Virus:Worm/IM.Guap.a
Date discovered:22/08/2005
Type:Worm
In the wild:No
Reported Infections:Low
Distribution Potential:Low to medium
Damage Potential:Low to medium
Static file:Yes
File size:57.344 Bytes
MD5 checksum:64B2695C0F8B25A89581C25618E2096B
VDF version:6.31.1.154

 General Method of propagation:
   • Messenger


Aliases:
   •  Mcafee: W32/Generic.worm!p2p
   •  Kaspersky: IM-Worm.Win32.Guap.a
   •  Bitdefender: Win32.Worm.Guap.A


Platforms / OS:
   • Windows 95
   • Windows 98
   • Windows 98 SE
   • Windows NT
   • Windows ME
   • Windows 2000
   • Windows XP
   • Windows 2003


Side effects:
   • Blocks access to certain websites
   • Blocks access to security websites
   • Lowers security settings
   • Registry modification

 Files It copies itself to the following location:
   • %SYSDIR%\pkguard32.exe



The following file is created:

– %WINDIR%\hosts

 Registry The following registry key is added in order to run the process after reboot:

– [HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\RunServices]
   • PK Guard"="%SYSDIR%\pkguard32.exe"



The following registry keys are continuously in an infinite loop added in order to run the processes after reboot.

–  [HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
   • PK Guard"="%SYSDIR%\pkguard32.exe"

–  [HKCU\Software\Microsoft\Windows\CurrentVersion\Run]
   • PK Guard"="%SYSDIR%\pkguard32.exe"



The following registry keys are changed:

– [HKLM\SYSTEM\CurrentControlSet\Services\wuauserv]
   Old value:
   • "Start"=dword:00000002
   New value:
   • "Start"=dword:00000004

– [HKLM\SYSTEM\CurrentControlSet\Services\SharedAccess]
   Old value:
   • "Start"=dword:00000002
   New value:
   • "Start"=dword:00000004

 Messenger It is spreading via Messenger. The characteristics are described below:

– AIM Messenger
– Yahoo Messenger
– Windows Messenger


To:
All entries in the contact list.


Message
The sent message looks like the following:

   • It repeatedly sends the following line to all of the user's contacts:
     Hehe, take a look at this funny game %link%


%link%
While the wildcard is the following:
   • http://**********games.yaboo.dk/Monkye.exe

The URL then refers to a copy of the described malware. If the user downloads and executes this file the infection process will start again.

 Hosts The host file is modified as explained:

– Access to the following domains is effectively blocked:
   • www.symantec.com; symantec.com; securityresponse.symantec.com;
      sarc.com; www.sarc.com; www.sophos.com; sophos.com; www.mcafee.com;
      mcafee.com; liveupdate.symantecliveupdate.com; www.viruslist.com;
      viruslist.com; f-secure.com; www.f-secure.com; f-prot.com;
      www.f-prot.com; kaspersky.com; kaspersky-labs.com; www.avp.com;
      avp.com; www.kaspersky.com; www.networkassociates.com;
      networkassociates.com; www.ca.com; ca.com; mast.mcafee.com;
      my-etrust.com; www.my-etrust.com; download.mcafee.com;
      dispatch.mcafee.com; secure.nai.com; nai.com; www.nai.com;
      vil.nai.com; update.symantec.com; updates.symantec.com; us.mcafee.com;
      liveupdate.symantec.com; customer.symantec.com; rads.mcafee.com;
      trendmicro.com; www.trendmicro.com; housecall.trendmicro.com;
      pandasoftware.com; www.pandasoftware.com; www.trendmicro.com;
      free.grisoft.com; www.grisoft.com; grisoft.com; clamav.net;
      www.clamav.net; free-av.com; www.free-av.com; www.avast.com;
      avast.com; cert.org; www.cert.org; www.microsoft.com; microsoft.com;
      www.virustotal.com; virustotal.com; update.microsoft.com;
      windowsupdate.microsoft.com




The modified host file will look like this:


 Process termination  List of services that are disabled:
   • Internet Connection Firewall (ICF) / Internet Connection Sharing (ICS)
   • Automatic Updates

 Backdoor The following port is opened:

– %SYSDIR%\pkguard32.exe on a random UDP port

 File details Programming language:
 The malware program was written in Visual Basic.

Description inserted by Andrei Gherman on Tuesday, August 23, 2005
Description updated by Oliver Auerbach on Wednesday, September 7, 2005

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