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TROJ_DOWNLOADER_000007d.TOMA

October 10, 2012
 ALIASES:

TrojanDownloader:Win32/Wintrim.BX (Microsoft); Skintrim.gen.i (McAfee); Trojan.Gen (Symantec); Trojan-Downloader.Win32.Lipler.axkd (Kaspersky); Trojan-Downloader.Win32.Wintrim.bx (v) (Sunbelt); Adware:W32/Wintrim.gen!P (FSecure)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW


This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

  TECHNICAL DETAILS

File Size:

2,125,804 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

26 Sep 2012

Arrival Details

This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Installation

This Trojan creates the following folders:

  • %System Root%\DOCUME~1
  • %System Root%\DOCUME~1\ADMINI~1
  • %User Profile%\LOCALS~1
  • %User Temp%\nsf3.tmp
  • %Start Menu%\Programs\Games-Attack
  • %User Profile%\Application Data\Games-Attack

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.. %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.. %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003.. %Start Menu% is the current user's Start Menu folder, which is usually C:\Windows\Profiles\{user name}\Start Menu on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu on Windows NT and C:\Windows\Start Menu or C:\Documents and Settings\{User name}\Start Menu on Windows 2000, XP, and Server 2003.)

Autostart Technique

This Trojan adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
rokws = "%Application Data%\rokws.exe rokws"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
esqgetra = "%Application Data%\esqgetra.exe esqgetra"

Other System Modifications

This Trojan deletes the following files:

  • %User Temp%\nsk1.tmp
  • %User Temp%\nsf3.tmp
  • %Application Data%\rokws_navtmp.dat

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003.. %Application Data% is the current user's Application Data folder, which is usually C:\Windows\Profiles\{user name}\Application Data on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Application Data on Windows NT, and C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003.)

It adds the following registry keys:

HKEY_LOCAL_MACHINE\Software\Games-Attack

HKEY_CURRENT_USER\Software\Games-Attack

HKEY_CURRENT_USER\Software\fcn

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Uninstall\
rokws

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Uninstall\
esqgetra

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Games-Attack
dl_lg = "EN"

HKEY_CURRENT_USER\Software\Games-Attack
dl_lg = "EN"

HKEY_LOCAL_MACHINE\SOFTWARE\Games-Attack
grpid = "2046"

HKEY_CURRENT_USER\Software\Games-Attack
grpid = "2046"

HKEY_LOCAL_MACHINE\SOFTWARE\Games-Attack
installdt = "20100622"

HKEY_CURRENT_USER\Software\Games-Attack
installdt = "20100622"

HKEY_CURRENT_USER\Software\Games-Attack
uai = "http://www.{BLOCKED}attack.com/congratulation.php?lg=EN&grpid=2046"

HKEY_LOCAL_MACHINE\SOFTWARE\Games-Attack
dl_browser = "IE"

HKEY_CURRENT_USER\Software\Games-Attack
dl_browser = "IE"

HKEY_LOCAL_MACHINE\SOFTWARE\Games-Attack
dl_hp_url = "http://www.{BLOCKED}lsucher.com/?t=Q100622&s=h"

HKEY_CURRENT_USER\Software\Games-Attack
dl_hp_url = "http://www.{BLOCKED}lsucher.com/?t=Q100622&s=h"

HKEY_LOCAL_MACHINE\SOFTWARE\Games-Attack
dl_se_name = "Schnell Sucher"

HKEY_CURRENT_USER\Software\Games-Attack
dl_se_name = "Schnell Sucher"

HKEY_LOCAL_MACHINE\SOFTWARE\Games-Attack
dl_se_url = "http://www.{BLOCKED}lsucher.com/result.php?t=Q100622&s=b&keywords={searchTerms}"

HKEY_CURRENT_USER\Software\Games-Attack
dl_se_url = "http://www.{BLOCKED}lsucher.com/result.php?t=Q100622&s=b&keywords={searchTerms}"

HKEY_LOCAL_MACHINE\SOFTWARE\Games-Attack
dl_se_icon = "http://www.{BLOCKED}lsucher.com/favicon.ico"

HKEY_CURRENT_USER\Software\Games-Attack
dl_se_icon = "http://www.{BLOCKED}lsucher.com/favicon.ico"

HKEY_LOCAL_MACHINE\SOFTWARE\Games-Attack
ss_res = "http://download.{BLOCKED}attack.com/ss.php?lg=EN&grpid=2046"

HKEY_CURRENT_USER\Software\Games-Attack
ss_res = "http://download.{BLOCKED}attack.com/ss.php?lg=EN&grpid=2046"

HKEY_CURRENT_USER\Software\Games-Attack
_status = "ok"

HKEY_CURRENT_USER\Software\Games-Attack
uai = "http://www.{BLOCKED}attack.com/congratulation.php?lg=EN&grpid=2046&itype=1&res=1"

HKEY_LOCAL_MACHINE\SOFTWARE\Games-Attack
sp_id = "1"

HKEY_CURRENT_USER\Software\fcn
gid = "2046"

