CVE-2023-38317
📋 TL;DR
CVE-2023-38317 is a command injection vulnerability in OpenNDS that allows attackers with access to the configuration file to execute arbitrary operating system commands. This affects OpenNDS installations before version 10.1.3, primarily used for captive portal authentication on networks.
💻 Affected Systems
- OpenNDS
📦 What is this software?
Opennds by Opennds
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with root-level command execution, allowing attackers to install malware, pivot to other systems, or disrupt network services.
Likely Case
Local privilege escalation leading to unauthorized network access, credential theft, or captive portal manipulation.
If Mitigated
Limited impact with proper file permissions preventing unauthorized configuration file access.
🎯 Exploit Status
Exploitation requires access to modify the configuration file, which may be protected by file permissions.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 10.1.3
Vendor Advisory: https://github.com/openNDS/openNDS/releases/tag/v10.1.3
Restart Required: Yes
Instructions:
1. Backup current configuration. 2. Update OpenNDS to version 10.1.3 or later. 3. Restart OpenNDS service. 4. Verify the update with version check.
🔧 Temporary Workarounds
Restrict configuration file permissions
linuxSet strict file permissions on OpenNDS configuration files to prevent unauthorized modification.
chmod 600 /etc/opennds/*.conf
chown root:root /etc/opennds/*.conf
Network segmentation
allIsolate OpenNDS instances from untrusted networks and limit administrative access.
🧯 If You Can't Patch
- Implement strict file permissions (chmod 600) on all OpenNDS configuration files
- Monitor configuration files for unauthorized changes using file integrity monitoring
🔍 How to Verify
Check if Vulnerable:
Check OpenNDS version and compare with vulnerable range (before 10.1.3).Check Version:
opennds --versionVerify Fix Applied:
Confirm version is 10.1.3 or later and test configuration file sanitization.📡 Detection & Monitoring
Log Indicators:
- Unexpected configuration file modifications
- Unusual command execution in system logs
- Failed authentication attempts to configuration files
Network Indicators:
- Unusual outbound connections from OpenNDS host
- Anomalous captive portal behavior
SIEM Query:
source="opennds" AND (event="config_modified" OR event="command_exec")🔗 References
- https://github.com/openNDS/openNDS/blob/master/ChangeLog
- https://github.com/openNDS/openNDS/releases/tag/v10.1.3
- https://openwrt.org/docs/guide-user/services/captive-portal/opennds
- https://www.forescout.com/resources/sierra21-vulnerabilities
- https://github.com/openNDS/openNDS/blob/master/ChangeLog
- https://github.com/openNDS/openNDS/releases/tag/v10.1.3
- https://openwrt.org/docs/guide-user/services/captive-portal/opennds
- https://www.forescout.com/resources/sierra21-vulnerabilities
