CVE-2021-41451
📋 TL;DR
A cache poisoning vulnerability in TP-Link Archer AX10 v1 routers allows remote attackers to manipulate HTTP responses by sending specially crafted requests. This affects users with unpatched firmware who have the web interface exposed. Attackers can poison caches to redirect users to malicious sites or serve harmful content.
💻 Affected Systems
- TP-Link Archer AX10 v1
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers could redirect all router web interface traffic to malicious sites, potentially stealing credentials, installing malware, or performing man-in-the-middle attacks on router administration.
Likely Case
Cache poisoning leading to users being redirected to phishing sites or served malicious content when accessing the router's web interface.
If Mitigated
Limited impact with proper network segmentation and firewall rules preventing external access to router web interface.
🎯 Exploit Status
Exploitation requires crafting specific HTTP requests but no authentication is needed. Cache poisoning attacks require additional conditions to be effective.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: V1_211117 or later
Vendor Advisory: https://www.tp-link.com/us/support/download/archer-ax10/v1/#Firmware
Restart Required: Yes
Instructions:
1. Download firmware V1_211117 or later from TP-Link support site. 2. Log into router web interface. 3. Navigate to System Tools > Firmware Upgrade. 4. Upload the firmware file. 5. Wait for upgrade to complete and router to reboot.
🔧 Temporary Workarounds
Disable Remote Management
allPrevent external access to router web interface
Restrict Web Interface Access
allUse firewall rules to limit access to router administration
🧯 If You Can't Patch
- Isolate router management interface to trusted internal network only
- Implement network segmentation to limit potential attack surface
🔍 How to Verify
Check if Vulnerable:
Check firmware version in router web interface under System Tools > Firmware Upgrade. If version is earlier than V1_211117, device is vulnerable.Check Version:
Check via web interface or use nmap/curl to query router versionVerify Fix Applied:
Confirm firmware version shows V1_211117 or later after upgrade.📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP/0.9 response patterns
- Multiple malformed HTTP requests to router web interface
Network Indicators:
- HTTP requests with crafted headers targeting router IP
- Unexpected HTTP/0.9 responses from router
SIEM Query:
source_ip=router_ip AND (http_version="0.9" OR http_status_code=0)