Analysis by: Mark Joseph Manahan
ALIASES:

Trojan:Win32/Mutopy.A (Microsoft), Win32/Rodecap.AT trojan (Eset), Trojan.Win32.Jorik.Mutopy.apr (Kaspersky)

 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: 556,544 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 16 Aug 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 adds the following folders:

  • %User Temp%\NwcTemp
  • %User Temp%\NwcTemp\ss51
  • %User Temp%\NwcTemp\ss52

(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 drops the following component file(s):

  • %User Temp%\NwcTemp\ss51\svchost.exe
  • %User Temp%\NwcTemp\ss52\svchost.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 drops the following copies of itself into the affected system:

  • {All User's Profile}\logman.exe
  • %User Profile%\Application Data\esentutl.exe
  • %User Profile%\Application Data\winlogon.exe
  • %Windows%\sessmgr.exe
  • %Windows%\spoolsv.exe
  • %Application Data%\mstinit.exe
  • %Application Data%\spoolsv.exe

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.. %Windows% is the Windows folder, which is usually C:\Windows.. %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)

Autostart Technique

This Trojan modifies the following registry entry(ies) to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Windows
load = "%Windows%\spoolsv.exe"

(Note: The default value data of the said registry entry is "".)

It creates the following registry entries to enable automatic execution of dropped component at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer\Run
Sessmgr = "%Windows%\sessmgr.exe""

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Windows
run = "%Application Data%\spoolsv.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\Run
Task Scheduler = "%Application Data%\mstinit.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Winlogon = "%User Profile%\Application Data\winlogon.exe"

HKEY_USERS\.DEFAULT\Software\
Microsoft\Windows\CurrentVersion\
Policies\Explorer\Run
Logman = "{All User's Profile}\logman.exe"

HKEY_USERS\.DEFAULT\Software\
Microsoft\Windows\CurrentVersion\
Run
EseNtUtl = "%User Profile%\Application Data\esentutl.exe"

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://bt2.{BLOCKED}t.org/a3a.php
  • http://bt2.{BLOCKED}t.org/a3i.php
  • http://fw.{BLOCKED}t.org/gu.php
  • http://getfree.{BLOCKED}apps.org/d/ss51.jpg
  • http://getfree.{BLOCKED}apps.org/d/ss52.jpg
  • http://seek4.{BLOCKED}t.org/img/seek.cgi?lin=10&db=ad08
  • http://seek4.{BLOCKED}t.org/img/seek.cgi?lin=10&db=f02
  • http://t2.{BLOCKED}t.org/d/t3.php
  • http://t2.{BLOCKED}t.org/d/t7.php
  • http://www.{BLOCKED}si.com/ncsi.txt

  SOLUTION

Minimum Scan Engine: 9.200
FIRST VSAPI PATTERN FILE: 9.328.01
FIRST VSAPI PATTERN DATE: 16 Aug 2012
VSAPI OPR PATTERN File: 9.329.00
VSAPI OPR PATTERN Date: 16 Aug 2012

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

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer\Run
    • Sessmgr = "%Windows%\sessmgr.exe""
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows
    • run = "%Application Data%\spoolsv.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\Explorer\Run
    • Task Scheduler = "%Application Data%\mstinit.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • Winlogon = "%User Profile%\Application Data\winlogon.exe"
  • In HKEY_USERS\.DEFAULT\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer\Run
    • Logman = "{All User's Profile}\logman.exe"
  • In HKEY_USERS\.DEFAULT\Software\Microsoft\Windows\CurrentVersion\Run
    • EseNtUtl = "%User Profile%\Application Data\esentutl.exe"

Step 4

Restore these modified registry values

[ Learn More ]

Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.

  • In HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows
    • From: load = "%Windows\spoolsv.exe""
      To: load = ""

Step 5

Search and delete this folder

[ 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.  
  • %User Temp%\NwcTemp

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.
 
  • %User Temp%\NwcTemp\ss51\svchost.exe
  • %User Temp%\NwcTemp\ss52\svchost.exe

Step 7

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