Trojan.Win32.Scar.hslu_7ce13b49bd

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 Trojan's file once a user opens a drive's folder in Windows Explorer.

Process activity

The Trojan creates the following process(es):

f3ahvoas.exe:384
%original file name%.exe:132
%original file name%.exe:1060
reg.exe:212
reg.exe:888
reg.exe:500
reg.exe:1008
reg.exe:496
reg.exe:1416
iexplore.exe:468
faultrep.exe:220

The Trojan injects its code into the following process(es):No processes have been created.

File activity

The process f3ahvoas.exe:384 makes changes in the file system.

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

%System%\_Setup.bat (580 bytes)

The process %original file name%.exe:132 makes changes in the file system.

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

%System%\c_l4946.nls (1554 bytes)
%System%\faultrep.exe (70 bytes)
%System%\_Setup.bat (580 bytes)

The process %original file name%.exe:1060 makes changes in the file system.

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

%System%\uret463.exe (673 bytes)
%System%\drivers\klif.sys (3 bytes)
%System%\lhgjyit0.dll (127 bytes)

The Trojan deletes the following file(s):

%System%\drivers\klif.sys (0 bytes)

The process faultrep.exe:220 makes changes in the file system.

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

%System%\fmifs.nls (464 bytes)
%System%\f3ahvoas.exe (601 bytes)
%System%\filemgmt.nls (4 bytes)
%System%\_Setup.bat (580 bytes)

Registry activity

The process f3ahvoas.exe:384 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "0E A7 3C 07 AB D5 00 A2 C4 72 E1 D6 65 F6 28 4A"

The process %original file name%.exe:132 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "30 A9 10 66 37 24 98 C4 77 16 53 D3 9D 98 F1 7B"

The process %original file name%.exe:1060 makes changes in the system registry.

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

[HKLM\System\CurrentControlSet\Services\KAVsys]
"Type" = "1"
"ImagePath" = "\??\%System%\drivers\klif.sys"
"ErrorControl" = "1"

The following driver will be automatically launched by the NT Native code (IoInitSystem method):

[HKLM\System\CurrentControlSet\Services\KAVsys]
"Start" = "1"

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

[HKCU\Software\Microsoft\Windows\CurrentVersion\Run]
"dorfgwe" = "%System%\uret463.exe"

The Trojan deletes the following registry key(s):

[HKLM\System\CurrentControlSet\Services\KAVsys]

The process reg.exe:212 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "E7 08 E9 10 AF 9A 0B 4F E4 A8 2B 54 AD 00 2A 51"

[HKLM\SOFTWARE\Microsoft\Active Setup\Installed Components\{L7TJ3YO2-Z299-96B6-J553-1X86390KS5G5}]
"StubPath" = "%System%\cmd.exe /c %System%\faultrep.exe /i"

The process reg.exe:888 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "91 AB 44 8A 0C B3 35 17 16 41 BD DB 9E 4D 07 96"

The process reg.exe:500 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "18 C5 A6 0D A9 5C 16 4A 40 83 39 25 1F 2C 9B 60"

[HKLM\SOFTWARE\Microsoft\Active Setup\Installed Components\{L7TJ3YO2-Z299-96B6-J553-1X86390KS5G5}]
"StubPath" = "%System%\cmd.exe /c %System%\faultrep.exe /i"

The process reg.exe:1008 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "A5 4C 99 73 58 97 7A 96 22 34 F7 2F B4 19 A0 29"

The process reg.exe:496 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "8D 4A 91 F1 D7 BE F2 1C 0A E1 0F 1D 11 D8 B9 15"

[HKLM\SOFTWARE\Microsoft\Active Setup\Installed Components\{L7TJ3YO2-Z299-96B6-J553-1X86390KS5G5}]
"StubPath" = "%System%\cmd.exe /c %System%\faultrep.exe /i"

The process reg.exe:1416 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "AB FC 51 75 47 B3 4C ED A9 BF 1E EB 08 9D 1A 23"

The process iexplore.exe:468 makes changes in the system registry.

The Trojan 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"

[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"

"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\Shell Folders]
"Cache" = "%Documents and Settings%\%current user%\Local Settings\Temporary Internet Files"

[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 1B 00 00 00 01 00 00 00 00 00 00 00"

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "9E C9 92 D8 82 C3 FC A2 0A 2E BB 25 36 60 7A DE"

[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"

[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 Trojan 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 Trojan 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 Trojan 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 Trojan deletes the following value(s) in system registry:

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

The process faultrep.exe:220 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "69 E4 D4 7A 1C EA F8 D7 CE 7C 68 68 ED 93 F3 84"

Network activity (URLs)

URL	IP
hxxp://qwer5.homelinux.com/config2.asp?id=A8A67A25	184.72.54.44

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 Trojan'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):

   f3ahvoas.exe:384
   %original file name%.exe:132
   %original file name%.exe:1060
   reg.exe:212
   reg.exe:888
   reg.exe:500
   reg.exe:1008
   reg.exe:496
   reg.exe:1416
   iexplore.exe:468
   faultrep.exe:220

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

   %System%\_Setup.bat (580 bytes)
   %System%\c_l4946.nls (1554 bytes)
   %System%\faultrep.exe (70 bytes)
   %System%\uret463.exe (673 bytes)
   %System%\drivers\klif.sys (3 bytes)
   %System%\lhgjyit0.dll (127 bytes)
   %System%\fmifs.nls (464 bytes)
   %System%\f3ahvoas.exe (601 bytes)
   %System%\filemgmt.nls (4 bytes)
   

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

   [HKCU\Software\Microsoft\Windows\CurrentVersion\Run]
   "dorfgwe" = "%System%\uret463.exe"

5. Clean the Temporary Internet Files folder, which may contain infected files (How to clean Temporary Internet Files folder).
   
6. Find and delete all copies of the worm's file together with "autorun.inf" scripts on removable drives.
   
7. 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