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puowlan.dll - morphing worm

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#1 plumsauce


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Posted 11 November 2009 - 03:41 PM

Can anyone point me at information for this one?


puowlan.dll is located in system32 with SHR attributes. it is also locked, cannot be copied for later examination
157,271 bytes, there is also, sometimes, a file called "x", also in system32

the execution method:

a random new service is created with a plausible long name, but a random short name of exactly 9 characters, all lower case, no digits. the description text will be copied from a legitimate service that already exists on the system

there will also be matching legacy entries with a reference to a class id of {8ECC055D-047F-11D1-A537-0000F8153ED1}
this is EnumPropPages32, and runs via syssetup.dll

the execution method is via services.exe running the target dll, with a executable file parameter pointed at puowlan.dll

the symptoms:

if you interfere in the registry with the service entry, it will create a replacement entry, the entries are hidden until exposed with regedt32, not regedit.

netstat will be slow because it is being hooked

explorer.exe will be slow because it is also hooked

lots of connections on port 445

this is what i know, what i don't know is how to crush it.

i did it once, but, here's the kicker, it writes values to all versions of controlset(x)

the machine blue screened during further cleanup, and the selected controlset had the value in it.

the first move was a search for puowlan.dll on the search engines. no reference found.

anyone have suggestions?

Edited by plumsauce, 11 November 2009 - 03:46 PM.

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#2 plumsauce

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Posted 12 November 2009 - 12:44 AM

Any news?

Further searching on the guid suggests that it is similar to:


Backdoor.Formador [Symantec]
Trojan-Dropper.Win32.Delf.tp [Kaspersky Lab]
Trojan:Win32/Meredrop [Microsoft]
Trojan-Dropper.Win32.Delf [Ikarus]

The pattern fits, but this one seems newer.

searching on puowlan.dll only brings up this one thread, so it's not a known file name yet.

#3 garmanma


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Posted 14 November 2009 - 08:13 PM

We Need to check for Rootkits with RootRepeal
  • Download RootRepeal from the following location and save it to your desktop.
  • Extract RootRepeal.exe from the archive (If you did not use the "Direct Download" mirror).
  • Open Posted Image on your desktop.
  • Click the Posted Image tab.
  • Click the Posted Image button.
  • Check all seven boxes: Posted Image
  • Push Ok
  • Check the box for your main system drive (Usually C:), and press Ok.
  • Allow RootRepeal to run a scan of your system. This may take some time.
  • Once the scan completes, push the Posted Image button. Save the log to your desktop, using a distinctive name, such as RootRepeal.txt. Include this report in your next reply, please.


Please note: If Rootrepeal fails to run, try this step: Click Settings - Options. Set the Disk Access slider to High

Also try: right-click on rootrepeal.exe and rename it to tatertot.scr


Please download Win32kDiag.exe by AD and save it to your desktop.
alternate download 1
alternate download 2
  • This tool will create a diagnostic report
  • Double-click on Win32kDiag.exe to run and let it finish.
  • When it states Finished! Press any key to exit..., press any key on your keyboard to close the program.
  • A file called Win32kDiag.txt should be created on your Desktop.
  • Open that file in Notepad and copy/paste the entire contents (from Starting up... to Finished! Press any key to exit...) in your next reply.

:thumbsup: Go to Posted Image > Run..., then copy and paste this command into the open box: cmd
Click OK.
At the command prompt C:\>, copy and paste the following command and press Enter:
DIR /a/s %windir%\scecli.dll %windir%\netlogon.dll %windir%\eventlog.dll >Log.txt & START notepad Log.txt
A file called log.txt should be created on your Desktop.
Open that file and copy/paste the contents in your next reply.
Posted Image
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