CVE-2021-38466
📋 TL;DR
This vulnerability allows attackers to inject malicious scripts via the help page of InHand Networks IR615 routers, which are then executed in victims' browsers. It affects users of IR615 router versions 2.3.0.r4724 and 2.3.0.r4870, potentially leading to session hijacking or credential theft.
💻 Affected Systems
- InHand Networks IR615 Router
📦 What is this software?
Ir615 Firmware by Inhandnetworks
Ir615 Firmware by Inhandnetworks
⚠️ Risk & Real-World Impact
Worst Case
An attacker could steal session cookies, redirect users to malicious sites, or perform actions on behalf of authenticated users, leading to full compromise of router management or network access.
Likely Case
Attackers trick users into clicking malicious links, resulting in stolen credentials or session tokens for router administration.
If Mitigated
With input validation and output encoding, the attack is prevented, and no code execution occurs in browsers.
🎯 Exploit Status
Exploitation requires tricking a user into clicking a crafted link, but no authentication is needed to trigger the vulnerability.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check vendor for updated firmware beyond affected versions
Vendor Advisory: https://us-cert.cisa.gov/ics/advisories/icsa-21-280-05
Restart Required: Yes
Instructions:
1. Access the router's admin interface. 2. Navigate to firmware update section. 3. Download and apply the latest firmware from InHand Networks. 4. Reboot the router after update.
🔧 Temporary Workarounds
Disable help page access
linuxRestrict access to the help page via firewall rules or router configuration to prevent exploitation.
iptables -A INPUT -p tcp --dport 80 -m string --string 'help' --algo bm -j DROP
Implement web application firewall
allDeploy a WAF to filter and block malicious script injections targeting the help page.
🧯 If You Can't Patch
- Isolate the router on a segmented network to limit exposure and potential impact.
- Educate users to avoid clicking suspicious links and monitor for unusual network activity.
🔍 How to Verify
Check if Vulnerable:
Check the router firmware version via admin interface; if it is 2.3.0.r4724 or 2.3.0.r4870, it is vulnerable.Check Version:
ssh admin@router_ip show version or check via web admin interfaceVerify Fix Applied:
After updating, confirm the firmware version has changed and test the help page with safe payloads to ensure scripts are not executed.📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP requests to help page with script tags or encoded payloads in logs
Network Indicators:
- Spikes in traffic to router's help page from external IPs
SIEM Query:
source="router_logs" AND url="*help*" AND (payload="<script>" OR payload="javascript:")