TROJ_FAKEMS.CA

 Analysis by: Rika Joi Gregorio

 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Dropped by other malware

This malware is involved with a spam attack during January 2013. It arrives as a dropped file from a spammed mail with the body written in the Japanese language and bearing the subject New Year Greetings. It appends garbage code to the copy it drops in order to avoid detection.

To get a one-glance comprehensive view of the behavior of this Trojan, refer to the Threat Diagram shown below.

This Trojan may be dropped by other malware.

It executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system. As of this writing, the said sites are inaccessible.

It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size:

55,219,364 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

10 Jan 2013

Payload:

Drops files, Downloads files

Arrival Details

This Trojan may be dropped by the following malware:

  • TROJ_DROPPER.AJM

Installation

This Trojan drops the following copies of itself into the affected system and executes them:

  • %Program Files%\Windows NT\Accessories\Microsoft\mslives.exe

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)

Autostart Technique

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

HKLM\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
msliveupdate = "%Program Files%\Windows NT\Accessories\Microsoft\mslives.exe"

Download Routine

This Trojan connects to the following website(s) to download and execute a malicious file:

  • http://www.{BLOCKED}a-group.co.jp/news/topics.html

It saves the files it downloads using the following names:

  • %User Temp%\mscxml.exe

(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, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)

It then executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

As of this writing, the said sites are inaccessible.

Other Details

This Trojan deletes the initially executed copy of itself

NOTES:

This Trojan checks if the full path of the current running process is %Program Files%\Windows NT\Accessories\Microsoft\mslives.exe. If so, it will download a file. But if the full path is different, it will drop a copy of itself, %Program Files%\Windows NT\Accessories\Microsoft\mslives.exe, and execute it afterwards.

Also, it drops copies of itself in various file size, appending garbage codes, to avoid easy detection.

  SOLUTION

Minimum Scan Engine:

9.300

FIRST VSAPI PATTERN FILE:

9.648.06

FIRST VSAPI PATTERN DATE:

10 Jan 2013

VSAPI OPR PATTERN File:

9.649.00

VSAPI OPR PATTERN Date:

11 Jan 2013

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

Remove malware/grayware files that dropped/downloaded TROJ_FAKEMS.CA

Step 3

Restart in Safe Mode

[ Learn More ]

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • msliveupdate = "%Program Files%\Windows NT\Accessories\Microsoft\mslives.exe"

Step 5

Search and delete this file

[ 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%\mscxml.exe

Step 6

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


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