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F-Secure Malware Information Pages: Virus:W32/Drowor.A
[Summary] | [Detailed Description] | [Detection]

Name : Virus:W32/Drowor.A
Alias:Virus.Win32.Drowor.a, Drowor.a
Type:Virus
Category:Malware
Platform:Win32
Radar

Summary
Drowor.A is a Windows file appending virus that infects executables in all drives found including network drives.
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Detailed Description
Drowor.A is a Windows file appending virus that infects executables in all drives found including network drives.

Upon execution, this virus checks to see if it is already running in memory by elevating its privileges and enumerating currently running processes on the affected machine.

It then creates and executes a copy of itself as:

  • %windows%\system\internat.exe.

It drops a hidden copy of itself, setup.exe, in the root directory of discovered drives. This includes network drives.
It creates an autorun.inf alongside of this setup.exe that may trigger and execute the file.
It Infects by appending itself in Windows executables, adding a section named ".ice" in the infected files.

Drowor.A creates a text file list of Windows executables in the discovered drives to a hard-coded path:

  • C:\WINDOWS\win.log

Drowor.A attempts to accesses a file from:

  • http://mm.21380.com/[Removed].txt

The URL is currently unavailable.
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Detection

F-Secure Anti-Virus detects this malware with the following updates:

[FSAV_Database_Version]

Version = 2007-03-11_01.
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F-Secure Corporation

Last Modified: March 12, 2007