CVE-2020-6923
📋 TL;DR
CVE-2020-6923 is a buffer overflow vulnerability in HP Linux Imaging and Printing (HPLIP) software that could allow attackers to execute arbitrary code or cause denial of service. This affects Linux systems running vulnerable versions of HPLIP. Users who have HPLIP installed for HP printer/scanner functionality are potentially affected.
💻 Affected Systems
- HP Linux Imaging and Printing (HPLIP)
⚠️ 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 with the privileges of the HPLIP process, potentially leading to full system compromise if the process runs with elevated privileges.
Likely Case
Denial of service through application crash, or limited code execution in the context of the HPLIP service.
If Mitigated
Minimal impact if the service runs with limited privileges and network access is restricted.
🎯 Exploit Status
Buffer overflow vulnerabilities typically require some technical expertise to exploit, but public exploit code could lower the barrier.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: HPLIP 3.20.6 and later
Vendor Advisory: https://support.hp.com/us-en/document/c06927115
Restart Required: Yes
Instructions:
1. Check current HPLIP version with 'hp-check -t'. 2. Update via package manager: 'sudo apt update && sudo apt upgrade hplip' (Debian/Ubuntu) or 'sudo yum update hplip' (RHEL/CentOS). 3. Restart affected services or reboot system.
🔧 Temporary Workarounds
Disable HPLIP services
linuxStop and disable HPLIP-related services if printer functionality is not required
sudo systemctl stop hplip
sudo systemctl disable hplip
Network isolation
linuxRestrict network access to HPLIP services using firewall rules
sudo ufw deny from any to any port 9100
sudo ufw deny from any to any port 631
🧯 If You Can't Patch
- Run HPLIP services with minimal privileges using SELinux/AppArmor
- Implement network segmentation to isolate systems with vulnerable HPLIP installations
🔍 How to Verify
Check if Vulnerable:
Run 'hp-check -t' and check if version is below 3.20.6Check Version:
hp-check -t | grep -i versionVerify Fix Applied:
Run 'hp-check -t' and confirm version is 3.20.6 or higher📡 Detection & Monitoring
Log Indicators:
- Segmentation fault or crash logs from hplip processes
- Unusual process creation from hplip service
Network Indicators:
- Unexpected connections to printer ports (9100, 631)
- Malformed network packets to HPLIP services
SIEM Query:
process_name:hplip AND (event_type:crash OR exit_code:139)