Backdoor:W32/Bredavi

Classification

Type:Backdoor

Backdoor.Win32.Bredavi

Summary

A remote administration utility that bypasses normal security mechanisms to secretly control a program, computer or network.

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 is the Family Description for Backdoor:W32/Bredavi. Bredavi is a Remote Administration Tool (RAT) that can be exploited by remote users to gain control over a system on which the program is installed.

Installation process/actions

Upon its arrival in the system, the malware will check for its previous run on any of the targeted processes:

services.exe
iexplorer.exe
java.exe
javaw.exe
opera.exe

If the system is found clean with no traces that the malware has run on services.exe, the system will be infected then.

Using InterlockedExchange, the malware will hook the following functions:

From advapi32.dll - CryptEncrypt
From kernel32.dll - CreateFileW, GetFileAttributeExW
From ws2_32.dll - send, WSASend
From sks2xyz.dll (unknown dll that is believed to be its component) - vb_pfx_import
From User32.dll - GetWindowTextA

The malware will then look for iexplorer.exe, opera.exe, java.exe and javaw.exe, and injects itself in. It downloads a file from http://brendbar.cn/[...]n-bss.exe and saves it to '\\?\globalroot\systemroot\system32\ntfs_ext7.exe'.

It also makes a download from http://premiumbullets.cn/[...]php?id=!!. And, if "!killOS" string is found in the downloaded file, it terminates the following processes which are critical for the Windows operating system:

smss.exe
csrss.exe
lsass.exe
winlogon.exe

The malware modifies Windows host file to prevent the system from accessing domains that belongs to or affiliated with computer security companies.

Keylogger

The Bredavi malware contains a keylogger component, which surreptitiously monitors and stores all the strokes typed into the keyboard. For additional information on keylogger, please visit Encyclopedia: Keylogger.