CVEvulnerability

CVE-2020-8911

5.6 MEDIUM Published 2020-08-11 Modified 2026-06-17 Official page ↗
Status
Modified
Published
2020-08-11
Last modified
2026-06-17
Assigner
[email protected]
CVSS 3.1 ([email protected])
5.6 MEDIUM — CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N
CVSS 3.1 ([email protected])
5.6 MEDIUM — CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N
CVSS 2.0 ([email protected])
2.1 LOW — AV:L/AC:L/Au:N/C:P/I:N/A:N
Weaknesses
CWE-327

Description

A padding oracle vulnerability exists in the AWS S3 Crypto SDK for GoLang versions prior to V2. The SDK allows users to encrypt files with AES-CBC without computing a Message Authentication Code (MAC), which then allows an attacker who has write access to the target's S3 bucket and can observe whether or not an endpoint with access to the key can decrypt a file, they can reconstruct the plaintext with (on average) 128*length (plaintext) queries to the endpoint, by exploiting CBC's ability to manipulate the bytes of the next block and PKCS5 padding errors. It is recommended to update your SDK to V2 or later, and re-encrypt your files.

Affected configurations

• amazon aws s3 crypto sdk (< 2.0)

Related

Weakness · CWE (1)

  • CWE-327 Use of a Broken or Risky Cryptographic Algorithm weakness

References