CVE-2021-39171 Explained : Impact and Mitigation

Passport-SAML, a SAML 2.0 authentication provider for Node.js, had a vulnerability allowing unlimited transforms for signed nodes prior to version 3.1.0.

Understanding CVE-2021-39171

A detailed overview of the vulnerability and its impact.

What is CVE-2021-39171?

Passport-SAML allowed unlimited transforms for signed nodes before version 3.1.0
Malicious SAML payloads could consume excessive system resources leading to denial-of-service
Resolved in version 3.1.0 by limiting allowable transforms to 2

The Impact of CVE-2021-39171

CVSS Score: 5.3 (Medium)
Attack Vector: Network
Attack Complexity: Low
Impact: Reduced service due to resource consumption
CWE ID: CWE-400: Uncontrolled Resource Consumption

Technical Details of CVE-2021-39171

Insight into the technical aspects of the vulnerability.

Vulnerability Description

Allows unlimited transforms pre-version 3.1.0
Excessive resource consumption could lead to denial-of-service

Affected Systems and Versions

Product: passport-saml
Vendor: node-saml
Affected Versions: < 3.1.0

Exploitation Mechanism

Malicious SAML payloads requiring multiple transforms
Consumption of significant system resources

Mitigation and Prevention

Measures to prevent and mitigate the impact of CVE-2021-39171.

Immediate Steps to Take

Upgrade to version 3.1.0 or later
Apply security patches promptly
Monitor system resources for unusual consumption

Long-Term Security Practices

Regularly update authentication libraries
Conduct security audits and testing
Implement rate limiting for system resources

Patching and Updates

Update to version 3.1.0 to limit allowable transforms to prevent resource exhaustion