CVE-2023-1523
📋 TL;DR
This vulnerability allows malicious snaps to inject terminal input via TIOCLINUX ioctl, potentially executing arbitrary commands outside the snap sandbox after the snap exits. Only affects snaps running on virtual consoles (not graphical terminal emulators). Systems using snap packages on Linux virtual consoles are vulnerable.
💻 Affected Systems
- snapd
📦 What is this software?
Snapd by Canonical
Ubuntu Linux by Canonical
Ubuntu Linux by Canonical
Ubuntu Linux by Canonical
Ubuntu Linux by Canonical
Ubuntu Linux by Canonical
Ubuntu Linux by Canonical
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with root privileges through arbitrary command execution outside snap confinement.
Likely Case
Privilege escalation allowing malicious snaps to break out of sandbox and access host system resources.
If Mitigated
No impact if using graphical terminals or patched snapd versions.
🎯 Exploit Status
Requires malicious snap package and virtual console access.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: snapd 2.58.2
Vendor Advisory: https://ubuntu.com/security/notices/USN-6125-1
Restart Required: No
Instructions:
1. Update snapd: sudo snap refresh snapd 2. Verify version: snap version 3. Restart affected snaps if necessary.
🔧 Temporary Workarounds
Use graphical terminals
linuxRun snaps only in graphical terminal emulators (xterm, gnome-terminal, etc.) which are not vulnerable.
Disable TIOCLINUX ioctl
linuxRestrict TIOCLINUX ioctl usage through kernel parameters or security modules.
🧯 If You Can't Patch
- Avoid running snaps on virtual consoles
- Implement strict snap review policies to prevent malicious snaps
🔍 How to Verify
Check if Vulnerable:
Check snapd version: snap version | grep snapdCheck Version:
snap version | grep snapdVerify Fix Applied:
Verify snapd version is 2.58.2 or higher: snap version📡 Detection & Monitoring
Log Indicators:
- Unusual TIOCLINUX ioctl calls from snap processes
- Snap processes accessing terminal devices unexpectedly
Network Indicators:
- Local-only exploit, no network indicators
SIEM Query:
process.name:snap* AND syscall.name:ioctl AND syscall.args.cmd:TIOCLINUX🔗 References
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-1523
- https://github.com/snapcore/snapd/pull/12849
- https://marc.info/?l=oss-security&m=167879021709955&w=2
- https://ubuntu.com/security/notices/USN-6125-1
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-1523
- https://github.com/snapcore/snapd/pull/12849
- https://marc.info/?l=oss-security&m=167879021709955&w=2
- https://ubuntu.com/security/notices/USN-6125-1
