Backdoor.Win32.Farfli_2db2f7d485

by malwarelabrobot on August 23rd, 2013 in Malware Descriptions.

HEUR:Trojan.Win32.Generic (Kaspersky), Trojan.Win32.Generic!BT (VIPRE), Trojan.Win32.Llac!IK (Emsisoft), 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
Technical Details
Removal Recommendations

MD5: 2db2f7d48504f5ad9c731e00b3f2f74f
SHA1: 65ae83b102f6c19e7d649be5641254a44253d748
SHA256: d44724d26a99ea92506a305cd76afed688d6cf36dc3ce47c29b454b6e46bbc61
SSDeep: 3072:v1kA55Gjdh2pHj6sHGgx4IboyeiVBcY5rWpy6W7o6 Nq6LTBYKRD68wb:4jdhmj1HGgGC1V/cCrWrXVldvD68w
Size: 153088 bytes
File type: EXE
Platform: WIN32
Entropy: Packed
PEID: MicrosoftVisualC, NETexecutable, UPolyXv05_v6
Company: StarApp
Created at: 2013-06-08 18:50:14


Summary:

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

Payload

Behaviour Description
WormAutorun 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.


Process activity

The Backdoor creates the following process(es):

2db2f7d48504f5ad9c731e00b3f2f74f.exe:1844

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

iexplore.exe:1812

File activity

The process 2db2f7d48504f5ad9c731e00b3f2f74f.exe:1844 makes changes in a file system.
The Backdoor creates and/or writes to the following file(s):

%Documents and Settings%\%current user%\Application Data\Winlogon\winlogon.exe (673 bytes)

The process iexplore.exe:1812 makes changes in a file system.
The Backdoor creates and/or writes to the following file(s):

%Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5\desktop.ini (67 bytes)
%Documents and Settings%\%current user%\Application Data\InstallDir\Server.exe (3073 bytes)
%Documents and Settings%\%current user%\Application Data\Microsoft\Windows\--((Mutex))--.dat (314 bytes)

Registry activity

The process 2db2f7d48504f5ad9c731e00b3f2f74f.exe:1844 makes changes in a system registry.
The Backdoor creates and/or sets the following values in system registry:

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "C1 A7 CC 09 10 50 E4 8E 3A FE 42 EB CF A0 50 73"

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

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders]
"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\c:]
"2db2f7d48504f5ad9c731e00b3f2f74f.exe" = "%Documents and Settings%\%current user%\Application Data\Winlogon\winlogon.exe"

The process iexplore.exe:1812 makes changes in a 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"

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Cache\Paths\path4]
"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 17 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\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"

[HKCU\Software\--((Mutex))--]
"ServerStarted" = "22/08/2013 12:53:14"

[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"

[HKLM\SOFTWARE\Microsoft\Active Setup\Installed Components\{5460C4DF-B266-909E-CB58-E32B79832EB2}]
"StubPath" = "%Documents and Settings%\%current user%\Application Data\InstallDir\Server.exe restart"

[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" = "F5 89 9A 26 43 D3 45 4B 48 69 D7 8A C0 FC 15 21"

[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"

[HKCU\Software\--((Mutex))--]
"ServerName" = "%Documents and Settings%\%current user%\Application Data\InstallDir\Server.exe"

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" = "%Documents and Settings%\%current user%\Application Data\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:

[HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings\ZoneMap]
"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" = "%Documents and Settings%\%current user%\Application Data\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"

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

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

Network activity (URLs)

No activity has 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.


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):

    2db2f7d48504f5ad9c731e00b3f2f74f.exe:1844

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

    %Documents and Settings%\%current user%\Application Data\Winlogon\winlogon.exe (673 bytes)
    %Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5\desktop.ini (67 bytes)
    %Documents and Settings%\%current user%\Application Data\InstallDir\Server.exe (3073 bytes)
    %Documents and Settings%\%current user%\Application Data\Microsoft\Windows\--((Mutex))--.dat (314 bytes)

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

    [HKCU\Software\Microsoft\Windows\CurrentVersion\Run\c:]
    "2db2f7d48504f5ad9c731e00b3f2f74f.exe" = "%Documents and Settings%\%current user%\Application Data\Winlogon\winlogon.exe"

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

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