Worm:W32/Autorun.KD

Classification

Category :

Malware

Type :

Worm

Aliases :

Worm.Win32.Autorun.svl

Summary

Autorun.KD is delivered as a spam email attachment, using the attachment name of "abrechnung.zip".The zip file contains two files: abrechnung.lnk and scann.a. The former is a Windows Shortcut and the latter is a copy of the malware.

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

Execution

Running the abrechnung.lnk file will execute scann.a, the actual malware file. The worm will create the directory %programfiles%\Microsoft Common, then create a copy of itself as %programfiles%\Microsoft Common\svchost.exe and delete the original scann.a file.The worm will then use http://www.microsoft.com to check for the presence of a usable Internet connection and will then attempt to connect to two additional websites, using information on the infected machine as parameters. The websites connected to may respond with further download locations, or additional instructions for the malware.

Registry

On execution, the worm will create a registry entry that allows it to execute whenever explorer.exe is launched.

Propagation

Autorun.KD can spread via Windows autorun feature and by copying itself onto other drive media:

[autorun] open=system.exe shellexecute=system.exe shell\Open\command=system.exe shell=Explore
 

File System Changes

Create these directories:

  • %programfiles%\Microsoft Common

Network Connections

Attempts to connect to:

  • https://univnext.cn/[...].php?
  • https://cjusbciw123.com/[...].php?

Registry Modifications

Creates these keys:

  • HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\explorer.exe Debugger = "C:\Program Files\Microsoft Common\svchost.exe