arrow_back
search
close

TROJ_SMALL.MJSM

October 12, 2012
 ALIASES:

TrojanDownloader:Win32/Small.gen!AO (Microsoft); Spy-Agent.gb (McAfee); Trojan.Gen (Symantec); PAK:UPX, Trojan-Dropper.Win32.StartPage.ebb (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); DeepScan:Generic.Malware.SdldspTkg.F9BEF2BC (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:

18,352 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

16 Dec 2011

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 drops the following copies of itself into the affected system:

  • %Program Files%\Common Files\sfbsbvx\coiome.exe

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files.)

It creates the following folders:

  • %Program Files%\Common Files\sfbsbvx
  • %User Profile%\Application Data\f.exe

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files.. %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.)

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
safe360 = "%Program Files%\Common Files\sfbsbvx\coiome.exe"

Other System Modifications

This Trojan deletes the following files:

  • %Program Files%\Common Files\sfbsbvx\coiome.exe
  • %Program Files%\VKT.hta
  • %Program Files%\Internet Explorer\usp10.dll
  • %Windows%\ModFan\mone.dll
  • %Windows%\UoDo\game.dll
  • %User Profile%\Cookies\index.dat
  • %Temporary Internet Files%\Content.IE5\index.dat
  • %Temporary Internet Files%\Content.IE5\2TPM8950\10_1_~1.HTM
  • %Temporary Internet Files%\Content.IE5\2TPM8950\16_1_~1.HTM
  • %Temporary Internet Files%\Content.IE5\2TPM8950\192168~1.HTM
  • %Temporary Internet Files%\Content.IE5\2TPM8950\192168~2.HTM
  • %Temporary Internet Files%\Content.IE5\2TPM8950\192168~3.HTM
  • %Temporary Internet Files%\Content.IE5\2TPM8950\192168~4.HTM
  • %Temporary Internet Files%\Content.IE5\2TPM8950\BOTTOM~1.PNG
  • %Temporary Internet Files%\Content.IE5\2TPM8950\BOX01_~1.GIF
  • %Temporary Internet Files%\Content.IE5\2TPM8950\BOX02_~1.GIF
  • %Temporary Internet Files%\Content.IE5\2TPM8950\BOX08_~1.GIF
  • %Temporary Internet Files%\Content.IE5\2TPM8950\B_1_~1.JPG
  • %Temporary Internet Files%\Content.IE5\2TPM8950\HEADER~1.GIF
  • %Temporary Internet Files%\Content.IE5\2TPM8950\JQUERY~1.JS
  • %Temporary Internet Files%\Content.IE5\2TPM8950\REPORT~1.PNG
  • %Temporary Internet Files%\Content.IE5\2TPM8950\TABLE_~1.PNG
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\10_1_~1.HTM
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\192168~1.HTM
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\192168~2.HTM
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\192168~3.HTM
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\192168~4.HTM
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\BOX07_~1.GIF
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\CALEND~1.JS
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\DROPDO~1.JPG
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\FOOTER~1.GIF
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\HEADER~1.JPG
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\IMPORT~1.PNG
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\TABLE_~2.PNG
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\TABLE_~1.PNG
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\TRANSP~1.GIF
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\10_1_~1.HTM
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\192168~1.HTM
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\192168~2.HTM
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\192168~3.HTM
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\192168~4.HTM
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\BACKGR~1.GIF
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\BOX03_~1.GIF
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\BOX04_~1.GIF
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\BOX06_~1.GIF
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\CONFIG~1.GIF
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\EDIT_I~1.PNG
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\JQUERY~1.JS
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\SANDBO~1.CSS
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\TOP_RI~1.PNG
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\192168~1.HTM
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\192168~2.HTM
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\192168~3.HTM
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\192168~4.HTM
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\1923A7~1.HTM
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\BOTTOM~1.PNG
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\BOX09_~1.GIF
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\DELETE~1.PNG
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\JQUERY~1.JS
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\OVERLI~1.JS
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\SUNBEL~1.JPG
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\TABLE_~1.PNG
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\TOP_LE~1.PNG
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\USERS_~1.PNG

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files.. %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.. %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.)

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
default_page_url = "http://www.{BLOCKED}ing.com"

It modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
Start Page = "http://www.{BLOCKED}ing.com"

(Note: The default value data of the said registry entry is http://www.microsoft.com/isapi/redir.dll?prd=ie&pver=6&ar=msnhome.)

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
Search Page = "http://www.{BLOCKED}ing.com"

(Note: The default value data of the said registry entry is http://www.microsoft.com/isapi/redir.dll?prd=ie&ar=iesearch.)

