CVE-2025-32743
📋 TL;DR
This vulnerability in ConnMan's DNS proxy allows attackers to crash the service or potentially execute arbitrary code by sending DNS responses with the TC (Truncated) bit set. It affects all systems running ConnMan up to version 1.44, particularly Linux-based IoT devices and embedded systems that use ConnMan for network management.
💻 Affected Systems
- ConnMan
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, privilege escalation, or persistent backdoor installation.
Likely Case
Denial of service causing ConnMan to crash, disrupting network connectivity on affected devices.
If Mitigated
Limited impact if ConnMan runs in a sandboxed environment with minimal privileges and network exposure.
🎯 Exploit Status
Exploitation requires sending specially crafted DNS responses to the target's DNS proxy. No authentication needed as DNS responses are processed automatically.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.45 or later
Vendor Advisory: https://git.kernel.org/pub/scm/network/connman/connman.git/
Restart Required: Yes
Instructions:
1. Update ConnMan to version 1.45 or later. 2. For package managers: 'sudo apt update && sudo apt upgrade connman' (Debian/Ubuntu) or 'sudo yum update connman' (RHEL/CentOS). 3. Restart ConnMan service: 'sudo systemctl restart connman'.
🔧 Temporary Workarounds
Disable DNS proxy
linuxTemporarily disable ConnMan's DNS proxy functionality to prevent processing of malicious DNS responses.
sudo systemctl stop connman
Edit /etc/connman/main.conf to disable DNS proxy
sudo systemctl start connman
Network filtering
linuxBlock external DNS responses with TC bit set at network perimeter.
iptables -A INPUT -p udp --dport 53 -m string --hex-string '|81 80|' --algo kmp -j DROP
🧯 If You Can't Patch
- Isolate affected systems from untrusted networks, especially DNS traffic.
- Run ConnMan with minimal privileges and in a containerized/sandboxed environment.
🔍 How to Verify
Check if Vulnerable:
Check ConnMan version: 'connmand --version' or 'dpkg -l | grep connman' or 'rpm -qa | grep connman'. If version is 1.44 or earlier, system is vulnerable.Check Version:
connmand --version 2>/dev/null || dpkg -l | grep connman || rpm -qa | grep connmanVerify Fix Applied:
Verify version is 1.45 or later using same commands. Test DNS functionality remains operational.📡 Detection & Monitoring
Log Indicators:
- ConnMan crash logs in systemd journal: 'journalctl -u connman --since today'
- Segmentation fault or memory corruption errors in /var/log/syslog
Network Indicators:
- Unusual DNS responses with TC bit set from unexpected sources
- Spike in DNS traffic to ConnMan's listening port (typically 53)
SIEM Query:
source="connman" AND ("segmentation fault" OR "crash" OR "SIGSEGV")