CVE-2023-2091
📋 TL;DR
This critical vulnerability in KylinSoft youker-assistant on KylinOS allows local attackers to execute arbitrary operating system commands through command injection in the adjust_cpufreq_scaling_governer function. Attackers can gain elevated privileges and potentially take full control of affected systems. Only KylinOS users with youker-assistant installed are affected.
💻 Affected Systems
- KylinSoft youker-assistant
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with root privileges, allowing installation of persistent backdoors, data exfiltration, and lateral movement within the network.
Likely Case
Local privilege escalation leading to unauthorized administrative access, configuration changes, and potential data theft from the compromised system.
If Mitigated
Limited impact with proper access controls and monitoring, potentially detected before significant damage occurs.
🎯 Exploit Status
Exploit details have been publicly disclosed and the vulnerability is straightforward to exploit locally. Requires some level of local access to the system.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 3.1.4.13
Vendor Advisory: https://kylinos.cn/support/loophole/patch/3375.html
Restart Required: Yes
Instructions:
1. Backup current configuration. 2. Update youker-assistant to version 3.1.4.13 using KylinOS package manager. 3. Restart the system to ensure changes take effect. 4. Verify the update was successful.
🔧 Temporary Workarounds
Remove or disable youker-assistant
linuxTemporarily remove or disable the vulnerable component until patching is possible
sudo apt-get remove youker-assistant
sudo systemctl disable youker-assistant
Restrict execution permissions
linuxRemove execute permissions from vulnerable binaries to prevent exploitation
sudo chmod -x /usr/bin/youker-assistant
sudo chmod -x /usr/lib/youker-assistant/*
🧯 If You Can't Patch
- Implement strict access controls to limit local user privileges
- Monitor system logs for suspicious command execution patterns
🔍 How to Verify
Check if Vulnerable:
Check youker-assistant version: dpkg -l | grep youker-assistantCheck Version:
dpkg -l | grep youker-assistantVerify Fix Applied:
Verify version is 3.1.4.13 or higher: dpkg -l | grep youker-assistant | grep '3.1.4.13'📡 Detection & Monitoring
Log Indicators:
- Unusual command execution from youker-assistant processes
- Suspicious system calls from adjust_cpufreq_scaling_governer function
- Unexpected privilege escalation attempts
Network Indicators:
- Outbound connections from youker-assistant process to unexpected destinations
SIEM Query:
process_name:"youker-assistant" AND (cmdline:"adjust_cpufreq_scaling_governer" OR cmdline:"/bin/sh" OR cmdline:"/bin/bash")🔗 References
- https://github.com/i900008/vulndb/blob/main/youker-assistant_vuln.md
- https://kylinos.cn/support/loophole/patch/3375.html
- https://vuldb.com/?ctiid.226099
- https://vuldb.com/?id.226099
- https://github.com/i900008/vulndb/blob/main/youker-assistant_vuln.md
- https://kylinos.cn/support/loophole/patch/3375.html
- https://vuldb.com/?ctiid.226099
- https://vuldb.com/?id.226099
