CVE-2022-28494
📋 TL;DR
This CVE describes a command injection vulnerability in TOTOLink CP900 outdoor CPE devices that allows attackers to execute arbitrary commands via the filename parameter in the setUpgradeFW function. Attackers can achieve remote code execution with high privileges. This affects all users of the vulnerable TOTOLink CP900 firmware version.
💻 Affected Systems
- TOTOLink outdoor CPE CP900
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise allowing attackers to install persistent backdoors, pivot to internal networks, intercept traffic, or use the device as part of a botnet.
Likely Case
Remote code execution leading to device takeover, credential theft, and network reconnaissance.
If Mitigated
Limited impact if device is behind firewall with strict inbound rules and network segmentation.
🎯 Exploit Status
Public proof-of-concept code exists in GitHub repositories. The exploit requires sending a crafted HTTP request to the vulnerable endpoint.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: No official vendor advisory found
Restart Required: No
Instructions:
Check TOTOLink official website for firmware updates. If available, download the latest firmware and upload via the web interface's firmware upgrade section.
🔧 Temporary Workarounds
Network Access Control
allRestrict access to the device's management interface using firewall rules
Disable Remote Management
allDisable WAN-side access to the management interface if enabled
🧯 If You Can't Patch
- Isolate the device in a separate VLAN with strict firewall rules preventing inbound connections
- Implement network monitoring for suspicious traffic to/from the device
🔍 How to Verify
Check if Vulnerable:
Check firmware version in web interface: System Tools > Firmware Upgrade. If version is V6.3c.566_B20171026, device is vulnerable.Check Version:
No CLI command available. Must check via web interface at System Tools > Firmware UpgradeVerify Fix Applied:
Verify firmware version has been updated to a version newer than V6.3c.566_B20171026📡 Detection & Monitoring
Log Indicators:
- Unusual firmware upgrade attempts
- HTTP requests to /cgi-bin/cstecgi.cgi with filename parameter containing shell metacharacters
Network Indicators:
- HTTP POST requests to /cgi-bin/cstecgi.cgi with suspicious filename parameters
- Outbound connections from device to unexpected destinations
SIEM Query:
http.method:POST AND http.uri:"/cgi-bin/cstecgi.cgi" AND http.post_data:*filename=* AND (http.post_data:*;* OR http.post_data:*|* OR http.post_data:*`* OR http.post_data:*$(*)