Backdoor.Win32.Xtrat_0c892510fa

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):

vbc.exe:2020
%original file name%.exe:2024

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

notepad.exe:436

Mutexes

The following mutexes were created/opened:No objects were found.

File activity

The process notepad.exe:436 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\InstallDir\updater.exe (7547 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\Zow47bTpx.dat (322 bytes)

Registry activity

The process vbc.exe:2020 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "7A 4E 9B 95 35 3E D8 6C 09 D4 79 2E 5C 38 44 D3"

[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" = "Zow47bTpx"

The process %original file name%.exe:2024 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "1A F0 D1 B6 DB 5E 16 F2 FB 29 F8 FF AD DB 3C E0"

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

The process notepad.exe:436 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 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" = "1208111751"

[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"

[HKLM\SOFTWARE\Microsoft\DirectDraw\MostRecentApplication]
"Name" = "notepad.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\Active Setup\Installed Components\{8Q5SI75H-5L0W-2LSN-I048-17Y15Q411653}]
"StubPath" = "C:\DOCUME~1\"%CurrentUserName%"\LOCALS~1\Temp\InstallDir\updater.exe restart"

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "50 39 5F 21 F2 94 5C 06 D9 1C 5B 17 75 61 CE D2"

[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\Zow47bTpx]
"ServerStarted" = "22/06/2014 22:04:20"

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" = "C:\DOCUME~1\"%CurrentUserName%"\LOCALS~1\Temp\InstallDir\updater.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 the 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" = "C:\DOCUME~1\"%CurrentUserName%"\LOCALS~1\Temp\InstallDir\updater.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"

Dropped PE files

MD5	File path
67f5238229333c061092f5a32e8c2ee1	c:\Documents and Settings\"%CurrentUserName%"\Local Settings\Temp\InstallDir\updater.exe

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):

   vbc.exe:2020
   %original file name%.exe:2024
   

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\InstallDir\updater.exe (7547 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\Zow47bTpx.dat (322 bytes)

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

   [HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
   "HKLM" = "C:\DOCUME~1\"%CurrentUserName%"\LOCALS~1\Temp\InstallDir\updater.exe"
   
   [HKCU\Software\Microsoft\Windows\CurrentVersion\Run]
   "HKCU" = "C:\DOCUME~1\"%CurrentUserName%"\LOCALS~1\Temp\InstallDir\updater.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

VersionInfo

Company Name:
Product Name:
Product Version: 0.0.0.0
Legal Copyright:
Legal Trademarks:
Original Filename: Chrome.exe
Internal Name: Chrome.exe
File Version: 0.0.0.0
File Description:
Comments:
Language: English (United States)

Company Name: Product Name: Product Version: 0.0.0.0Legal Copyright: Legal Trademarks: Original Filename: Chrome.exeInternal Name: Chrome.exeFile Version: 0.0.0.0File Description: Comments: Language: English (United States)

PE Sections

Name	Virtual Address	Virtual Size	Raw Size	Entropy	Section MD5
.text	8192	548068	548352	2.95049	63273867f9ccd553d0918a6308be6fae
.rsrc	557056	672	1024	1.48043	05708c48d5ea0f6b2b485acf35364f95
.reloc	565248	12	512	0.070639	c4891fef7e383c84449af82460469fc3

Dropped from:

Downloaded by:

Similar by SSDeep:

Similar by Lavasoft Polymorphic Checker:

Network Activity

URLs

IDS verdicts (Suricata alerts: Emerging Threats ET ruleset)

Traffic

Map

The Backdoor connects to the servers at the folowing location(s):

Strings from Dumps

notepad.exe_436:

.text

.text

`.data

`.data

.rsrc

.rsrc

comdlg32.dll

comdlg32.dll

SHELL32.dll

SHELL32.dll

WINSPOOL.DRV

WINSPOOL.DRV

COMCTL32.dll

COMCTL32.dll

msvcrt.dll

msvcrt.dll

ADVAPI32.dll

ADVAPI32.dll

KERNEL32.dll

KERNEL32.dll

NTDLL.DLL

NTDLL.DLL

GDI32.dll

GDI32.dll

USER32.dll

USER32.dll

notepad.chm

notepad.chm

hhctrl.ocx

hhctrl.ocx

CLSID\{ADB880A6-D8FF-11CF-9377-00AA003B7A11}\InprocServer32

CLSID\{ADB880A6-D8FF-11CF-9377-00AA003B7A11}\InprocServer32

notepad.pdb

notepad.pdb

t%SSh

t%SSh

_acmdln

_acmdln

RegCloseKey

RegCloseKey

RegCreateKeyW

RegCreateKeyW

RegOpenKeyExA

RegOpenKeyExA

SetViewportExtEx

SetViewportExtEx

GetKeyboardLayout

GetKeyboardLayout

name="Microsoft.Windows.Shell.notepad"

name="Microsoft.Windows.Shell.notepad"

version="5.1.0.0"

version="5.1.0.0"

<description>Windows Shell</description>

<description>Windows Shell</description>

name="Microsoft.Windows.Common-Controls"

name="Microsoft.Windows.Common-Controls"

version="6.0.0.0"

version="6.0.0.0"

publicKeyToken="6595b64144ccf1df"

publicKeyToken="6595b64144ccf1df"

&*$#$$#$*

&*$#$$#$*

MMMrMMM`MMMRMMMFMMM:MMM.MMM"MMM

MMMrMMM`MMMRMMMFMMM:MMM.MMM"MMM

*.txt

*.txt

/.SETUP

/.SETUP

5.1.2600.5512 (xpsp.080413-2105)

5.1.2600.5512 (xpsp.080413-2105)

NOTEPAD.EXE

NOTEPAD.EXE

Windows

Windows

Operating System

Operating System

5.1.2600.5512

5.1.2600.5512

notepad.hlp

notepad.hlp

Text Documents (*.txt)

Text Documents (*.txt)

You cannot quit Windows because the Save As dialog

You cannot quit Windows because the Save As dialog

dialog box, and then try quitting Windows again.

dialog box, and then try quitting Windows again.

Common Dialog error (0xx)

Common Dialog error (0xx)

Not enough memory available to complete this operation. Quit one or more applications to increase available memory, and then try again.KThe %% file is too large for Notepad.

Not enough memory available to complete this operation. Quit one or more applications to increase available memory, and then try again.KThe %% file is too large for Notepad.

Not a valid file name.MCannot create the %% file.

Not a valid file name.MCannot create the %% file.

Make sure that the path and filename are correct.RCannot carry out the Word Wrap command because there is too much text in the file.

Make sure that the path and filename are correct.RCannot carry out the Word Wrap command because there is too much text in the file.

Page %d

Page %d

Ln %d, Col %d

Ln %d, Col %d

notepad.exe_436_rwx_10000000_0004A000:

.idata

.idata

.rdata

.rdata

P.reloc

P.reloc

P.rsrc

P.rsrc

ServerKeyloggerU

ServerKeyloggerU