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Backdoor.Win32.Farfli_aa998d8835


Gen:Variant.Zusy.31009 (B) (Emsisoft), MSIL:Bladabindi-CI [Trj] (Avast), Backdoor.Win32.Farfli.FD, Backdoor.Win32.Xtrat.FD, Trojan.Win32.IEDummy.FD, GenericAutorunWorm.YR, GenericInjector.YR (Lavasoft MAS)Behaviour: Trojan, Backdoor, Worm, WormAutorun

The description has been automatically generated by Lavasoft Malware Analysis System and it may contain incomplete or inaccurate information.

Summary

MD5: aa998d883598fb9dd100723fa868f0d3

SHA1: e24683fffd8b2f26c8b59a7d070f5915382276c6

SHA256: acc23611f3f9e3e57f6981e87b17c99061ebfa016c18278de4a2a3904c7534fe

SSDeep: 24576:aN7wSzrgLcLJFYu8gK F8WnFiSLEel0UCEBAMm:aN7worgLcLJmQK6RFiSLECCEBA

Size: 1011712 bytes

File type: EXE

Platform: WIN32

Entropy: Not Packed

PEID: MicrosoftVisualC, NETexecutable, UPolyXv05_v6

Company: no certificate found

Created at: 2014-02-17 23:34:15

Analyzed on: WindowsXP SP3 32-bit

Summary: Backdoor. Malware that enables a remote control of victim's machine.

Dynamic Analysis

Payload

Behaviour Description
WormAutorunA worm can spread via removable drives. It writes its executable and creates "autorun.inf" scripts on all removable drives. The autorun script will execute the Backdoor's file once a user opens a drive's folder in Windows Explorer.


Process activity

The Backdoor creates the following process(es):

Name.exe:616
dllhost.exe:1316
%original file name%.exe:1808

The Backdoor injects its code into the following process(es):

iexplore.exe:1088

File activity

The process Name.exe:616 makes changes in the file system.


The Backdoor creates and/or writes to the following file(s):

%Documents and Settings%\%current user%\Start Menu\Programs\Startup\HKCU.exe (7385 bytes)

The process iexplore.exe:1088 makes changes in the file system.


The Backdoor creates and/or writes to the following file(s):

%WinDir%\InstallDir\Server.exe (5 bytes)
%Documents and Settings%\%current user%\Application Data\Microsoft\Windows\szpCgR.dat (314 bytes)

The process dllhost.exe:1316 makes changes in the file system.


The Backdoor deletes the following file(s):

%Documents and Settings%\%current user%\Local Settings\Temp\x.html (0 bytes)

The process %original file name%.exe:1808 makes changes in the file system.


The Backdoor creates and/or writes to the following file(s):

%Documents and Settings%\%current user%\Application Data\Name.exe (7385 bytes)

Registry activity

The process Name.exe:616 makes changes in the system registry.


The Backdoor creates and/or sets the following values in system registry:

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "B3 3A C3 35 FF 17 1C 9E 47 C3 E3 2F 09 8D FF 1E"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders]
"Startup" = "%Documents and Settings%\%current user%\Start Menu\Programs\Startup"
"AppData" = "%Documents and Settings%\%current user%\Application Data"
"Cache" = "%Documents and Settings%\%current user%\Local Settings\Temporary Internet Files"

To automatically run itself each time Windows is booted, the Backdoor adds the following link to its file to the system registry autorun key:

[HKCU\Software\Microsoft\Windows\CurrentVersion\Run]
"HKCU" = "%Documents and Settings%\%current user%\Application Data\Name.exe"

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
"HKLM" = "%Documents and Settings%\%current user%\Application Data\Name.exe"

The process iexplore.exe:1088 makes changes in the system registry.


