CVE-2020-12865
📋 TL;DR
CVE-2020-12865 is a heap buffer overflow vulnerability in SANE Backends that allows arbitrary code execution. Attackers on the same local network as vulnerable systems can exploit this to gain control. This affects systems running SANE Backends before version 1.0.30 for scanner/device management.
💻 Affected Systems
- SANE Backends
📦 What is this software?
Leap by Opensuse
Leap by Opensuse
Sane Backends by Sane Project
Ubuntu Linux by Canonical
Ubuntu Linux by Canonical
Ubuntu Linux by Canonical
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution with full system compromise, allowing attackers to install malware, steal data, or pivot to other systems.
Likely Case
Local network attackers gaining shell access on vulnerable systems, potentially leading to lateral movement within the network.
If Mitigated
Limited impact with proper network segmentation and access controls preventing unauthorized devices from connecting to SANE services.
🎯 Exploit Status
Exploitation requires network access to SANE services but no authentication. The heap overflow can be triggered by malicious devices.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.0.30 and later
Vendor Advisory: https://alioth-lists.debian.net/pipermail/sane-announce/2020/000041.html
Restart Required: Yes
Instructions:
1. Update SANE Backends to version 1.0.30 or later using your distribution's package manager. 2. For Debian/Ubuntu: sudo apt update && sudo apt install sane-backends. 3. For RHEL/CentOS: sudo yum update sane-backends. 4. Restart any services using SANE.
🔧 Temporary Workarounds
Network Access Restriction
linuxRestrict network access to SANE services to trusted devices only using firewall rules.
sudo iptables -A INPUT -p tcp --dport 6566 -s TRUSTED_IP -j ACCEPT
sudo iptables -A INPUT -p tcp --dport 6566 -j DROP
Disable Network Scanning
linuxConfigure SANE to only allow local scanner access, disabling network functionality.
Edit /etc/sane.d/saned.conf and set 'localhost' or remove network configurations
sudo systemctl restart saned
🧯 If You Can't Patch
- Isolate vulnerable systems on separate network segments with strict access controls.
- Disable SANE network services entirely and use local-only scanner connections.
🔍 How to Verify
Check if Vulnerable:
Check SANE Backends version: scanimage --version | grep 'SANE Backends'Check Version:
scanimage --version | grep 'SANE Backends'Verify Fix Applied:
Verify version is 1.0.30 or later: scanimage --version | grep -E 'SANE Backends.*1\.0\.3[0-9]|1\.[1-9]'📡 Detection & Monitoring
Log Indicators:
- Unusual network connections to SANE port 6566 from unexpected IPs
- SANE service crashes or abnormal termination in system logs
Network Indicators:
- Malformed network packets to SANE services
- Unexpected device enumeration requests from network scanners
SIEM Query:
source="*saned*" AND (event="crash" OR event="segmentation fault") OR destination_port=6566 AND source_ip NOT IN [trusted_ips]🔗 References
- http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00079.html
- http://lists.opensuse.org/opensuse-security-announce/2020-11/msg00003.html
- https://alioth-lists.debian.net/pipermail/sane-announce/2020/000041.html
- https://lists.debian.org/debian-lts-announce/2020/08/msg00029.html
- https://lists.debian.org/debian-lts-announce/2020/10/msg00010.html
- https://securitylab.github.com/advisories/GHSL-2020-075-libsane
- https://usn.ubuntu.com/4470-1/
- http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00079.html
- http://lists.opensuse.org/opensuse-security-announce/2020-11/msg00003.html
- https://alioth-lists.debian.net/pipermail/sane-announce/2020/000041.html
- https://lists.debian.org/debian-lts-announce/2020/08/msg00029.html
- https://lists.debian.org/debian-lts-announce/2020/10/msg00010.html
- https://securitylab.github.com/advisories/GHSL-2020-075-libsane
- https://usn.ubuntu.com/4470-1/
