Skip to content

Export page to PDF
BKDR_PRESHIN.JTT
Malware type: Backdoor
Destructive: No
Platform: Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)
Encrypted: Yes
In the wild: Yes

Overview


Infection Channel: Downloaded from the Internet, Dropped by other malware

This backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites. It may be downloaded from remote sites by other malware.

It executes commands from a remote malicious user, effectively compromising the affected system.

It steals certain information from the system and/or the user.

Technical Details


File size: 153,472 bytes
File type: EXE
Memory resident: Yes
Initial samples received date: 09 May 2014
Payload: Connects to URLs/IPs, Compromises system security, Steals information

Arrival Details

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

It may be downloaded from remote site(s) by the following malware:

  • TROJ_PRESHIN.JTT

Installation

This backdoor drops the following file(s)/component(s):

  • %User Profile%\set.ini - encrypted component
  • %User Profile%\rundll32.exe
  • %User Profile%\dbgeng.dll
  • %User Temp%\{random}ptd.bat - deleted after execution. This contains commands to list system information

(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.. %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 adds the following processes:

  • iexplore.exe

It adds the following mutexes to ensure that only one of its copies runs at any one time:

  • Ultro_ISO_0369

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
dllhost services = "%User Profile%\rundll32.exe"

Backdoor Routine

This backdoor executes the following commands from a remote malicious user:

  • Download and execute arbitrary file
  • Download file

It connects to the following URL(s) to send and receive commands from a remote malicious user:

  • http://{BLOCKED}.{BLOCKED}.3.122:8080/logon.php?{random value}

Download Routine

This backdoor saves the files it downloads using the following names:

  • %User Temp%\{random}up.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, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)

Information Theft

This backdoor steals the following information:

  • IP configuration
  • List of running services
  • Network connections
  • List of computers in current domain

Stolen Information

This backdoor saves the stolen information in the following file:

  • %User Temp%\wg{number}.dat - deleted afterwards

(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.)

NOTES:
It steals passwords stored related to the following:

  • MS Outlook
  • Internet Explorer

Solution


Minimum scan engine: 9.700
First VSAPI Pattern File: 10.784.07
First VSAPI Pattern Release Date: 09 May 2014
VSAPI OPR Pattern Version: 10.785.00
VSAPI OPR Pattern Release Date: 09 May 2014

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 the malware/grayware file that dropped/downloaded BKDR_PRESHIN.JTT. (Note: Please skip this step if the threat(s) listed below have already been removed.)

     
    • TROJ_PRESHIN.JTT

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • dllhost services = "%User Profile%\rundll32.exe"

Step 5

Search and delete these files

[ Learn more ]
There may be some 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 Profile%\set.ini
  • %User Profile%\rundll32.exe
  • %User Profile%\dbgeng.dll

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_PRESHIN.JTT. 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.
Analysis By: Rhena Inocencio

Connect with us on