CVE-2021-27445
📋 TL;DR
Mesa Labs AmegaView versions 3.0 and prior have insecure file permissions that allow local attackers to modify critical files and escalate privileges on the device. This affects industrial control systems using these specific versions of the AmegaView software.
💻 Affected Systems
- Mesa Labs AmegaView
📦 What is this software?
Amegaview by Mesalabs
⚠️ Risk & Real-World Impact
Worst Case
An attacker with local access could gain full administrative control of the device, potentially compromising the entire industrial control system and enabling further attacks on connected systems.
Likely Case
A malicious insider or compromised user account could escalate privileges to administrator level, allowing unauthorized configuration changes, data access, or disruption of monitoring functions.
If Mitigated
With proper access controls and network segmentation, impact would be limited to the local device only, preventing lateral movement to other systems.
🎯 Exploit Status
Exploitation requires local access to the system. The vulnerability involves insecure file permissions that can be manipulated by users with standard access.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Version 3.1 or later
Vendor Advisory: https://us-cert.cisa.gov/ics/advisories/icsa-21-147-03
Restart Required: Yes
Instructions:
1. Contact Mesa Labs for updated software. 2. Backup current configuration. 3. Install AmegaView version 3.1 or later. 4. Restart the system. 5. Verify proper operation.
🔧 Temporary Workarounds
Restrict File Permissions
windowsManually adjust file permissions on critical AmegaView files to restrict write access to administrators only.
icacls "C:\Program Files\AmegaView\*" /inheritance:r /grant:r "Administrators:(OI)(CI)F" /grant:r "SYSTEM:(OI)(CI)F" /remove:g "Users"
icacls "C:\ProgramData\AmegaView\*" /inheritance:r /grant:r "Administrators:(OI)(CI)F" /grant:r "SYSTEM:(OI)(CI)F" /remove:g "Users"
Network Segmentation
allIsolate AmegaView systems from general network access and restrict to necessary industrial control network segments only.
🧯 If You Can't Patch
- Implement strict access controls to limit who can log into AmegaView systems.
- Monitor file permission changes and user privilege escalation attempts on affected systems.
🔍 How to Verify
Check if Vulnerable:
Check AmegaView version in Help > About menu. If version is 3.0 or earlier, the system is vulnerable.Check Version:
Check Help > About in AmegaView application interfaceVerify Fix Applied:
Verify version is 3.1 or later in Help > About menu, and check that critical AmegaView files have proper permissions (only Administrators and SYSTEM have write access).📡 Detection & Monitoring
Log Indicators:
- Unexpected file permission changes in Windows security logs
- User privilege escalation events
- Unauthorized access attempts to AmegaView directories
Network Indicators:
- Unusual authentication patterns to AmegaView systems
- Lateral movement attempts from AmegaView systems
SIEM Query:
EventID=4672 OR EventID=4688 | where ProcessName contains "AmegaView" OR TargetObject contains "AmegaView"