CVE-2020-5268 : Security Advisory and Response

In Saml2 Authentication Services for ASP.NET versions before 1.0.2, and between 2.0.0 and 2.6.0, a vulnerability exists in how tokens are validated, potentially allowing attackers to create a login session.

Understanding CVE-2020-5268

This CVE involves a vulnerability in the validation of Saml2 tokens in ASP.NET.

What is CVE-2020-5268?

The vulnerability arises from the incorrect treatment of incoming tokens as bearer tokens, even when another subject confirmation method is specified in the Saml2 protocol.

The Impact of CVE-2020-5268

CVSS Base Score: 6.5 (Medium Severity)
Attack Vector: Network
Confidentiality Impact: High
Integrity Impact: Low
Privileges Required: Low
User Interaction: Required
Scope: Changed
Attack Complexity: High
Availability Impact: None

Technical Details of CVE-2020-5268

This section provides more technical insights into the vulnerability.

Vulnerability Description

The Sustainsys.Saml2 library incorrectly treats all incoming tokens as bearer tokens, potentially allowing attackers to exploit tokens with a different subject confirmation method.

Affected Systems and Versions

Affected Product: Saml2
Vendor: Sustainsys
Vulnerable Versions:
< 1.0.2

= 2.0.0, <= 2.6.0

Exploitation Mechanism

Attackers could gain access to Saml2 tokens with a different subject confirmation method than bearer and use them to create a login session.

Mitigation and Prevention

Protecting systems from this vulnerability is crucial.

Immediate Steps to Take

Update to patched versions 1.0.2 or 2.7.0.
Monitor for any unauthorized login sessions.

Long-Term Security Practices

Implement multi-factor authentication.
Regularly review and update authentication mechanisms.

Patching and Updates

Apply security patches promptly.