HKEY_CURRENT_USER\Software\fcn
cnid = "QMnzQSdYTB67QfB5WLPlyQ"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
rokws
DisplayName = "Favorit"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
rokws
UninstallString = "%Application Data%\rokws.exe -uninstall"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
rokws
NoRemove = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
rokws
NoModify = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
rokws
NoRepair = "1"

HKEY_CURRENT_USER\Software\fcn
idt = "201209261941"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
esqgetra
DisplayName = "Favorit"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
esqgetra
UninstallString = "%Application Data%\esqgetra.exe -uninstall"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
esqgetra
NoRemove = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
esqgetra
NoModify = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
esqgetra
NoRepair = "1"

It deletes the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
rokws

Dropping Routine

This Trojan drops the following files:

  • %User Temp%\nsk2.tmp
  • %User Temp%\nsf3.tmp\modern-header.bmp
  • %User Temp%\nsf3.tmp\modern-wizard.bmp
  • %User Temp%\nsf3.tmp\nsDialogs.dll
  • %User Temp%\nsf3.tmp\System.dll
  • %User Temp%\nsf3.tmp\header2.bmp
  • %User Temp%\nsf3.tmp\FavoritDE.rtf
  • %User Temp%\nsf3.tmp\FavoritEN.rtf
  • %User Temp%\nsf3.tmp\FavoritES.rtf
  • %User Temp%\nsf3.tmp\FavoritFR.rtf
  • %User Temp%\nsf3.tmp\FavoritIT.rtf
  • %Application Data%\rokws.exe
  • %Desktop%\Games-Attack.lnk
  • %Start Menu%\Programs\Games-Attack\Games-Attack.lnk
  • %Start Menu%\Programs\Games-Attack\Uninstall.lnk
  • %User Temp%\nsf3.tmp\NSISdl.dll
  • %User Temp%\GA.zip
  • %Application Data%\rokws.dat
  • %Application Data%\rokws_navps.dat
  • %Application Data%\rokws_m2s.xml
  • %Application Data%\rokws_m2s.zl
  • %Application Data%\rokws_s2m.zl
  • %Application Data%\rokws_s2m.xml
  • %Application Data%\esqgetra.exe
  • %Application Data%\rokws_navup.dat
  • %Application Data%\esqgetra.dat
  • %Application Data%\esqgetra_navps.dat
  • %Application Data%\esqgetra_nav.dat
  • %Application Data%\esqgetra_navup.dat

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003.. %Application Data% is the current user's Application Data folder, which is usually C:\Windows\Profiles\{user name}\Application Data on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Application Data on Windows NT, and C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003.. %Desktop% is the current user's desktop, which is usually C:\Windows\Profiles\{user name}\Desktop on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Desktop on Windows NT, and C:\Documents and Settings\{User Name}\Desktop on Windows 2000, XP, and Server 2003.. %Start Menu% is the current user's Start Menu folder, which is usually C:\Windows\Profiles\{user name}\Start Menu on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu on Windows NT and C:\Windows\Start Menu or C:\Documents and Settings\{User name}\Start Menu on Windows 2000, XP, and Server 2003.)

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://download.{BLOCKED}t-network.com/binaries/download.php
  • http://updates.{BLOCKED}-network.com/sa/cpi.php?{random characters}
  • http://updates.{BLOCKED}-network.com/sa/receive_data.php
  • http://updates.{BLOCKED}-network.com/binaries/bin.php?id=0&up=1&fd=1
  • http://updates.{BLOCKED}-network.com/cn/cnconfig.php?vs=&country=&did=&grp=2046&pid=
  • http://updates.{BLOCKED}-network.com/binaries/check.php

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.200

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Restart in Safe Mode

[ Learn More ]

Step 3

Delete this registry key

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\Software
    • Games-Attack
  • In HKEY_CURRENT_USER\Software
    • Games-Attack
  • In HKEY_CURRENT_USER\Software
    • fcn
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Uninstall
    • rokws
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Uninstall
    • esqgetra