The Backdoor creates and/or sets the following values in system registry:

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Cache\Paths]
"Directory" = "%Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5"

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Cache\Paths\path4]
"CacheLimit" = "65452"
"CachePath" = "%Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5\Cache4"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Connections]
"SavedLegacySettings" = "3C 00 00 00 14 00 00 00 01 00 00 00 00 00 00 00"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders]
"AppData" = "%Documents and Settings%\%current user%\Application Data"

[HKCU\Software\szpCgR]
"ServerStarted" = "20/02/2014 01:59:23"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\MountPoints2\{c155cd73-744b-11e2-8294-806d6172696f}]
"BaseClass" = "Drive"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders]
"Cookies" = "%Documents and Settings%\%current user%\Cookies"

[HKLM\SOFTWARE\Microsoft\DirectDraw\MostRecentApplication]
"ID" = "1208111653"

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Cache\Paths\path2]
"CachePath" = "%Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5\Cache2"

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders]
"Common AppData" = "%Documents and Settings%\All Users\Application Data"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\MountPoints2\{c155cd75-744b-11e2-8294-806d6172696f}]
"BaseClass" = "Drive"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders]
"Cache" = "%Documents and Settings%\%current user%\Local Settings\Temporary Internet Files"

[HKCU\Software\szpCgR]
"ServerName" = "%WinDir%\InstallDir\Server.exe"

[HKLM\SOFTWARE\Microsoft\DirectDraw\MostRecentApplication]
"Name" = "iexplore.exe"

[HKLM\System\CurrentControlSet\Hardware Profiles\0001\Software\Microsoft\windows\CurrentVersion\Internet Settings]
"ProxyEnable" = "0"

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Cache\Paths\path1]
"CacheLimit" = "65452"

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Cache\Paths\path2]
"CacheLimit" = "65452"

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "C3 00 8B DA 71 A2 82 B1 8C CE F9 EE 21 EE FF 97"

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Cache\Paths\path1]
"CachePath" = "%Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5\Cache1"

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Cache\Paths\path3]
"CacheLimit" = "65452"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings]
"MigrateProxy" = "1"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\MountPoints2\{c155cd72-744b-11e2-8294-806d6172696f}]
"BaseClass" = "Drive"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\MountPoints2\{b98117e8-75ca-11e2-81b2-000c293708fb}]
"BaseClass" = "Drive"

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Cache\Paths\path3]
"CachePath" = "%Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5\Cache3"

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Cache\Paths]
"Paths" = "4"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders]
"History" = "%Documents and Settings%\%current user%\Local Settings\History"

[HKLM\SOFTWARE\Microsoft\Active Setup\Installed Components\{311FTJOI-1KUL-G4N6-782W-JYP4573BHE7O}]
"StubPath" = "%WinDir%\InstallDir\Server.exe restart"

The Backdoor modifies IE settings for security zones to map all local web-nodes with no dots which do not refer to any zone to the Intranet Zone:

[HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings\ZoneMap]
"UNCAsIntranet" = "1"

To automatically run itself each time Windows is booted, the Backdoor adds the following link to its file to the system registry autorun key:

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
"HKLM" = "%WinDir%\InstallDir\Server.exe"

The Backdoor modifies IE settings for security zones to map all urls to the Intranet Zone:

[HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings\ZoneMap]
"IntranetName" = "1"

The Backdoor modifies IE settings for security zones to map all web-nodes that bypassing proxy to the Intranet Zone:

"ProxyBypass" = "1"

To automatically run itself each time Windows is booted, the Backdoor adds the following link to its file to the system registry autorun key:

[HKCU\Software\Microsoft\Windows\CurrentVersion\Run]
"HKCU" = "%WinDir%\InstallDir\Server.exe"

Proxy settings are disabled:

[HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings]
"ProxyEnable" = "0"

The Backdoor deletes the following value(s) in system registry:

[HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings]
"AutoConfigURL"
"ProxyServer"
"ProxyOverride"

The process dllhost.exe:1316 makes changes in the system registry.


The Backdoor creates and/or sets the following values in system registry:

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "90 E6 F3 37 18 69 30 4F 10 86 89 4C 6D B9 75 57"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\MountPoints2\{c155cd73-744b-11e2-8294-806d6172696f}]
"BaseClass" = "Drive"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\MountPoints2\{c155cd72-744b-11e2-8294-806d6172696f}]
"BaseClass" = "Drive"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\MountPoints2\{b98117e8-75ca-11e2-81b2-000c293708fb}]
"BaseClass" = "Drive"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders]
"AppData" = "%Documents and Settings%\%current user%\Application Data"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\MountPoints2\{c155cd75-744b-11e2-8294-806d6172696f}]
"BaseClass" = "Drive"

[HKCU\Software\XtremeRAT]
"Mutex" = "szpCgR"

The process %original file name%.exe:1808 makes changes in the system registry.


