CVE-2021-42542
📋 TL;DR
This directory traversal vulnerability allows attackers to access files outside the intended backup folder structure by manipulating path sequences. It affects industrial control systems using specific versions of the affected product's software. Attackers could potentially read sensitive system files or write malicious files to unauthorized locations.
💻 Affected Systems
- Specific industrial control system software (check vendor advisory for exact product names)
📦 What is this software?
Wireless 1410d Gateway Firmware by Emerson
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise through arbitrary file read/write, potentially leading to data exfiltration, system manipulation, or ransomware deployment.
Likely Case
Unauthorized access to sensitive configuration files, backup data, or system logs, potentially enabling further attacks.
If Mitigated
Limited impact with proper network segmentation and access controls preventing exploitation attempts.
🎯 Exploit Status
Directory traversal vulnerabilities are typically straightforward to exploit once identified, requiring path manipulation techniques.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check vendor-specific patch version in ICSA-21-278-02 advisory
Vendor Advisory: https://us-cert.cisa.gov/ics/advisories/icsa-21-278-02
Restart Required: Yes
Instructions:
1. Review ICSA-21-278-02 advisory for affected product list
2. Contact vendor for specific patch availability
3. Apply vendor-provided patch following vendor instructions
4. Restart affected systems as required
5. Verify patch application
🔧 Temporary Workarounds
Disable backup functionality
windowsTemporarily disable backup features until patch can be applied
Vendor-specific configuration commands to disable backup services
Restrict backup folder permissions
windowsApply strict file system permissions to backup directories
icacls "C:\backup\path" /deny Everyone:(OI)(CI)F
Set-ACL commands for specific user restrictions
🧯 If You Can't Patch
- Implement network segmentation to isolate affected systems from untrusted networks
- Apply strict access controls limiting who can initiate backup operations
🔍 How to Verify
Check if Vulnerable:
Check software version against vendor's affected version list in ICSA-21-278-02Check Version:
Vendor-specific version check command (check product documentation)Verify Fix Applied:
Verify patch version installation and test backup functionality with path traversal attempts📡 Detection & Monitoring
Log Indicators:
- Unusual backup operations with path sequences containing ../ or ..\
- Failed backup attempts with path traversal patterns
- Access to files outside expected backup directories
Network Indicators:
- Unusual backup-related network traffic patterns
- Connections to backup services from unauthorized sources
SIEM Query:
source="backup_logs" AND (message="*../*" OR message="*..\\*")