vulnerable to Selection of Less-Secure Algorithm During Negotiation ('Algorithm Downgrade') via the shared key cache. An attacker can bypass key commitment policy enforcement by exploiting the caching mechanism, potentially causing ciphertext to be decrypted into multiple different plaintexts.

Note:

This is only exploitable if all of the following conditions are met:

• Two ESDK for Python clients with different commitment policies share a single CachingCryptoMaterialsManager instance within the same process;

• The client with the weaker commitment policy encrypts first, warming the cache;

• Both clients use matching encryption contexts;

• Both clients use the pre-configured default algorithm suite.

Upgrade aws-encryption-sdk to version 3.3.1, 4.0.5 or higher.