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.
CVE-2020-8911 - Medium Severity Vulnerability
AWS SDK for the Go programming language.
Dependency Hierarchy: - :x: **github.com/aws/aws-sdk-go-v1.31.4** (Vulnerable Library)
Found in HEAD commit: 3ad3fc12dc1fbb1d1917f3fc53146d54a3484b59
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.
Publish Date: 2020-08-11
URL: CVE-2020-8911
Base Score Metrics: - Exploitability Metrics: - Attack Vector: Local - Attack Complexity: High - Privileges Required: Low - User Interaction: None - Scope: Changed - Impact Metrics: - Confidentiality Impact: High - Integrity Impact: None - Availability Impact: None
For more information on CVSS3 Scores, click here.Type: Upgrade version
Origin: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-8911
Release Date: 2020-07-21
Fix Resolution: v1.34.1
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