CVE-2021-3717
📋 TL;DR
CVE-2021-3717 is a security flaw in Wildfly's elytron configuration that incorrectly handles JBOSS_LOCAL_USER challenges. This allows any local user on the machine to gain JBOSS_LOCAL_USER access, potentially compromising confidentiality, integrity, and availability. It affects wildfly-core versions prior to 17.0.
💻 Affected Systems
- Wildfly
- wildfly-core
📦 What is this software?
Jboss Enterprise Application Platform by Redhat
View all CVEs affecting Jboss Enterprise Application Platform →
Jboss Enterprise Application Platform by Redhat
View all CVEs affecting Jboss Enterprise Application Platform →
⚠️ Risk & Real-World Impact
Worst Case
Any local user gains administrative access to Wildfly, leading to complete system compromise, data theft, service disruption, and lateral movement within the environment.
Likely Case
Local users with legitimate access escalate privileges to gain unauthorized control over Wildfly applications and services.
If Mitigated
With proper access controls and network segmentation, impact is limited to the local machine where Wildfly runs.
🎯 Exploit Status
Exploitation requires local user access but is straightforward once local access is obtained.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: wildfly-core 17.0 and later
Vendor Advisory: https://bugzilla.redhat.com/show_bug.cgi?id=1991305
Restart Required: Yes
Instructions:
1. Upgrade wildfly-core to version 17.0 or later. 2. Restart all Wildfly services. 3. Verify the fix by checking the version and testing authentication.
🔧 Temporary Workarounds
Disable JBOSS_LOCAL_USER authentication
allRemove or disable JBOSS_LOCAL_USER authentication mechanism in elytron configuration
Edit elytron configuration files to remove JBOSS_LOCAL_USER references
Restrict local user access
allImplement strict access controls to limit which users can access the Wildfly server
Use OS-level access controls to restrict user permissions
🧯 If You Can't Patch
- Implement strict local user access controls and monitoring
- Isolate affected systems using network segmentation
🔍 How to Verify
Check if Vulnerable:
Check wildfly-core version and verify if using elytron with JBOSS_LOCAL_USER authenticationCheck Version:
$WILDFLY_HOME/bin/jboss-cli.sh --versionVerify Fix Applied:
Confirm wildfly-core version is 17.0+ and test that local users cannot gain unauthorized JBOSS_LOCAL_USER access📡 Detection & Monitoring
Log Indicators:
- Unauthorized authentication attempts using JBOSS_LOCAL_USER
- Privilege escalation events in Wildfly logs
Network Indicators:
- Unusual local authentication patterns to Wildfly services
SIEM Query:
source="wildfly" AND (event="authentication" OR event="authorization") AND result="failure" AND user="*"