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Worm:Win32/Abfewsm.A


Worm:Win32/Abfewsm.A is a worm that spreads by placing copies of itself in the folder used for files to be written into CDs. It is capable of modifying a variety of system services as well as disabling Control Panel and registry editors. It may also modify some firewall settings.


What to do now

Manual removal is not recommended for this threat. To detect and remove this threat and other malicious software that may have been installed, run a full-system scan with an up-to-date antivirus product such as Microsoft Security Essentials, or the Microsoft Safety Scanner. For more information about using antivirus software, see http://www.microsoft.com/security/antivirus/av.aspx.
 
Enabling registry editor
This threat may modify the system to prevent Registry Editor from running. To reverse this effect on your system, 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.
Other recovery instructions
IMPORTANT: This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:
256986 Description of the Microsoft Windows Registry
322756 How to back up and restore the registry in Windows
 
WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.
 
To remove/modify the changes that Worm:Win32/Abfewsm.A has made to your computer, follow these steps:
 
1) Click Start and then click Run.
2) In the Open box, type regedit and then click OK.
3) Locate and then click on the following registry key:
HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
4) On the right panel, right-click on the following registry entry:
"NoControlPanel"
5) Select Delete and then click OK.
6) Locate and then click on the following registry key:
HKLM\SYSTEM\ControlSet001\Services\SharedAccess\Epoch
7) Right click on the subkey "Epoch" and select Delete. Select Yes.
8) Locate and click on the following registry key:
HKLM\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
9) On the right panel, right-click on the following registry entry:
"<system folder>\KHATRA.exe"
10) Select Delete and then click OK.
11) Close Registry Editor.
 
This threat may make lasting changes to an affected system’s configuration that will NOT be restored by detecting and removing this threat. For more information on returning an affected system to its pre-infected state, please see the following article/s: 

Threat behavior

Worm:Win32/Abfewsm.A is a worm that spreads by placing copies of itself in the folder used for files to be written into CDs. It is capable of modifying a variety of system services as well as disabling Control Panel and registry editors. It may also modify some firewall settings.
Installation
Worm:Win32/Abfewsm.A arrives in the system as a file that uses the Windows Explorer icon. It also creates a shortcut with no icon that points to itself:
 
  • <startup folder>\<no value>.LNK
 
Note - <startup folder> refers to a variable location that is determined by the malware by querying the Operating System. The default installation location for the Startup folder for Windows 9x, Me, NT, 2000, XP and 2003 is '%USERPROFILE%\Start Menu\Programs\Startup'. For Windows Vista, the default location is '%USERPROFILE%\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup'.

Worm:Win32/Abfewsm.A creates compressed file copies of itself in the Windows folder using the following names:
 
CyberWar.cab
fh_antivirussetup6534.cab
kavSetupEng3857.cab
mario675.cab
New WinRAR archive.cab
New WinRAR ZIP archive.cab
New WinZip File.cab
new-screamsaver.com.cab
supermodels.cab
Youtube.cab
 
It also copies itself to the following locations:
 
%windir%\KHATARNAKH.exe
%windir%\Xplorer.exe
%systemroot%\KHATRA.exe
%windir%\system\gHost.exe
<system folder>\KHATRA.exe
 
Note - <system folder> refers to a variable location that is determined by the malware by querying the Operating System. The default installation location for the System folder for Windows 2000 and NT is C:\Winnt\System32; and for XP and Vista is C:\Windows\System32.
 
It also creates the following files containing settings it uses:
 
%windir%\K.Backup\C_Drive_Documents and Settings_Administrator_Start Menu_Programs_Startup_desktop.ini.FUCKED
%windir%\K.Backup\C_Drive_Documents and Settings_All Users_Start Menu_Programs_Startup_desktop.ini.FUCKED
%windir%\K.Backup\C_Drive_Documents and Settings_All Users_Start Menu_Programs_Startup_whoami.lnk.FUCKED
 
Worm:Win32/Abfewsm.A creates the following registry entries to allow its copy to automatically run every time Windows starts:
 
Adds value: "PHIME2002A"
With data: "<system folder>\KHATRA.exe"
To subkey: HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
 
Adds value: "PHIME2002ASync"
With data: "%windir%\Xplorer.exe"
To subkey: HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
 
Adds value: "load"
With data: "<system folder>\KHATRA.exe"
To subkey: HKCU\Software\Microsoft\Windows NT\CurrentVersion\Windows
 
It also creates the following registry key, which contains its settings:
 
  • HKLM\SOFTWARE\KHATRA
 
Worm:Win32/Abfewsm.A also creates a job that runs itself every day at 09:00 by running the following commands in succession:
 
"AT /delete /yes" - deletes all previously scheduled jobs
"AT 09:00 /interactive /EVERY:m,t,w,th,f,s,su C:\WINDOWS\system32\KHATRA.exe" - creates a scheduled task to run its copy
 
It then adds the following registry entry so that its scheduled job recurs indefinitely:
 
Adds value: "AtTaskMaxHours"
With data: "0"
To subkey: HKLM\SYSTEM\CurrentControlSet\Services\Schedule
Spreads via…
Compact discs
Worm:Win32/Abfewsm.A copies itself as the following files to ensure that they are included when a CD is written to:
 
%AppData%\Microsoft\CD Burning\Administrator.exe
%AppData%\Microsoft\CD Burning\KHATRA.exe
%AppData%\Microsoft\CD Burning\New Folder(3).exe - copied as a hidden file
%AppData%\Microsoft\CD Burning\autorun.inf - initialization file that ensures that 'KHATRA.exe' is automatically executed when the CD is accessed and Autorun is enabled
 
