arrow_back
search
close

TROJ_RANSOM.DSU

January 27, 2013
 ALIASES:

Trojan:Win32/Tobfy.N (Microsoft); Trojan.Win32.Generic!BT (Sunbelt); Trojan horse Generic31.YEA (AVG)

 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:

79,352 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

27 Jan 2013

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:

  • %User Profile%\Application Data\ifgxpers.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.)

Other System Modifications

This Trojan adds the following registry keys:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Control\SafeBoot\mini

HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Control\SafeBoot\net

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion
path = "{malware path and file name}"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion
AdobeUpdaters = "%System%\svchost.exe"

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Adobe ARM = "%User Profile%\Application Data\ifgxpers.exe"

(Note: The default value data of the said registry entry is "%Program Files%\Common Files\Adobe\ARM\1.0\AdobeARM.exe".)

Dropping Routine

This Trojan drops the following files:

  • %User Profile%\Application Data\1.jpg
  • %User Profile%\Application Data\sound.mp3

(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.)

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://{BLOCKED}.107.212/n155p7khn8/upload/img.jpg

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.300

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

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\System\CurrentControlSet\Control\SafeBoot
    • mini
  • In HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\SafeBoot
    • net

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
    • path = "{malware path and file name}"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion
    • AdobeUpdaters = "%System%\svchost.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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • From: Adobe ARM = "%User Profile%\Application Data\ifgxpers.exe"
      To: Adobe ARM = """%Program Files%\Common Files\Adobe\ARM\1.0\AdobeARM.exe"""

Step 5

Search and delete these components

[ Learn More ]
There may be some components 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 Profile%\Application Data\1.jpg
  • %User Profile%\Application Data\sound.mp3

Step 6

Scan your computer with your Trend Micro product to delete files detected as TROJ_RANSOM.DSU. 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.


Did this description help? Tell us how we did.