Summary
A remote administration tool (RAT) that bypasses the security features of a program, computer or network to give unauthorized access or control to its user.
Removal
Based on the settings of your F-Secure security product, it will either move the file to the quarantine where it cannot spread or cause harm, or remove it.
A False Positive is when a file is incorrectly detected as harmful, usually because its code or behavior resembles known harmful programs. A False Positive will usually be fixed in a subsequent database update without any action needed on your part. If you wish, you may also:
Check for the latest database updates
First, check if your F-Secure security program is using the latest updates, then try scanning the file again.
Submit a sample
After checking, if you still believe the file is incorrectly detected, you can submit a sample of it for re-analysis.
Note: If the file was moved to quarantine, you need to collect the file from quarantine before you can submit it.
Exclude a file from further scanning
If you are certain that the file is safe and want to continue using it, you can exclude it from further scanning by the F-Secure security product.
Note: You need administrative rights to change the settings.
Technical Details
This backdoor program attempts to connect to a remote IRC server. It also attempts a Denial-of-Service (DoS) exploit on any machines it finds with an open Microsoft-ds (Directory Service) port.
Installation
During installation, the following files are created:
- %windir%\system\wmisvr.exe - Copy of the backdoor
- %windir%\system32\drivers\sysdrv32.sys - Detected as Worm.Win32.AutoRun.ezt
Activity
While active, the backdoor attempts to connect to a remote IRC server:
- sec.republicofskorea.info:8084/TCP
The backdoor also iterates the IP address and looks for available systems with an open Microsoft-ds port (specifically, tcp 445). If a vulnerable machine is discovered, the backdoor breaches the targeted machine's Windows Firewall, a form of Denial-of-Service (DoS) exploit similar to the notorious MS04-011 vulnerability.To protect the backdoor, the WMISRV Service is stopped when the debugger program Ollydbg is launched; this protective action makes the debugging process more difficult.
Registry
The backdoor edits the Windows Firewall Policy, to allow it to function as an authorized application.
- HKLM\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List C:\WINDOWS\system\wmisvr.exe = C:\WINDOWS\system\wmisvr.exe:*:Microsoft Enabled
It also sets two malware launch points as services:
- HKLM\System\CurrentControlSet\Services\WMISRV ImagePath = "C:\WINDOWS\system\wmisvr.exe" DisplayName = WMI Servicer Description = Auto-Syncs Patches and Hotfixes
- HKLM\System\CurrentControlSet\Services\sysdrv32 ImagePath = \??\C:\WINDOWS\system32\drivers\sysdrv32.sys DisplayName = Play Port I/O Driver
The following mutex name is used by wmisvr.exe:
- ScnBx
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