CVE-2020-24307
📋 TL;DR
CVE-2020-24307 is a privilege escalation vulnerability in mRemoteNG v1.76.20 that allows attackers to execute arbitrary code with elevated privileges via a crafted executable file. This affects users running the vulnerable version of mRemoteNG on Windows systems. The vulnerability leverages improper privilege management to bypass security controls.
💻 Affected Systems
- mRemoteNG
📦 What is this software?
Mremoteng by Mremoteng
⚠️ Risk & Real-World Impact
Worst Case
Attackers gain SYSTEM-level privileges on the affected Windows machine, enabling complete system compromise, data theft, lateral movement, and persistence.
Likely Case
Local attackers escalate from standard user privileges to administrative privileges, allowing installation of malware, credential harvesting, and further network exploitation.
If Mitigated
With proper privilege separation and application control policies, impact is limited to the user context without administrative escalation.
🎯 Exploit Status
Exploit requires local access and ability to execute a crafted file. Public proof-of-concept code exists on Packet Storm Security and GitHub repositories.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: v1.76.21 and later
Vendor Advisory: https://github.com/mRemoteNG/mRemoteNG/issues/2338
Restart Required: Yes
Instructions:
1. Download latest mRemoteNG version from official repository. 2. Uninstall vulnerable version. 3. Install updated version. 4. Restart system to ensure clean state.
🔧 Temporary Workarounds
Remove vulnerable version
windowsUninstall mRemoteNG v1.76.20 and replace with alternative remote management tools
Control Panel > Programs > Uninstall a program > Select mRemoteNG > Uninstall
Restrict execution permissions
windowsApply application control policies to prevent execution of unauthorized binaries
Using Group Policy or Windows Defender Application Control to restrict mRemoteNG execution
🧯 If You Can't Patch
- Implement strict least-privilege access controls to limit user permissions
- Deploy endpoint detection and response (EDR) solutions to monitor for privilege escalation attempts
🔍 How to Verify
Check if Vulnerable:
Check mRemoteNG version in Help > About menu or examine installed programs list for version 1.76.20Check Version:
wmic product where name="mRemoteNG" get versionVerify Fix Applied:
Verify installed version is 1.76.21 or later in Help > About menu📡 Detection & Monitoring
Log Indicators:
- Windows Event Logs showing unexpected process creation with elevated privileges
- Security logs with privilege escalation events (Event ID 4672, 4688)
Network Indicators:
- Unusual outbound connections from mRemoteNG process to unknown destinations
SIEM Query:
source="windows_security" event_id=4672 OR event_id=4688 process_name="mRemoteNG.exe"🔗 References
- https://github.com/NyaMeeEain/Infrastructure-Assessment/blob/master/Privilege%20Escalation/Common%20Windows%20Privilege%20Escalation.md
- https://github.com/mRemoteNG/mRemoteNG/issues/2338
- https://packetstormsecurity.com/files/170794/mRemoteNG-1.76.20-Privilege-Escalation.html
- https://github.com/NyaMeeEain/Infrastructure-Assessment/blob/master/Privilege%20Escalation/Common%20Windows%20Privilege%20Escalation.md
- https://github.com/mRemoteNG/mRemoteNG/issues/2338
- https://packetstormsecurity.com/files/170794/mRemoteNG-1.76.20-Privilege-Escalation.html
