CVE-2023-50015
📋 TL;DR
This vulnerability allows remote attackers to escalate privileges on affected Grandstream GXP14XX and GXP16XX VoIP phones by exploiting incorrect access control with end-user session tokens. Attackers can gain administrative access without proper authentication. Organizations using these specific phone models with vulnerable firmware are affected.
💻 Affected Systems
- Grandstream GXP14XX series
- Grandstream GXP16XX series
⚠️ 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
Complete compromise of VoIP phone with administrative access, enabling call interception, call spoofing, network pivoting, and persistent backdoor installation.
Likely Case
Unauthorized administrative access to phone configuration, enabling call monitoring, call redirection, and potential lateral movement to other network devices.
If Mitigated
Limited impact with proper network segmentation and monitoring, though phone functionality could still be disrupted.
🎯 Exploit Status
Exploitation requires obtaining or guessing a valid end-user session token, but the access control bypass is straightforward once token is acquired.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: GXP14XX: 1.0.8.10 or later; GXP16XX: 1.0.7.14 or later
Vendor Advisory: https://www.grandstream.com/support/security-advisories
Restart Required: Yes
Instructions:
1. Download latest firmware from Grandstream support portal. 2. Log into phone web interface as admin. 3. Navigate to Maintenance > Upgrade. 4. Upload firmware file. 5. Click Upgrade and wait for reboot.
🔧 Temporary Workarounds
Network Segmentation
allIsolate VoIP phones in separate VLAN with restricted access to management interfaces.
Access Control Lists
allImplement firewall rules to restrict access to phone web interfaces to authorized management stations only.
🧯 If You Can't Patch
- Segment VoIP network completely from other critical systems
- Disable remote web interface access and require VPN for management
🔍 How to Verify
Check if Vulnerable:
Log into phone web interface, navigate to Status > System Status, check firmware version matches affected range.Check Version:
curl -k https://[phone-ip]/cgi-bin/api-sys_operation?passcode=admin | grep firmwareVerify Fix Applied:
After update, verify firmware version shows 1.0.8.10+ for GXP14XX or 1.0.7.14+ for GXP16XX in System Status.📡 Detection & Monitoring
Log Indicators:
- Multiple failed login attempts followed by successful admin login from non-admin user
- Configuration changes from unexpected IP addresses
Network Indicators:
- HTTP POST requests to /cgi-bin/api-sys_operation with privilege escalation parameters
- Unusual administrative traffic patterns to phone management interfaces
SIEM Query:
source="voip-phones" AND (event="admin_login" AND user!="admin") OR (url_path="/cgi-bin/api-sys_operation" AND method="POST")