CVE-2020-8911

CBC padding oracle in AWS S3 Crypto SDK for GoLang

Published Aug 11, 2020 CVSS 3.1 · 5.6 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
EUVD EUVD EUVD-2022-0971 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.
Github GHSA Github GHSA GHSA-f5pg-7wfw-84q9 CBC padding oracle issue in AWS S3 Crypto SDK for golang
History
Type Values Removed Values Added
Metrics epss

{'score': 0.00203}

epss

{'score': 0.00209}

Weaknesses

Sources

Status
PUBLISHED
Assigner
Google
Published
Updated
Aug 4, 2024, 10:12 AM
Reserved
Feb 12, 2020, 12:00 AM
Status
Modified
Published
Aug 11, 2020, 8:15 PM
Modified
Jun 17, 2026, 3:27 AM
Severity
Moderate
Public date
Aug 11, 2020, 12:00 AM