The Backdoor creates and/or sets the following values in system registry:

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "49 2B 55 20 A8 2B 12 81 5A BD 0E 1A 20 9B E5 6B"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\MountPoints2\{c155cd73-744b-11e2-8294-806d6172696f}]
"BaseClass" = "Drive"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders]
"Cookies" = "%Documents and Settings%\%current user%\Cookies"

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders]
"Common Documents" = "%Documents and Settings%\All Users\Documents"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders]
"Desktop" = "%Documents and Settings%\%current user%\Desktop"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\MountPoints2\{c155cd72-744b-11e2-8294-806d6172696f}]
"BaseClass" = "Drive"

[HKCU\Software\Microsoft\Windows\ShellNoRoam\MUICache\%Documents and Settings%\%current user%\Application Data]
"Name.exe" = "Firefox"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\MountPoints2\{b98117e8-75ca-11e2-81b2-000c293708fb}]
"BaseClass" = "Drive"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders]
"AppData" = "%Documents and Settings%\%current user%\Application Data"

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders]
"Common Desktop" = "%Documents and Settings%\All Users\Desktop"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\MountPoints2\{c155cd75-744b-11e2-8294-806d6172696f}]
"BaseClass" = "Drive"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders]
"Cache" = "%Documents and Settings%\%current user%\Local Settings\Temporary Internet Files"

"Personal" = "%Documents and Settings%\%current user%\My Documents"

The Backdoor modifies IE settings for security zones to map all local web-nodes with no dots which do not refer to any zone to the Intranet Zone:

[HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings\ZoneMap]
"UNCAsIntranet" = "1"

The Backdoor modifies IE settings for security zones to map all urls to the Intranet Zone:

"IntranetName" = "1"

The Backdoor modifies IE settings for security zones to map all web-nodes that bypassing proxy to the Intranet Zone:

"ProxyBypass" = "1"

Network activity (URLs)

No activity has been detected.

HOSTS file anomalies

No changes have been detected.

Rootkit activity

No anomalies have been detected.

Propagation

A worm can spread via removable drives. It writes its executable and creates "autorun.inf" scripts on all removable drives. The autorun script will execute the Backdoor's file once a user opens a drive's folder in Windows Explorer.

Removals

Remove it with Ad-Aware

  1. Click (here) to download and install Ad-Aware Free Antivirus.
  2. Update the definition files.
  3. Run a full scan of your computer.

Manual removal*

  1. Terminate malicious process(es) (How to End a Process With the Task Manager):

    Name.exe:616
    dllhost.exe:1316
    %original file name%.exe:1808

  2. Delete the original Backdoor file.
  3. Delete or disinfect the following files created/modified by the Backdoor:

    %Documents and Settings%\%current user%\Start Menu\Programs\Startup\HKCU.exe (7385 bytes)
    %WinDir%\InstallDir\Server.exe (5 bytes)
    %Documents and Settings%\%current user%\Application Data\Microsoft\Windows\szpCgR.dat (314 bytes)
    %Documents and Settings%\%current user%\Application Data\Name.exe (7385 bytes)

  4. Delete the following value(s) in the autorun key (How to Work with System Registry):

    [HKCU\Software\Microsoft\Windows\CurrentVersion\Run]
    "HKCU" = "%Documents and Settings%\%current user%\Application Data\Name.exe"

    [HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
    "HKLM" = "%Documents and Settings%\%current user%\Application Data\Name.exe"

    [HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
    "HKLM" = "%WinDir%\InstallDir\Server.exe"

    [HKCU\Software\Microsoft\Windows\CurrentVersion\Run]
    "HKCU" = "%WinDir%\InstallDir\Server.exe"

  5. Find and delete all copies of the worm's file together with "autorun.inf" scripts on removable drives.
  6. Reboot the computer.
*Manual removal may cause unexpected system behaviour and should be performed at your own risk.

Static Analysis

Network Activity

Map

Strings from Dumps