As such, when a CD is written with the affected computer and then run from another computer, the worm copy automatically runs and infects that system.
Payload
Modifies system services
Worm:Win32/Abfewsm.A sets the following services to run automatically:
 
Remote Desktop Sharing service
Removable Storage service
Remote Desktop Help Session Manager
Terminal Server service
Telnet Server service
UPnP device hosting
 
It does this by modifying the system registry, respectively:
 
Adds value: "Start"
With data: "2"
To subkeys:
HKLM\SYSTEM\ControlSet001\Services\mnmsrvc
HKLM\SYSTEM\ControlSet001\Services\NtmsSvc
HKLM\SYSTEM\ControlSet001\Services\RDSessMgr
HKLM\SYSTEM\ControlSet001\Services\TermService
HKLM\SYSTEM\ControlSet001\Services\TlntSvr
HKLM\SYSTEM\ControlSet001\Services\upnphost
 
Worm:Win32/Abfewsm.A disables the following services:
 
Protected Storage service
Windows Security Center service
 
It does this by modifying the system registry, respectively:
 
Adds value: "Start"
With data: "4"
To subkeys:
HKLM\SYSTEM\ControlSet001\Services\ProtectedStorage
HKLM\SYSTEM\ControlSet001\Services\wscsvc
 
It also sets the Schedule service to run manually:
 
Adds value: "Start"
With data: "3"
To subkey: HKLM\SYSTEM\ControlSet001\Services\Schedule
 
Changes system firewall policy
Worm:Win32/Abfewsm.A modifies the following registry entry, which prevents the system firewall from working:
 
Modifies value: "Epoch"
From data: "6A, 60, 00, 00"
To data: "6B, 60, 00, 00"
In subkey: HKLM\SYSTEM\ControlSet001\Services\SharedAccess\Epoch
 
It also modifies the firewall policy so that its copy is tagged as an authorized application and able to pass through the firewall:
 
Adds value: "<system folder>\KHATRA.exe"
With data: "<system folder>\KHATRA.exe:*:Enabled:System"
To subkey: HKLM\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
 
Modifies system settings
Worm:Win32/Abfewsm.A disables the option in Windows Explorer to show all files:
 
Adds value: "CheckedValue"
With data: "0"
To subkey: HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Folder\Hidden\SHOWALL
 
It also enables certain files to be tagged as 'hidden':
 
Adds value: "Hidden"
With data: "0"
To subkey: HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
 
Worm:Win32/Abfewsm.A also disables the Control Panel and the registry editor tools by modifying the following registry entries:
 
Modifies value: "NoControlPanel"
With data: "1"
To subkey: HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
 
Modifies value: "DisableRegistryTools"
With data: "1"
To subkey: HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\System
 
Modifies Internet Explorer settings
Worm:Win32/Abfewsm.A changes the window title for Internet Explorer to "Internet Exploiter".
 
Analysis by Jaime Wong

Symptoms

System changes
The following system changes may indicate the presence of this malware:
  • The presence of the following files in the Windows folder:
    CyberWar.cab
    fh_antivirussetup6534.cab
    kavSetupEng3857.cab
    mario675.cab
    New WinRAR archive.cab
    New WinRAR ZIP archive.cab
    New WinZip File.cab
    new-screamsaver.com.cab
    supermodels.cab
    Youtube.cab
  • The presence of the following files:
    %windir%\KHATARNAKH.exe
    %windir%\Xplorer.exe
    %systemroot%\KHATRA.exe
    %windir%\system\gHost.exe
    <system folder>\KHATRA.exe

    %AppData%\Microsoft\CD Burning\Administrator.exe
    %AppData%\Microsoft\CD Burning\KHATRA.exe
    %AppData%\Microsoft\CD Burning\New Folder(3).exe

    %windir%\K.Backup\C_Drive_Documents and Settings_Administrator_Start Menu_Programs_Startup_desktop.ini.FUCKED
    %windir%\K.Backup\C_Drive_Documents and Settings_All Users_Start Menu_Programs_Startup_desktop.ini.FUCKED
    %windir%\K.Backup\C_Drive_Documents and Settings_All Users_Start Menu_Programs_Startup_whoami.lnk.FUCKED
  • The presence of the following registry entries:
    Added value: "PHIME2002A"
    With data: "<system folder>\KHATRA.exe"
    To subkey: HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    Added value: "PHIME2002ASync"
    With data: "%windir%\Xplorer.exe"
    To subkey: HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    Added value: "load"
    With data: "<system folder>\KHATRA.exe"
    To subkey: HKCU\Software\Microsoft\Windows NT\CurrentVersion\Windows%windir%
  • The presence of the following registry key:
    HKLM\SOFTWARE\KHATRA
  • The window title for Internet Explorer is changed to "Internet Exploiter"

Prevention


Alert level: Severe
First detected by definition: 1.57.181.0
Latest detected by definition: 1.173.2181.0 and higher
First detected on: Apr 23, 2009
This entry was first published on: Oct 09, 2009
This entry was updated on: Apr 17, 2011

This threat is also detected as:
  • Win32/SillyAutorun.AJH (CA)
  • Trojan-Dropper.Win32.Autoit.y (Kaspersky)
  • AutoIt.BT (Norman)
  • W32/Autoit-EA (Sophos)
  • Trojan.DR.Autoit.WG (VirusBuster)
  • Win32/AutoRun.Autoit.AH (ESET)
  • W32/Autorun.worm.h (McAfee)
  • W32/Sohanat.IW (Panda)