CVE-2022-31213
📋 TL;DR
CVE-2022-31213 is a NULL pointer dereference vulnerability in dbus-broker that can cause crashes or potentially allow arbitrary code execution when processing a malicious XML configuration file. This affects systems running dbus-broker versions before 31. The vulnerability requires local access to supply a malformed config file.
💻 Affected Systems
- dbus-broker
📦 What is this software?
Dbus Broker by Dbus Broker Project
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to full system compromise if combined with other vulnerabilities, though this requires specific memory layout conditions.
Likely Case
Denial of service through application crash or system instability when processing malicious configuration files.
If Mitigated
Limited to denial of service with proper privilege separation and minimal impact if system restarts automatically.
🎯 Exploit Status
Exploitation requires local access to supply malicious configuration and depends on specific memory conditions for code execution.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Version 31 and later
Vendor Advisory: https://github.com/bus1/dbus-broker/compare/v30...v31
Restart Required: Yes
Instructions:
1. Update dbus-broker to version 31 or later using your distribution's package manager. 2. For source installations: download v31+ from GitHub, compile, and replace existing installation. 3. Restart dbus-broker service: 'systemctl restart dbus-broker' or equivalent.
🔧 Temporary Workarounds
Restrict configuration file permissions
linuxLimit write access to dbus-broker configuration directories to prevent malicious configuration injection.
chmod 644 /etc/dbus-broker/*.conf
chown root:root /etc/dbus-broker/*.conf
🧯 If You Can't Patch
- Monitor for unauthorized configuration file changes using file integrity monitoring tools.
- Implement strict access controls to prevent unauthorized users from modifying dbus-broker configuration files.
🔍 How to Verify
Check if Vulnerable:
Check dbus-broker version: 'dbus-broker --version' or 'rpm -q dbus-broker' or 'dpkg -l | grep dbus-broker'. If version is below 31, system is vulnerable.Check Version:
dbus-broker --version 2>/dev/null || rpm -q dbus-broker 2>/dev/null || dpkg -l | grep dbus-brokerVerify Fix Applied:
After update, verify version is 31 or higher using same commands and ensure dbus-broker service is running without crashes.📡 Detection & Monitoring
Log Indicators:
- dbus-broker crash logs in journalctl
- Segmentation fault errors related to dbus-broker
- Unexpected service restarts of dbus-broker
Network Indicators:
- Loss of D-Bus communication to services
- Service discovery failures
SIEM Query:
source="journald" AND process="dbus-broker" AND ("segmentation fault" OR "SIGSEGV" OR "crash")🔗 References
- https://github.com/bus1/dbus-broker/compare/v30...v31
- https://sec-consult.com/vulnerability-lab/advisory/memory-corruption-vulnerabilities-dbus-broker/
- https://security.gentoo.org/glsa/202305-04
- https://github.com/bus1/dbus-broker/compare/v30...v31
- https://sec-consult.com/vulnerability-lab/advisory/memory-corruption-vulnerabilities-dbus-broker/
- https://security.gentoo.org/glsa/202305-04
