CVE-2022-41912 Overview
CVE-2022-41912 is a critical authentication bypass vulnerability in the crewjam/saml Go library prior to version 0.4.9. The vulnerability allows attackers to bypass SAML authentication when processing SAML responses containing multiple Assertion elements. This flaw enables unauthorized access to protected resources by manipulating the structure of SAML responses.
Critical Impact
Attackers can bypass authentication entirely, gaining unauthorized access to SAML-protected applications without valid credentials. This could lead to complete compromise of user accounts and sensitive data.
Affected Products
- saml_project saml (Go library versions prior to 0.4.9)
Discovery Timeline
- 2022-11-28 - CVE CVE-2022-41912 published to NVD
- 2024-11-21 - Last updated in NVD database
Technical Details for CVE-2022-41912
Vulnerability Analysis
This authentication bypass vulnerability (CWE-287) exists in how the crewjam/saml Go library processes SAML responses. The library fails to properly validate SAML responses that contain multiple Assertion elements. When a SAML response includes more than one Assertion, the library may incorrectly process an unsigned or maliciously crafted Assertion while the signature verification is performed on a different, legitimate Assertion.
This signature bypass technique allows attackers to inject arbitrary identity claims that the service provider will accept as authenticated. The vulnerability is particularly dangerous because SAML is widely used for enterprise single sign-on (SSO) implementations, meaning successful exploitation could grant attackers access to multiple connected applications.
Root Cause
The root cause lies in improper validation logic when handling SAML responses with multiple Assertion elements. The library does not ensure that signature validation is applied to the same Assertion element that is subsequently used for authentication decisions. This allows an attacker to craft a response where a valid signature covers one Assertion while a separate, malicious unsigned Assertion is used for identity extraction.
Attack Vector
The attack is network-based and requires no privileges or user interaction. An attacker can exploit this vulnerability by intercepting or crafting SAML responses and injecting additional unsigned Assertion elements. The malicious response is then sent to the service provider, which processes the unsigned Assertion and grants access based on the attacker-controlled identity claims.
The attack flow involves crafting a SAML response with multiple Assertion elements, where the signed Assertion may contain legitimate but irrelevant data, while the unsigned Assertion contains the attacker's desired identity claims. When the library validates the signature on the first Assertion but extracts identity information from the second unsigned Assertion, authentication is bypassed.
Detection Methods for CVE-2022-41912
Indicators of Compromise
- SAML responses containing multiple Assertion elements in authentication logs
- Unexpected user sessions or access from identities not matching IdP records
- Authentication events without corresponding IdP-initiated sign-on records
Detection Strategies
- Monitor SAML authentication logs for responses with unusual structures or multiple Assertions
- Implement SAML response schema validation to detect malformed responses
- Deploy web application firewall rules to inspect SAML traffic for suspicious patterns
- Enable detailed logging of SAML assertion processing to identify signature bypass attempts
Monitoring Recommendations
- Review authentication logs for anomalous SAML response patterns
- Audit user sessions for signs of unauthorized access following SAML authentication
- Monitor for unexpected privilege changes or access to sensitive resources post-authentication
How to Mitigate CVE-2022-41912
Immediate Actions Required
- Upgrade crewjam/saml Go library to version 0.4.9 or later immediately
- Review authentication logs for signs of exploitation
- Audit user accounts and sessions authenticated via SAML for unauthorized access
- Consider temporarily disabling SAML authentication if patching is delayed
Patch Information
The vulnerability has been corrected in version 0.4.9 of the crewjam/saml library. The fix is available in GitHub commit aee3fb1edeeaf1088fcb458727e0fd863d277f8b. Organizations should update their Go dependencies to include this patched version. Additional details are available in the GitHub Security Advisory.
Workarounds
- No workarounds are available other than upgrading to the fixed version 0.4.9
- Consider implementing additional authentication factors while awaiting patch deployment
- Apply network-level restrictions to limit SAML endpoint exposure if possible
# Update Go dependencies to patched version
go get github.com/crewjam/saml@v0.4.9
go mod tidy
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
