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Published Nov 29, 2010 | Updated Sep 15, 2017

Worm:Win32/Katar.A

Detected by Microsoft Defender Antivirus

Aliases: Trojan.Win32.Autoit.abl (Kaspersky) DR/Autoit.abl.3 (Avira) Trojan.MulDrop1.52399 (Dr.Web) Win32/AutoRun.Autoit.BJ (ESET) Email-Worm.Win32.Agent (Ikarus) W32/Sohanat.AS.worm (Panda) Trojan.Win32.Generic.51FE29EC (Rising AV) Sus/UnkPack-C (Sophos) Trojan.Win32.Generic!SB.0 (Sunbelt Software) W32.Harakit (Symantec) WORM_HARAKIT.HNY (Trend Micro)

Summary

Worm:Win32/Katar.A is a detection for malware that spreads by email, and copies itself to network shares and removable drives. The worm also disables services and closes application windows containing certain strings.
To detect and remove this threat and other malicious software that may be installed in your computer, run a full-system scan with an up-to-date antivirus product such as the following:
 
 
For more information on antivirus software, see http://www.microsoft.com/windows/antivirus-partners/.
 
Recovering from recurring infections on a network
The following additional steps may need to be taken to completely remove this threat from an infected network, and to stop infections from recurring from this and other similar types of network-spreading malware:
 
  1. Ensure that an antivirus product is installed on ALL computers connected to the network that can access or host shares.
  2. Ensure that all available network shares are scanned with an up-to-date antivirus product.
  3. Restrict permissions as appropriate for network shares on your network. For more information on simple access control, please see: http://technet.microsoft.com/library/bb456977.aspx.
  4. Remove any unnecessary network shares or mapped drives.
 
Note: Additionally it may be necessary to temporarily change the permission on network shares to read-only until the disinfection process is complete.
 
Enabling registry editor
This threat may modify the computer to prevent Registry Editor from running. To enable Registry Editor in your computer, please do the following:
 
  1. Run a command prompt. Click Start>Run and type cmd.
  2. In the command prompt, type the following as is and press Enter:
    reg.exe add HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\System /v DisableRegistryTools /t REG_DWORD /d 0 /f
  3. Type exit at the command prompt.
 
Disable Autorun functionality
This threat attempts to spread via removable drives on computers that support Autorun functionality. This is a particularly common method of spreading for many current malware families. For information on disabling Autorun functionality, please see the following article:
 
Additional remediation instructions for Worm:Win32/Katar.A
This threat may make lasting changes to a computer’s configuration that are NOT restored by detecting and removing this threat. For more information on returning an infected computer to its pre-infected state, please see the following article/s: 
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