Dropping Routine

This Trojan drops the following files:

  • %Program Files%\LMR.hta
  • %Windows%\Fonts\om.ini
  • %Windows%\Tasks\LURg.vbe
  • %Windows%\Tasks\LURz.exe

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files.. %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.)

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://tj.{BLOCKED}0.com/t/Count.asp?{random characters}
  • http://n.{BLOCKED}0.com/b.jpg

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 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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • safe360="%Program Files%\Common Files\sfbsbvx\coiome.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
    • default_page_url="http://www.{BLOCKED}ing.com"

Step 4

Restore this modified 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\Internet Explorer\Main
    • From: Start Page="http://www.{BLOCKED}ing.com"
      To: Start Page=http://www.microsoft.com/isapi/redir.dll?prd=ie&pver=6&ar=msnhome
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
    • From: Search Page="http://www.{BLOCKED}ing.com"
      To: Search Page=http://www.microsoft.com/isapi/redir.dll?prd=ie&ar=iesearch

Step 5

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.
  • %Program Files%\Common Files\sfbsbvx
  • %User Profile%\Application Data\f.exe

Step 6

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.
  • %Program Files%\LMR.hta
  • %Windows%\Fonts\om.ini
  • %Windows%\Tasks\LURg.vbe
  • %Windows%\Tasks\LURz.exe

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_SMALL.MJSM. 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.

  • %Program Files%\Common Files\sfbsbvx\coiome.exe
  • %Program Files%\VKT.hta
  • %Program Files%\Internet Explorer\usp10.dll
  • %Windows%\ModFan\mone.dll
  • %Windows%\UoDo\game.dll
  • %User Profile%\Cookies\index.dat
  • %Temporary Internet Files%\Content.IE5\index.dat
  • %Temporary Internet Files%\Content.IE5\2TPM8950\10_1_~1.HTM
  • %Temporary Internet Files%\Content.IE5\2TPM8950\16_1_~1.HTM
  • %Temporary Internet Files%\Content.IE5\2TPM8950\192168~1.HTM
  • %Temporary Internet Files%\Content.IE5\2TPM8950\192168~2.HTM
  • %Temporary Internet Files%\Content.IE5\2TPM8950\192168~3.HTM
  • %Temporary Internet Files%\Content.IE5\2TPM8950\192168~4.HTM
  • %Temporary Internet Files%\Content.IE5\2TPM8950\BOTTOM~1.PNG
  • %Temporary Internet Files%\Content.IE5\2TPM8950\BOX01_~1.GIF
  • %Temporary Internet Files%\Content.IE5\2TPM8950\BOX02_~1.GIF
  • %Temporary Internet Files%\Content.IE5\2TPM8950\BOX08_~1.GIF
  • %Temporary Internet Files%\Content.IE5\2TPM8950\B_1_~1.JPG
  • %Temporary Internet Files%\Content.IE5\2TPM8950\HEADER~1.GIF
  • %Temporary Internet Files%\Content.IE5\2TPM8950\JQUERY~1.JS
  • %Temporary Internet Files%\Content.IE5\2TPM8950\REPORT~1.PNG
  • %Temporary Internet Files%\Content.IE5\2TPM8950\TABLE_~1.PNG
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\10_1_~1.HTM
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\192168~1.HTM
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\192168~2.HTM
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\192168~3.HTM
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\192168~4.HTM
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\BOX07_~1.GIF
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\CALEND~1.JS
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\DROPDO~1.JPG
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\FOOTER~1.GIF
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\HEADER~1.JPG
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\IMPORT~1.PNG
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\TABLE_~2.PNG
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\TABLE_~1.PNG
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\TRANSP~1.GIF
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\10_1_~1.HTM
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\192168~1.HTM
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\192168~2.HTM
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\192168~3.HTM
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\192168~4.HTM
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\BACKGR~1.GIF
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\BOX03_~1.GIF
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\BOX04_~1.GIF
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\BOX06_~1.GIF
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\CONFIG~1.GIF
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\EDIT_I~1.PNG
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\JQUERY~1.JS
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\SANDBO~1.CSS
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\TOP_RI~1.PNG
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\192168~1.HTM
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\192168~2.HTM
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\192168~3.HTM
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\192168~4.HTM
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\1923A7~1.HTM
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\BOTTOM~1.PNG
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\BOX09_~1.GIF
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\DELETE~1.PNG
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\JQUERY~1.JS
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\OVERLI~1.JS
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\SUNBEL~1.JPG
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\TABLE_~1.PNG
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\TOP_LE~1.PNG
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\USERS_~1.PNG


Did this description help? Tell us how we did.