Backdoor.Win32.Farfli_78b6015fc9

Dynamic Analysis

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):

%original file name%.exe:524
%original file name%.exe:1812
notepad.exe:1596
notepad.exe:1808
System.exe:572
System.exe:1492
System.exe:448
System.exe:652

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

notepad.exe:920

File activity

The process %original file name%.exe:524 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\system.pif (673 bytes)
%Documents and Settings%\All Users\Start Menu\Programs\Startup\system.pif (673 bytes)
%WinDir%\InstallDir\help.exe (673 bytes)

The process %original file name%.exe:1812 makes changes in the file system.

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

%System%\Logs\System.exe (673 bytes)
%Documents and Settings%\%current user%\Application Data\Microsoft\Windows\System.cfg (2 bytes)

The process notepad.exe:1808 makes changes in the 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\OPQNSD2J\1234567890[1].functions (84793 bytes)
%Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5\OPQNSD2J\desktop.ini (67 bytes)
%Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5\desktop.ini (67 bytes)
%Documents and Settings%\%current user%\Application Data\Microsoft\Windows\System.dat (282 bytes)
%Documents and Settings%\%current user%\Application Data\Microsoft\Windows\System.xtr (77262 bytes)

The process System.exe:572 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\system.pif (673 bytes)
%Documents and Settings%\All Users\Start Menu\Programs\Startup\system.pif (673 bytes)
%WinDir%\InstallDir\help.exe (673 bytes)

The process System.exe:448 makes changes in the file system.

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

%Documents and Settings%\%current user%\Application Data\Microsoft\Windows\System.cfg (2 bytes)

The Backdoor deletes the following file(s):

%Documents and Settings%\%current user%\Application Data\Microsoft\Windows\System.cfg (0 bytes)

The process System.exe:652 makes changes in the file system.

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

%Documents and Settings%\%current user%\Application Data\Microsoft\Windows\System.cfg (2 bytes)

The Backdoor deletes the following file(s):

%Documents and Settings%\%current user%\Application Data\Microsoft\Windows\System.cfg (0 bytes)

Registry activity

The process %original file name%.exe:524 makes changes in the system registry.

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

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

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]
"help" = "%WinDir%\InstallDir\help.exe"

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

The process %original file name%.exe:1812 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "08 DC 5C 60 C4 BC D3 CC B7 F3 9E 82 24 DB 39 7B"

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

[HKCU\Software\System]
"ServerStarted" = "11/20/2013 12:38:12 PM"

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

[HKLM\SOFTWARE\Microsoft\Active Setup\Installed Components\{M0PMYUT4-K66U-UKQK-8678-02LXIX1G47C3}]
"StubPath" = "%System%\Logs\System.exe restart"

[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\System]
"InstalledServer" = "%System%\Logs\System.exe"

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]
"System" = "%System%\Logs\System.exe"

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
"System" = "%System%\Logs\System.exe"

The process notepad.exe:920 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "29 A2 83 DC 78 C3 FA E9 EF B3 73 64 68 FE 37 3D"

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

[HKCU\Software\System]
"NewId" = "^^العكيد^^"

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

[HKLM\SOFTWARE\Microsoft\Active Setup\Installed Components\{M0PMYUT4-K66U-UKQK-8678-02LXIX1G47C3}]
"StubPath" = "%System%\Logs\System.exe restart"

[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\System]
"NewGroup" = "Servers"

"FirstExecution" = "20/11/2013 12:38:37"

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]
"System" = "%System%\Logs\System.exe"

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
"System" = "%System%\Logs\System.exe"

The Backdoor deletes the following registry key(s):

[HKCU\Software\652]

The process notepad.exe:1596 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "FA A0 0B EF 57 4C 5A 11 56 B9 FF D7 34 59 B5 97"

The Backdoor deletes the following registry key(s):

[HKCU\Software\448]

The process notepad.exe:1808 makes changes in the system registry.

