Vulnerability in Amazon Aws S3 Crypto Sdk
CVE-2020-8911
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.
Vulnerability class: POODLE (CVE-2014-3566)
EPSS: 0.003 (27.4th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 5.6 (Medium). Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N.
Affected products
- Amazon Aws_s3_crypto_sdk
- Google Llc Aws S3 Crypto Sdk For Golang — versions stable
Weakness classification (CWE)
Public proof-of-concept exploits
References
- cve-coordination@google.com (x_refsource_CONFIRM, Vendor Advisory)
- cve-coordination@google.com (x_refsource_CONFIRM, Exploit, Third Party Advisory)
Frequently asked questions
- What is CVE-2020-8911?
- CVE-2020-8911 is a medium-severity vulnerability in Amazon Aws S3 Crypto Sdk, classified under Use of a Broken or Risky Cryptographic Algorithm. CVSS score: 5.6/10. Published 2020-08-11.
- How severe is CVE-2020-8911?
- Medium severity. CVSS v3 base score is 5.6 out of 10.
- Is CVE-2020-8911 known to be exploited?
- 10 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.