CVE-2021-43456
📋 TL;DR
CVE-2021-43456 is an unquoted service path vulnerability in Rumble Mail Server that allows local attackers to escalate privileges by placing a malicious executable in a service path directory. This affects systems running Rumble Mail Server 0.51.3135 where an attacker has local access. The vulnerability enables execution of arbitrary code with SYSTEM privileges.
💻 Affected Systems
- Rumble Mail Server
📦 What is this software?
Rumble Mail Server by Rumble Mail Server Project
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with SYSTEM privileges, allowing complete control over the server, data theft, and lateral movement within the network.
Likely Case
Local privilege escalation to SYSTEM, enabling installation of malware, persistence mechanisms, and credential harvesting.
If Mitigated
Limited impact if proper access controls prevent local users from writing to service path directories.
🎯 Exploit Status
Exploit requires local access and ability to write to service path directory. Public exploit code available on Exploit-DB and GitHub.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not available
Vendor Advisory: Not available
Restart Required: No
Instructions:
No official patch available. Consider upgrading to a newer version if available or implementing workarounds.
🔧 Temporary Workarounds
Quote Service Path
windowsModify the service configuration to use quoted paths in the service executable path
sc config "RumbleService" binPath= "\"C:\Program Files\Rumble\RumbleService.exe\""
Restrict Directory Permissions
windowsRemove write permissions for non-administrative users on the Rumble installation directory
icacls "C:\Program Files\Rumble" /deny Users:(OI)(CI)W
🧯 If You Can't Patch
- Implement strict access controls to prevent local users from writing to service path directories
- Monitor for unauthorized file creation in Rumble installation directories
🔍 How to Verify
Check if Vulnerable:
Check if Rumble Mail Server version is 0.51.3135 and service path is unquoted: sc qc RumbleServiceCheck Version:
Check program version in Control Panel or registry: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\UninstallVerify Fix Applied:
Verify service path is quoted and directory permissions restrict write access to non-admins📡 Detection & Monitoring
Log Indicators:
- Windows Event Logs showing service path modifications
- Unexpected file creation in Rumble directories
- Process creation from unusual locations
Network Indicators:
- Not applicable - local exploitation only
SIEM Query:
EventID=7045 AND ServiceName="RumbleService" OR ProcessCreation WHERE ImagePath contains "Rumble" AND NOT ImagePath starts with '"'