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

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

[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"

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

[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 Documents" = "%Documents and Settings%\All Users\Documents"

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

[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\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"

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

[HKCU\Software\Microsoft\Windows\ShellNoRoam\MUICache\%System%\Logs]
"System.exe" = "sdbhsrtyjm"

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

"Desktop" = "%Documents and Settings%\%current user%\Desktop"

[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"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Connections]
"SavedLegacySettings" = "3C 00 00 00 16 00 00 00 01 00 00 00 00 00 00 00"

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "2F 8C D2 D9 A0 CF BE F9 20 89 BA 90 69 BD 5E 70"

[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\Shell Folders]
"History" = "%Documents and Settings%\%current user%\Local Settings\History"

[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"

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 web-nodes that bypassing proxy to the Intranet Zone:

"ProxyBypass" = "1"

Proxy settings are disabled:

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

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 deletes the following value(s) in system registry:

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

The process System.exe:572 makes changes in the system registry.

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

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

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]
"help" = "%WinDir%\InstallDir\help.exe"

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

The process System.exe:1492 makes changes in the system registry.

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

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

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]
"help" = "%WinDir%\InstallDir\help.exe"

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

The process System.exe:448 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "44 51 D9 E6 CA 8D D3 54 78 E6 BA 0B A9 D2 92 5C"

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

[HKCU\Software\448]
"Mutex" = "System"

[HKCU\Software\System]
"ServerStarted" = "11/20/2013 12:38:32 PM"

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

[HKLM\SOFTWARE\Microsoft\Active Setup\Installed Components\{M0PMYUT4-K66U-UKQK-8678-02LXIX1G47C3}]
"StubPath" = "%System%\Logs\System.exe restart"

[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\System]
"InstalledServer" = "%System%\Logs\System.exe"

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]
"System" = "%System%\Logs\System.exe"

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
"System" = "%System%\Logs\System.exe"

The process System.exe:652 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "D9 FE 29 E2 6B 53 AC 7D 5F 0A 03 D6 13 8D 59 AD"

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

[HKCU\Software\System]
"ServerStarted" = "11/20/2013 12:38:34 PM"

[HKCU\Software\652]
"Mutex" = "System"

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

[HKLM\SOFTWARE\Microsoft\Active Setup\Installed Components\{M0PMYUT4-K66U-UKQK-8678-02LXIX1G47C3}]
"StubPath" = "%System%\Logs\System.exe restart"

[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\System]
"InstalledServer" = "%System%\Logs\System.exe"

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]
"System" = "%System%\Logs\System.exe"

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
"System" = "%System%\Logs\System.exe"

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):

   %original file name%.exe:524
   %original file name%.exe:1812
   notepad.exe:1596
   notepad.exe:1808
   System.exe:572
   System.exe:1492
   System.exe:448
   System.exe:652

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\system.pif (673 bytes)
   %Documents and Settings%\All Users\Start Menu\Programs\Startup\system.pif (673 bytes)
   %WinDir%\InstallDir\help.exe (673 bytes)
   %System%\Logs\System.exe (673 bytes)
   %Documents and Settings%\%current user%\Application Data\Microsoft\Windows\System.cfg (2 bytes)
   %Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5\OPQNSD2J\1234567890[1].functions (84793 bytes)
   %Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5\OPQNSD2J\desktop.ini (67 bytes)
   %Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5\desktop.ini (67 bytes)
   %Documents and Settings%\%current user%\Application Data\Microsoft\Windows\System.dat (282 bytes)
   %Documents and Settings%\%current user%\Application Data\Microsoft\Windows\System.xtr (77262 bytes)
   

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

   [HKCU\Software\Microsoft\Windows\CurrentVersion\Run]
   "help" = "%WinDir%\InstallDir\help.exe"
   
   [HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
   "help" = "%WinDir%\InstallDir\help.exe"
   
   [HKCU\Software\Microsoft\Windows\CurrentVersion\Run]
   "System" = "%System%\Logs\System.exe"
   
   [HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
   "System" = "%System%\Logs\System.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