CVE-2020-8912 Information

Description

A vulnerability in the in-band key negotiation exists in the AWS S3 Crypto SDK for GoLang versions prior to V2. An attacker with write access to the targeted bucket can change the encryption algorithm of an object in the bucket which can then allow them to change AES-GCM to AES-CTR. Using this in combination with a decryption oracle can reveal the authentication key used by AES-GCM as decrypting the GMAC tag leaves the authentication key recoverable as an algebraic equation. It is recommended to update your SDK to V2 or later and re-encrypt your files.

CVSS Vector

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

Reference

https://aws.amazon.com/blogs/developer/updates-to-the-amazon-s3-encryption-client/?s=09 https://github.com/google/security-research/security/advisories/GHSA-7f33-f4f5-xwgw

Attack Complexity

HIGH

Privileges Required

LOW

User Interaction Required

LOW

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

LOW

Availability Impact

NONE

Base Score

NONE

Base Severity

2.5