CVE-2019-3465
📋 TL;DR
CVE-2019-3465 is a signature validation bypass vulnerability in XmlSecLibs that allows authenticated attackers to forge XML signatures. This enables impersonation of other users or privilege escalation by crafting malicious XML messages. Systems using XmlSecLibs (like SimpleSAMLphp) for XML signature validation are affected.
💻 Affected Systems
- XmlSecLibs
- SimpleSAMLphp
- Other applications using XmlSecLibs for XML signature validation
📦 What is this software?
Simplesamlphp by Simplesamlphp
Xmlseclibs by Xmlseclibs Project
Xmlseclibs by Xmlseclibs Project
Xmlseclibs by Xmlseclibs Project
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise through privilege escalation to administrative access, allowing data theft, service disruption, and lateral movement.
Likely Case
Authenticated attackers impersonating other users to access unauthorized resources or perform actions with elevated privileges.
If Mitigated
Limited impact with proper network segmentation, strong authentication controls, and monitoring of XML processing.
🎯 Exploit Status
Exploitation requires authenticated access but the signature bypass technique is straightforward once authenticated.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 3.0.3
Vendor Advisory: https://github.com/robrichards/xmlseclibs/commit/0a53d3c3aa87564910cae4ed01416441d3ae0db5
Restart Required: Yes
Instructions:
1. Update XmlSecLibs to version 3.0.3 or later. 2. If using SimpleSAMLphp, update to a version that includes the patched XmlSecLibs. 3. Restart affected services. 4. Test XML signature functionality.
🔧 Temporary Workarounds
Disable XML signature validation
allTemporarily disable XML signature validation if not critical for functionality
Network isolation
allRestrict access to XML processing endpoints to trusted networks only
🧯 If You Can't Patch
- Implement strict input validation and sanitization for all XML messages
- Deploy web application firewall rules to detect and block malformed XML signatures
🔍 How to Verify
Check if Vulnerable:
Check XmlSecLibs version in your application dependencies or vendor packagesCheck Version:
php -r "require_once 'vendor/autoload.php'; echo \RobRichards\XMLSecLibs\XMLSecurityDSig::VERSION;"Verify Fix Applied:
Confirm XmlSecLibs version is 3.0.3 or higher and test XML signature validation with known good and bad signatures📡 Detection & Monitoring
Log Indicators:
- Failed XML signature validations
- Unusual authentication patterns
- XML parsing errors
Network Indicators:
- Unusual XML payloads to authentication endpoints
- Multiple failed signature validations from single source
SIEM Query:
source="application_logs" AND (message="*XML signature*" OR message="*authentication failure*")🔗 References
- https://github.com/robrichards/xmlseclibs/commit/0a53d3c3aa87564910cae4ed01416441d3ae0db5
- https://lists.debian.org/debian-lts-announce/2019/11/msg00003.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/7KID7C4AZPYYIZQIPSLANP4R2RQR6YK3/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/AB34ILMJ67CUROBOR6YPKB46VHXLOAJ4/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BBKVDUZ7G5ZOUO4BFJWLNJ6VOKBQJX5U/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BNFMY5RRLU63P25HEBVDO5KAVI7TX7JV/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ESKJTWLE7QZBQ3EKMYXKMBQG3JDEJWM6/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HBE2SJSXG7J4XYLJ2H6HC2VPPOG2OMUN/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MAWOVYLZKYDCQBLQEJCFAAD3KQTBPHXE/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/OCSR3V6LNWJAD37VQB6M2K7P4RQSCVFG/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XBSSRV5Q7JFCYO46A3EN624UZ4KXFQ2M/
- https://seclists.org/bugtraq/2019/Nov/8
- https://simplesamlphp.org/security/201911-01
- https://www.debian.org/security/2019/dsa-4560
- https://www.tenable.com/security/tns-2019-09
- https://github.com/robrichards/xmlseclibs/commit/0a53d3c3aa87564910cae4ed01416441d3ae0db5
- https://lists.debian.org/debian-lts-announce/2019/11/msg00003.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/7KID7C4AZPYYIZQIPSLANP4R2RQR6YK3/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/AB34ILMJ67CUROBOR6YPKB46VHXLOAJ4/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BBKVDUZ7G5ZOUO4BFJWLNJ6VOKBQJX5U/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BNFMY5RRLU63P25HEBVDO5KAVI7TX7JV/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ESKJTWLE7QZBQ3EKMYXKMBQG3JDEJWM6/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HBE2SJSXG7J4XYLJ2H6HC2VPPOG2OMUN/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MAWOVYLZKYDCQBLQEJCFAAD3KQTBPHXE/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/OCSR3V6LNWJAD37VQB6M2K7P4RQSCVFG/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XBSSRV5Q7JFCYO46A3EN624UZ4KXFQ2M/
- https://seclists.org/bugtraq/2019/Nov/8
- https://simplesamlphp.org/security/201911-01
- https://www.debian.org/security/2019/dsa-4560
- https://www.tenable.com/security/tns-2019-09
