CVE-2022-42011 Overview
CVE-2022-42011 is a Denial of Service (DoS) vulnerability affecting D-Bus, the widely-used inter-process communication (IPC) mechanism found in Linux systems and other platforms. The vulnerability exists in versions prior to 1.12.24, 1.13.x and 1.14.x before 1.14.4, and 1.15.x before 1.15.2. An authenticated attacker can exploit this flaw by sending specially crafted messages where the array length is inconsistent with the size of the element type, causing dbus-daemon and other applications using libdbus to crash.
Critical Impact
Authenticated attackers can crash the D-Bus daemon and dependent applications through malformed array length messages, potentially disrupting core system services and inter-process communication on affected Linux systems.
Affected Products
- Freedesktop D-Bus versions prior to 1.12.24
- Freedesktop D-Bus versions 1.13.x and 1.14.x prior to 1.14.4
- Freedesktop D-Bus versions 1.15.x prior to 1.15.2
- Fedora 35, 36, and 37
Discovery Timeline
- 2022-10-10 - CVE-2022-42011 published to NVD
- 2025-06-09 - Last updated in NVD database
Technical Details for CVE-2022-42011
Vulnerability Analysis
This vulnerability stems from improper validation of array bounds (CWE-129) within the D-Bus message parsing logic. When D-Bus receives a message containing an array, it should verify that the declared array length is consistent with the actual size of the array elements. However, vulnerable versions fail to properly validate this consistency, allowing malformed messages to trigger undefined behavior.
The D-Bus daemon serves as a critical system component on Linux systems, facilitating communication between desktop applications, system services, and various components. A successful exploitation disrupts this communication backbone, potentially affecting system stability and the availability of dependent services.
Root Cause
The root cause is an improper validation of array indices (CWE-129) in the libdbus library. When processing incoming D-Bus messages, the library does not adequately verify that the declared array length matches the expected size based on the element type. This mismatch between the stated array length and the actual element size leads to memory access violations when the library attempts to process the array contents.
Attack Vector
The vulnerability is exploitable over the network by authenticated attackers. The attack requires:
- Valid authentication to the D-Bus session or system bus
- The ability to send crafted D-Bus messages containing arrays with inconsistent length declarations
- The target system must be running a vulnerable version of dbus-daemon or applications linked against vulnerable libdbus
When a malformed message is received, the inconsistency between the array length field and the element type size causes the D-Bus daemon or client applications to access memory incorrectly, resulting in a crash. Since D-Bus is integral to system operation on many Linux distributions, crashing the daemon can have cascading effects on dependent services and applications.
Detection Methods for CVE-2022-42011
Indicators of Compromise
- Unexpected crashes of dbus-daemon process with segmentation faults or memory access errors
- Core dumps from D-Bus related processes showing array parsing failures
- System logs indicating D-Bus service restarts or failures in /var/log/messages or journal
- Dependent services failing due to D-Bus communication interruptions
Detection Strategies
- Monitor for repeated dbus-daemon process crashes using process monitoring tools
- Implement log analysis for D-Bus error messages indicating malformed message reception
- Deploy intrusion detection rules to identify anomalous D-Bus message patterns
- Track service availability metrics for D-Bus dependent applications
Monitoring Recommendations
- Enable verbose logging for D-Bus daemon to capture message parsing errors
- Configure systemd to alert on dbus-daemon service failures and restarts
- Monitor system stability metrics for unexplained service disruptions
- Implement endpoint detection for unusual D-Bus session activity patterns
How to Mitigate CVE-2022-42011
Immediate Actions Required
- Update D-Bus to version 1.12.24, 1.14.4, or 1.15.2 or later depending on your version branch
- Apply vendor-specific patches from your Linux distribution
- Review and restrict D-Bus policy configurations to limit authenticated access where possible
- Monitor D-Bus daemon for unusual behavior until patches are applied
Patch Information
Updated versions are available that address this array length validation issue:
- D-Bus 1.12.24 and later for the 1.12.x stable branch
- D-Bus 1.14.4 and later for the 1.14.x branch
- D-Bus 1.15.2 and later for the 1.15.x development branch
For Fedora users, patches are available through the standard package repositories. Refer to the Fedora Package Announcements for specific update instructions. Gentoo users should consult GLSA 202305-08 for guidance. Additional technical details are available in GitLab Issue #413.
Workarounds
- Restrict access to D-Bus session and system buses to trusted users only through D-Bus policy files
- Implement network segmentation to limit exposure of D-Bus services
- Configure D-Bus policies in /etc/dbus-1/ to minimize the attack surface by limiting which services can be accessed
- Consider running critical services with alternative IPC mechanisms where feasible until patching is complete
# Configuration example: Update D-Bus on Fedora systems
sudo dnf update dbus dbus-libs
# Verify installed D-Bus version
dbus-daemon --version
# Restart D-Bus service after update (may require system restart)
sudo systemctl restart dbus
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
