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Virus:Worm/Yahos.mg
Date discovered:28/01/2011
Type:Worm
Subtype:BE9C85C24390BD527C57CC1AA59A4241
In the wild:Yes
Reported Infections:Medium
Distribution Potential:Low to medium
Damage Potential:Medium
Static file:Yes
File size:94.208 Bytes
VDF version:7.10.08.76
IVDF version:7.11.02.17 - Friday, January 28, 2011

 General Method of propagation:
   • Messenger


Aliases:
   •  Mcafee: W32/Sdbot.bfr!a
   •  Kaspersky: IM-Worm.Win32.Yahos.mg
   •  TrendMicro: WORM_YAHOS.AM
   •  F-Secure: Worm:W32/Slenfbot.AGV
   •  Sophos: W32/Agent-QEF
   •  Microsoft: Worm:Win32/Slenfbot.AKD
   •  Panda: W32/Lolbot.Q.worm
   •  VirusBuster: Worm.Yahos!uzwHWUDAUIg
   •  DrWeb: BackDoor.IRC.Bot.763
   •  Norman: W32/Slenfbot.T


Platforms / OS:
   • Windows 95
   • Windows 98
   • Windows 98 SE
   • Windows ME
   • Windows 2000
   • Windows XP
   • Windows 2003
   • Windows Vista
   • Windows Server 2008
   • Windows 7


Side effects:
   • Drops files
   • Lowers security settings
   • Records keystrokes
   • Registry modification
   • Opens website in web browser

 Files It copies itself to the following location:
   • %WINDIR%\nvsvc32.exe



The following files are created:

– Non malicious files:
   • %WINDIR%\ndl.dl
   • %WINDIR%\wiybr.png
   • %WINDIR%\wibrf.jpg




It tries to execute the following files:

– Filename:
   • %SYSDIR%\net.exe


– Filename:
   • %SYSDIR%\netsh.exe
using the following command line arguments: firewall add allowedprogram 1.exe 1 ENABLE


– Filename:
   • %SYSDIR%\ntvdm.exe


– Filename:
   • %SYSDIR%\sc.exe
using the following command line arguments: config wuauserv start= disabled


– Filename:
   • %SYSDIR%\sc.exe
using the following command line arguments: config MsMpSvc start= disabled


– Filename:
   • %WINDIR%\nvsvc32.exe


– Filename:
   • %WINDIR%\explorer.exe
using the following command line arguments: http://browseusers.myspa**********.com/Browse/Browse.aspx

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

– [HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
   • "NVIDIA driver monitor"="%WINDIR%\nvsvc32.exe"

– [HKCU\Software\Microsoft\Windows\CurrentVersion\Run]
   • "NVIDIA driver monitor"="%WINDIR%\nvsvc32.exe"

– [HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Terminal Server\
   Install\Software\Microsoft\Windows\CurrentVersion\Run]
   • "NVIDIA driver monitor"="%WINDIR%\nvsvc32.exe"



It creates the following entry in order to bypass the Windows XP firewall:

– [HKLM\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\
   FirewallPolicy\StandardProfile\AuthorizedApplications\List]
   • "%malware execution directory%\%executed
      file%
"="%WINDIR%\nvsvc32.exe:*:Enabled:NVIDIA driver monitor"



The following registry keys are changed:

– [HKCR\TypeLib\%CLSID%\1.1\0\win32]
   New value:
   • "(Default)"="oleacc.dll"

Lower security settings from Internet Explorer:

– [HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings\
   ZoneMap]
   Old value:
   • "ProxyBypass"=%user defined settings%
   • "IntranetName"=%user defined settings%
   • "UNCAsIntranet"=%user defined settings%
   New value:
   • "ProxyBypass"=dword:00000001
   • "IntranetName"=dword:00000001
   • "UNCAsIntranet"=dword:00000001

– [HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings]
   Old value:
   • "MigrateProxy"=%user defined settings%
   • "ProxyEnable"=%user defined settings%
   New value:
   • "MigrateProxy"=dword:00000001
   • "ProxyEnable"=dword:00000000

– [HKEY_CURRENT_CONFIG\Software\Microsoft\windows\CurrentVersion\
   Internet Settings]
   Old value:
   • "ProxyEnable"=%user defined settings%
   New value:
   • "ProxyEnable"=dword:00000000

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

– Yahoo Messenger


Message
The sent message looks like the following:

   • %message text% :D http://yrtadelozie**********

 IRC To deliver system information and to provide remote control it connects to the following IRC Server:

Server: %IRC server%
Port: 1234
Server password: xxx
Channel: #!nn!**********
Nickname: NEW-[GBR|00|**********|%random numbers%]


– Furthermore it has the ability to perform actions such as:
    • connect to IRC server
    • disconnect from IRC server
    • Join IRC channel

 Miscellaneous Internet connection:

It queries with the following names:
   • astro.ic.**********.uk
   • ale.pakibi**********.com
   • versat**********.com
   • journalofaccountan**********.com
   • transnationa**********.org
   • mas.0730**********.com
   • api.albertoshisto**********.info
   • stayonti**********.info
   • www.shearm**********.com
   • insidehigher**********.com
   • ate.lacoctele**********.net
   • websitetraffics**********.com
   • qun.5**********.com
   • summer-uni-sw.**********.ch
   • shopsty**********.com
   • xxx.stopklat**********.pl
   • unclef**********.com
   • mcsp.lvengi**********.com
   • www.facebo**********.com
   • browseusers.myspa**********.com
   • www.myspa**********.com
   • x.myspacec**********.com
   • deirdremcclosk**********.org
   • journals.l**********.com
   • middleastpo**********.org
   • mas.archiv**********.info
   • scribbidyscru**********.com
   • mas.mtim**********.com
   • ols.systemofado**********.com
Accesses internet resources:
   • http://www.facebo**********.com/home.php;
      http://www.facebo**********.com/login.php;
      http://browseuse**********.myspace.com/Browse/Browse.aspx;
      http://www.myspa**********.com/browse/people;
      http://www.myspa**********.com/help/browserunsupported;
      http://x.myspace**********.com/modules/splash/static/img/cornersSheet.png;
      http://x.myspacec**********.com/images/BrowserUpgrade/bg_infobox.jpg;
      http://x.myspace**********.com/images/BrowserUpgrade/icon_information.gif;
      http://x.myspace**********.com/images/BrowserUpgrade/bg_browserSection.jpg;
      http://x.myspace**********.com/images/BrowserUpgrade/browserLogos_med.jpg;
      http://174.37.200.**********/index.php

 File details Programming language:
The malware program was written in MS Visual C++.


Compilation date:
Date: 27/01/2011
Time: 15:03:49

Description inserted by Alexander Bauer on Monday, January 31, 2011
Description updated by Alexander Bauer on Monday, January 31, 2011

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