CVE-2021-22748
📋 TL;DR
This path traversal vulnerability in Schneider Electric's C-Bus Toolkit and C-Gate Server allows attackers to write files outside intended directories, potentially leading to remote code execution. Affected systems include C-Bus Toolkit versions 1.15.9 and earlier, and C-Gate Server versions 2.11.7 and earlier. Attackers could exploit this to gain unauthorized access and control over affected systems.
💻 Affected Systems
- C-Bus Toolkit
- C-Gate Server
📦 What is this software?
C Bus Toolkit by Schneider Electric
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, data theft, and potential lateral movement within the network
Likely Case
Unauthorized file writes leading to service disruption, data manipulation, or privilege escalation
If Mitigated
Limited impact with proper network segmentation and access controls preventing exploitation
🎯 Exploit Status
Path traversal vulnerabilities are typically straightforward to exploit once details are known
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: C-Bus Toolkit > 1.15.9, C-Gate Server > 2.11.7
Vendor Advisory: http://download.schneider-electric.com/files?p_Doc_Ref=SEVD-2021-103-01
Restart Required: Yes
Instructions:
1. Download updated versions from Schneider Electric portal. 2. Backup configurations. 3. Install updates following vendor documentation. 4. Restart services. 5. Verify functionality.
🔧 Temporary Workarounds
Network Segmentation
allIsolate affected systems from untrusted networks and internet
Access Control Restrictions
allImplement strict firewall rules limiting access to necessary IPs only
🧯 If You Can't Patch
- Implement strict network segmentation to isolate affected systems
- Deploy application firewalls with path traversal detection rules
🔍 How to Verify
Check if Vulnerable:
Check installed version against affected versions: C-Bus Toolkit ≤ 1.15.9 or C-Gate Server ≤ 2.11.7Check Version:
Check version in application interface or installation directory propertiesVerify Fix Applied:
Verify installed version is C-Bus Toolkit > 1.15.9 or C-Gate Server > 2.11.7📡 Detection & Monitoring
Log Indicators:
- Unusual file write operations
- Path traversal patterns in file paths
- Unauthorized access attempts
Network Indicators:
- Unusual traffic to C-Bus/C-Gate ports
- File upload attempts with directory traversal patterns
SIEM Query:
source="c-bus" OR source="c-gate" AND (event="file_write" OR event="file_upload") AND path="*../*"