CVE-2021-35296
📋 TL;DR
This vulnerability allows attackers to bypass authentication on PTCL HG150-Ub v3.0 routers by manipulating cookie values and response paths. Attackers can gain administrative access without valid credentials. This affects all users of the vulnerable router model.
💻 Affected Systems
- PTCL HG150-Ub
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete router compromise allowing attacker to reconfigure network settings, intercept traffic, install malware, or use the router as an attack platform.
Likely Case
Unauthorized administrative access leading to network configuration changes, DNS hijacking, or credential theft from connected devices.
If Mitigated
Limited impact if router is behind firewall with restricted administrative interface access.
🎯 Exploit Status
Public exploit code available on GitHub. Attack requires network access to the router's administrative interface.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Not available
Restart Required: No
Instructions:
No official patch available. Contact PTCL for firmware updates or replacement options.
🔧 Temporary Workarounds
Disable remote administration
allTurn off remote access to the router's administrative interface
Change default credentials
allChange default admin passwords even though bypass exists, as additional protection layer
🧯 If You Can't Patch
- Replace vulnerable router with updated model or different vendor
- Place router behind firewall with strict inbound rules blocking administrative interface access
🔍 How to Verify
Check if Vulnerable:
Check router model and firmware version via web interface or device label. If PTCL HG150-Ub v3.0, assume vulnerable.Check Version:
Login to router web interface and check System Information or About pageVerify Fix Applied:
Test authentication bypass using public PoC. If authentication required, vulnerability may be mitigated.📡 Detection & Monitoring
Log Indicators:
- Multiple failed login attempts followed by successful admin access
- Admin access from unusual IP addresses
- Configuration changes without proper authentication logs
Network Indicators:
- HTTP requests to admin panel with modified cookie values
- Unusual administrative traffic patterns
SIEM Query:
source="router_logs" AND (event="admin_login" AND result="success" AND NOT auth_method="password")