CVE-2025-2767
📋 TL;DR
This critical vulnerability in Arista NG Firewall allows remote attackers to execute arbitrary code with root privileges by exploiting a cross-site scripting flaw in User-Agent header processing. Attackers can inject malicious scripts that execute when the firewall processes HTTP requests, requiring minimal user interaction. Organizations using affected Arista NG Firewall versions are at risk.
💻 Affected Systems
- Arista NG Firewall
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with root-level access, allowing attackers to steal credentials, pivot to internal networks, deploy ransomware, or establish persistent backdoors.
Likely Case
Remote code execution leading to firewall configuration changes, network traffic interception, credential harvesting, and lateral movement within the network.
If Mitigated
Limited impact with proper network segmentation, but still potential for firewall compromise and limited data exposure.
🎯 Exploit Status
Exploitation requires sending specially crafted HTTP requests to the firewall. The ZDI-CAN-24407 identifier suggests this was discovered through coordinated vulnerability disclosure.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Arista security advisory for specific patched versions
Vendor Advisory: https://www.arista.com/en/support/advisories-notices/security-advisories
Restart Required: Yes
Instructions:
1. Check Arista security advisory for affected versions. 2. Download and apply the latest firmware/software update from Arista support portal. 3. Reboot the firewall to apply changes. 4. Verify the update was successful.
🔧 Temporary Workarounds
Input Validation Filtering
allImplement WAF or proxy rules to sanitize User-Agent headers before reaching the firewall
# Example WAF rule to block suspicious User-Agent patterns
# ModSecurity: SecRule REQUEST_HEADERS:User-Agent "[^\x20-\x7E]" "deny,status:400"
Network Segmentation
linuxRestrict access to firewall management interface to trusted IP addresses only
# Example firewall rule to restrict management access
iptables -A INPUT -p tcp --dport 443 -s 10.0.0.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP
🧯 If You Can't Patch
- Implement strict network access controls to limit who can reach the firewall management interface
- Deploy a web application firewall (WAF) in front of the firewall to filter malicious User-Agent headers
🔍 How to Verify
Check if Vulnerable:
Check firewall version against Arista's security advisory. Monitor for unusual User-Agent strings in firewall logs.Check Version:
show version (Arista CLI command)Verify Fix Applied:
Verify the firewall firmware version matches or exceeds the patched version specified in Arista's advisory.📡 Detection & Monitoring
Log Indicators:
- Unusual User-Agent strings containing script tags or JavaScript
- Multiple failed authentication attempts followed by successful login
- Unexpected configuration changes in firewall logs
Network Indicators:
- HTTP requests to firewall with malicious User-Agent headers
- Unusual outbound connections from firewall to external IPs
- Traffic patterns suggesting firewall compromise
SIEM Query:
source="firewall.log" AND (User-Agent="*<script>*" OR User-Agent="*javascript:*" OR User-Agent="*onerror=*" OR User-Agent="*alert(*")