Backdoor.Win32.Xtrat_c5ab5cf6a3

by malwarelabrobot on December 10th, 2013 in Malware Descriptions.

UDS:DangerousObject.Multi.Generic (Kaspersky), 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: c5ab5cf6a382a9985c614d72da5fb385
SHA1: 9ddb12a49e4ebbec59bf9072405be3d9cc6b6f2c
SHA256: 7ce1cc8daa8acb77337045ff5e6dd31421406334ff468a1e0f132e161c2c889d
SSDeep: 6144:whVCorGwPEgTcYtEKhVx0GoOILNnvWQrjgf:wzCYfwmT0ZJOWgf
Size: 251904 bytes
File type: EXE
Platform: WIN32
Entropy: Packed
PEID: MicrosoftVisualC, NETexecutable, UPolyXv05_v6
Company: F
Created at: 2013-12-06 03:13:07


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):

%original file name%.exe:764
wscript.exe:480
uyttttt.exe:988

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

iexplore.exe:1104

File activity

The process %original file name%.exe:764 makes changes in the file system.
The Backdoor creates and/or writes to the following file(s):

%Documents and Settings%\%current user%\Local Settings\Temp\uyttttt.exe (1281 bytes)

The process wscript.exe:480 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 iexplore.exe:1104 makes changes in the file system.
The Backdoor creates and/or writes to the following file(s):

%System%\InstallDir\Server.exe (673 bytes)
%Documents and Settings%\%current user%\Application Data\Microsoft\Windows\oKSNlVhdlQRxtq2c.dat (314 bytes)
%Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5\desktop.ini (67 bytes)

The process uyttttt.exe:988 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\trreee.exe (1281 bytes)

Registry activity

The process %original file name%.exe:764 makes changes in the system registry.
The Backdoor creates and/or sets the following values in system registry:

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "3B CE C7 F4 B4 39 FB BB 34 D4 10 C4 3D BE AA AD"

[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\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"

[HKCU\Software\Microsoft\Windows\ShellNoRoam\MUICache\%Documents and Settings%\%current user%\Local Settings\Temp]
"uyttttt.exe" = "Firefox"

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"

The process wscript.exe:480 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 9E 6B F5 E8 D4 F2 3A D1 E7 ED 11 D6 94 A7 C0"

[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" = "oKSNlVhdlQRxtq2c"

The process iexplore.exe:1104 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 16 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"

[HKLM\SOFTWARE\Microsoft\Active Setup\Installed Components\{Q3BLMQ4W-ATG1-OGFS-O8BM-36U50Q567H44}]
"StubPath" = "%System%\InstallDir\Server.exe restart"

[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\oKSNlVhdlQRxtq2c]
"ServerStarted" = "09/12/2013 04:22:05"

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

[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" = "B2 EF 1D EC 1C 40 90 64 3F 99 FD 89 80 24 30 A9"

[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"

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" = "%System%\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" = "%System%\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 uyttttt.exe:988 makes changes in the system registry.
The Backdoor creates and/or sets the following values in system registry:

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "3D BF 1C C3 92 6C AB 6E A3 89 C7 59 FC 2B 32 9B"

[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:

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
"trreee" = "%Documents and Settings%\%current user%\Local Settings\Temp\uyttttt.exe"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Run]
"trreee" = "%Documents and Settings%\%current user%\Local Settings\Temp\uyttttt.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.


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:764
    wscript.exe:480
    uyttttt.exe:988

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

    %Documents and Settings%\%current user%\Local Settings\Temp\uyttttt.exe (1281 bytes)
    %System%\InstallDir\Server.exe (673 bytes)
    %Documents and Settings%\%current user%\Application Data\Microsoft\Windows\oKSNlVhdlQRxtq2c.dat (314 bytes)
    %Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5\desktop.ini (67 bytes)
    %Documents and Settings%\%current user%\Start Menu\Programs\Startup\trreee.exe (1281 bytes)

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

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

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

    [HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
    "trreee" = "%Documents and Settings%\%current user%\Local Settings\Temp\uyttttt.exe"

    [HKCU\Software\Microsoft\Windows\CurrentVersion\Run]
    "trreee" = "%Documents and Settings%\%current user%\Local Settings\Temp\uyttttt.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.