Step 4

Delete this registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • rokws = "%Application Data%\rokws.exe rokws"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • esqgetra = "%Application Data%\esqgetra.exe esqgetra"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Games-Attack
    • dl_lg = "EN"
  • In HKEY_CURRENT_USER\Software\Games-Attack
    • dl_lg = "EN"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Games-Attack
    • grpid = "2046"
  • In HKEY_CURRENT_USER\Software\Games-Attack
    • grpid = "2046"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Games-Attack
    • installdt = "20100622"
  • In HKEY_CURRENT_USER\Software\Games-Attack
    • installdt = "20100622"
  • In HKEY_CURRENT_USER\Software\Games-Attack
    • uai = "http://www.{BLOCKED}attack.com/congratulation.php?lg=EN&grpid=2046"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Games-Attack
    • dl_browser = "IE"
  • In HKEY_CURRENT_USER\Software\Games-Attack
    • dl_browser = "IE"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Games-Attack
    • dl_hp_url = "http://www.{BLOCKED}lsucher.com/?t=Q100622&s=h"
  • In HKEY_CURRENT_USER\Software\Games-Attack
    • dl_hp_url = "http://www.{BLOCKED}lsucher.com/?t=Q100622&s=h"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Games-Attack
    • dl_se_name = "Schnell Sucher"
  • In HKEY_CURRENT_USER\Software\Games-Attack
    • dl_se_name = "Schnell Sucher"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Games-Attack
    • dl_se_url = "http://www.{BLOCKED}lsucher.com/result.php?t=Q100622&s=b&keywords={searchTerms}"
  • In HKEY_CURRENT_USER\Software\Games-Attack
    • dl_se_url = "http://www.{BLOCKED}lsucher.com/result.php?t=Q100622&s=b&keywords={searchTerms}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Games-Attack
    • dl_se_icon = "http://www.{BLOCKED}lsucher.com/favicon.ico"
  • In HKEY_CURRENT_USER\Software\Games-Attack
    • dl_se_icon = "http://www.{BLOCKED}lsucher.com/favicon.ico"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Games-Attack
    • ss_res = "http://download.{BLOCKED}attack.com/ss.php?lg=EN&grpid=2046"
  • In HKEY_CURRENT_USER\Software\Games-Attack
    • ss_res = "http://download.{BLOCKED}attack.com/ss.php?lg=EN&grpid=2046"
  • In HKEY_CURRENT_USER\Software\Games-Attack
    • _status = "ok"
  • In HKEY_CURRENT_USER\Software\Games-Attack
    • uai = "http://www.{BLOCKED}attack.com/congratulation.php?lg=EN&grpid=2046&itype=1&res=1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Games-Attack
    • sp_id = "1"
  • In HKEY_CURRENT_USER\Software\fcn
    • gid = "2046"
  • In HKEY_CURRENT_USER\Software\fcn
    • cnid = "QMnzQSdYTB67QfB5WLPlyQ"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\rokws
    • DisplayName = "Favorit"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\rokws
    • UninstallString = "%Application Data%\rokws.exe -uninstall"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\rokws
    • NoRemove = "0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\rokws
    • NoModify = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\rokws
    • NoRepair = "1"
  • In HKEY_CURRENT_USER\Software\fcn
    • idt = "201209261941"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\esqgetra
    • DisplayName = "Favorit"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\esqgetra
    • UninstallString = "%Application Data%\esqgetra.exe -uninstall"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\esqgetra
    • NoRemove = "0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\esqgetra
    • NoModify = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\esqgetra
    • NoRepair = "1"

Step 5

Search and delete these files

[ Learn More ]
There may be some component files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.
  • %User Temp%\nsk2.tmp
  • %User Temp%\nsf3.tmp\modern-header.bmp
  • %User Temp%\nsf3.tmp\modern-wizard.bmp
  • %User Temp%\nsf3.tmp\nsDialogs.dll
  • %User Temp%\nsf3.tmp\System.dll
  • %User Temp%\nsf3.tmp\header2.bmp
  • %User Temp%\nsf3.tmp\FavoritDE.rtf
  • %User Temp%\nsf3.tmp\FavoritEN.rtf
  • %User Temp%\nsf3.tmp\FavoritES.rtf
  • %User Temp%\nsf3.tmp\FavoritFR.rtf
  • %User Temp%\nsf3.tmp\FavoritIT.rtf
  • %Application Data%\rokws.exe
  • %Desktop%\Games-Attack.lnk
  • %Start Menu%\Programs\Games-Attack\Games-Attack.lnk
  • %Start Menu%\Programs\Games-Attack\Uninstall.lnk
  • %User Temp%\nsf3.tmp\NSISdl.dll
  • %User Temp%\GA.zip
  • %Application Data%\rokws.dat
  • %Application Data%\rokws_navps.dat
  • %Application Data%\rokws_m2s.xml
  • %Application Data%\rokws_m2s.zl
  • %Application Data%\rokws_s2m.zl
  • %Application Data%\rokws_s2m.xml
  • %Application Data%\esqgetra.exe
  • %Application Data%\rokws_navup.dat
  • %Application Data%\esqgetra.dat
  • %Application Data%\esqgetra_navps.dat
  • %Application Data%\esqgetra_nav.dat
  • %Application Data%\esqgetra_navup.dat

Step 6

Search and delete these folders

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %System Root%\DOCUME~1
  • %System Root%\DOCUME~1\ADMINI~1
  • %User Profile%\LOCALS~1
  • %User Temp%\nsf3.tmp
  • %Start Menu%\Programs\Games-Attack
  • %User Profile%\Application Data\Games-Attack

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_DOWNLOADER_000007d.TOMA. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.

Step 8

Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.

  • %User Temp%\nsk1.tmp
  • %User Temp%\nsf3.tmp
  • %Application Data%\rokws_navtmp.dat

Step 9

Restore these deleted registry keys/values from backup

*Note: Only Microsoft-related keys/values will be restored. If the malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall
    • rokws


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