CVE-2021-22656
📋 TL;DR
CVE-2021-22656 is a directory traversal vulnerability in Advantech iView that allows attackers to read sensitive files outside the intended directory. This affects organizations using Advantech iView versions before 5.7.03.6112 for industrial control system monitoring and management.
💻 Affected Systems
- Advantech iView
📦 What is this software?
Iview by Advantech
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise through reading configuration files containing credentials, followed by lateral movement within industrial control networks.
Likely Case
Unauthorized access to sensitive configuration files, potentially exposing credentials, network information, and system details.
If Mitigated
Limited impact with proper network segmentation and access controls preventing external access to vulnerable systems.
🎯 Exploit Status
Directory traversal vulnerabilities are simple to exploit with basic HTTP requests using ../ sequences.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: v5.7.03.6112
Vendor Advisory: https://us-cert.cisa.gov/ics/advisories/icsa-21-040-02
Restart Required: Yes
Instructions:
1. Download iView v5.7.03.6112 or later from Advantech support portal. 2. Backup current configuration. 3. Install the update following vendor instructions. 4. Restart the iView service.
🔧 Temporary Workarounds
Network Segmentation
allIsolate iView systems from untrusted networks and internet access
Web Application Firewall
allDeploy WAF with directory traversal protection rules
🧯 If You Can't Patch
- Implement strict network access controls to limit iView access to authorized IPs only
- Monitor for unusual file access patterns and ../ sequences in web server logs
🔍 How to Verify
Check if Vulnerable:
Check iView version in web interface or installation directory. Versions below 5.7.03.6112 are vulnerable.Check Version:
Check web interface login page or installation directory for version informationVerify Fix Applied:
Confirm version is 5.7.03.6112 or higher and test directory traversal attempts return proper errors.📡 Detection & Monitoring
Log Indicators:
- HTTP requests containing ../ sequences
- Access to unexpected file paths in web logs
- Failed attempts to access system files
Network Indicators:
- HTTP requests with directory traversal payloads to iView endpoints
- Unusual file downloads from iView server
SIEM Query:
source="iView_logs" AND (uri="*../*" OR uri="*..\\*" OR status=200 AND uri="*.config" OR uri="*.ini")