Threat Descriptons



Category :


Type :


Aliases :



Trojan:W32/Delf.AOO is a trojan. This malware uses a hidden browser process (e.g. iexplorer.exe) to hide itself from the systems' process list. It terminates antivirus applications by searching for antivirus company strings in all application window title headers.


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

Upon execution, the malware detected asTrojan.Win32.Delf.aoo will create the following files:

  • %windir%\system32\zsmscc071031.exe
  • %windir%\zsmscc16.ini
  • %windir%\system32\zsmscc071031.dll
  • %windir%\system32\zsmscc32.dll

Note: zsmscc071031.exe is a copy of the original file.After the trojan's file is started by the user, it installs itself to the system by copying its file to the Windows folder.It also creates a startup key value in the Registry for the copied file. This is done to ensure that the trojan's file is started every time Windows boots. The startup key value is created under the following Registry key:

  • HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer\runzsmscc = rundll32.exe C:\WINDOWS\system32\zsmscc071006.dll mymain

Furthermore, Trojan.Win32.Delf.aoo launches an instance of Microsoft Internet Explorer as a hidden process with its code is injected into the process.After hiding itself on the system, it will download these files depending on the variant:

  • https://j[removed]
  • https://a[removed]
  • https://a[removed]


This trojan terminates applications that have the following text strings in their application window title headers:

  • 360safe
  • duba
  • kaspersky
  • mcafee
  • nod32
  • rising
  • Symantec AntiVirus
More Support


Ask questions in our Community .

User Guides

Check the user guide for instructions.

Contact Support

Chat with or call an expert.

Submit a Sample

Submit a file or URL for analysis.