CVE-2021-22825
📋 TL;DR
This vulnerability allows attackers to gain elevated system privileges by tricking a privileged user into clicking a malicious URL that compromises security tokens. It affects Schneider Electric AP7xxxx, AP8xxx, and APDU9xxx devices with specific NMC2 and NMC3 firmware versions.
💻 Affected Systems
- AP7xxxx with NMC2
- AP8xxx with NMC2
- AP7xxx with NMC3
- AP8xxx with NMC3
- APDU9xxx with NMC3
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with administrative privileges, allowing complete control over affected devices and potential lateral movement within the network.
Likely Case
Unauthorized access to sensitive device configurations, potential data exposure, and disruption of industrial control operations.
If Mitigated
Limited impact if proper network segmentation and user privilege controls are implemented, though some information exposure may still occur.
🎯 Exploit Status
Exploitation requires user interaction but no technical complexity beyond crafting malicious URL.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: NMC2: V6.9.7 or later; NMC3: V1.1.0.4 or later for AP7xxx/AP8xxx, V1.0.0.29 or later for APDU9xxx
Vendor Advisory: https://download.schneider-electric.com/files?p_Doc_Ref=SEVD-2021-348-04
Restart Required: Yes
Instructions:
1. Download appropriate firmware update from Schneider Electric website. 2. Backup current configuration. 3. Apply firmware update following vendor instructions. 4. Restart device. 5. Verify successful update.
🔧 Temporary Workarounds
Restrict network access
allLimit device access to trusted networks only, preventing external attackers from delivering malicious URLs.
User awareness training
allTrain privileged users to avoid clicking unknown URLs and recognize phishing attempts.
🧯 If You Can't Patch
- Implement strict network segmentation to isolate affected devices from untrusted networks
- Apply principle of least privilege to user accounts and monitor privileged user activities
🔍 How to Verify
Check if Vulnerable:
Check device firmware version via web interface or CLI; compare against affected versions listed in advisory.Check Version:
Check via device web interface or consult device documentation for version query commands.Verify Fix Applied:
Verify firmware version is updated to patched version and test that security tokens are properly protected.📡 Detection & Monitoring
Log Indicators:
- Unusual authentication attempts
- Privileged account activity from unexpected sources
- URL access logs showing suspicious links
Network Indicators:
- Unexpected outbound connections from affected devices
- Traffic patterns suggesting token compromise
SIEM Query:
Search for: 'privileged account' AND ('malicious URL' OR 'suspicious link') OR 'unexpected token generation'