CVE-2019-19825
📋 TL;DR
This vulnerability allows attackers to bypass CAPTCHA protection on affected TOTOLINK routers by retrieving the CAPTCHA text via a specific POST request. Once valid credentials are obtained, attackers can perform router actions using HTTP requests with Basic Authentication. This affects multiple TOTOLINK router models running Realtek SDK firmware.
💻 Affected Systems
- TOTOLINK A3002RU
- TOTOLINK A702R
- TOTOLINK N301RT
- TOTOLINK N302R
- TOTOLINK N300RT
- TOTOLINK N200RE
- TOTOLINK N150RT
- TOTOLINK N100RE
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete router compromise allowing attackers to reconfigure network settings, intercept traffic, install malware, or use the router as part of a botnet.
Likely Case
Unauthorized access to router administration interface leading to network configuration changes, DNS hijacking, or credential theft.
If Mitigated
Limited impact if routers are behind firewalls with restricted WAN access and strong administrative credentials.
🎯 Exploit Status
Exploit requires sending POST request to boafrm/formLogin URI with specific parameters. Public exploit code is available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check vendor for specific fixed versions for each model
Vendor Advisory: https://www.totolink.net/
Restart Required: Yes
Instructions:
1. Check TOTOLINK website for firmware updates for your specific router model. 2. Download the latest firmware. 3. Log into router admin interface. 4. Navigate to firmware upgrade section. 5. Upload and install new firmware. 6. Reboot router.
🔧 Temporary Workarounds
Disable WAN administration access
allPrevent external access to router administration interface
Log into router admin interface
Navigate to Remote Management/Administration settings
Disable WAN/Internet access to admin interface
Change default credentials
allUse strong, unique administrative passwords
Log into router admin interface
Navigate to Administration/Password settings
Change admin password to strong, unique value
🧯 If You Can't Patch
- Isolate affected routers in separate network segments with strict firewall rules
- Implement network monitoring for suspicious POST requests to boafrm/formLogin URI
🔍 How to Verify
Check if Vulnerable:
Send POST request to http://[router-ip]/boafrm/formLogin with data {"topicurl":"setting/getSanvas"} and check if CAPTCHA text is returnedCheck Version:
Log into router admin interface and check firmware version in System Status or About sectionVerify Fix Applied:
Attempt the same POST request after patching - should not return CAPTCHA text or should return error📡 Detection & Monitoring
Log Indicators:
- POST requests to /boafrm/formLogin with topicurl parameter
- Multiple failed login attempts followed by successful authentication
- Unusual administrative configuration changes
Network Indicators:
- HTTP POST requests to router IP on port 80/443 with specific payload
- Traffic patterns indicating router configuration changes
SIEM Query:
source="router_logs" AND (uri="/boafrm/formLogin" OR method="POST" AND data CONTAINS "getSanvas")🔗 References
- http://packetstormsecurity.com/files/156083/Realtek-SDK-Information-Disclosure-Code-Execution.html
- http://seclists.org/fulldisclosure/2020/Jan/36
- http://seclists.org/fulldisclosure/2020/Jan/38
- https://sploit.tech
- http://packetstormsecurity.com/files/156083/Realtek-SDK-Information-Disclosure-Code-Execution.html
- http://seclists.org/fulldisclosure/2020/Jan/36
- http://seclists.org/fulldisclosure/2020/Jan/38
- https://sploit.tech
