Analysis by: Homer Pacag
ALIASES:

W32/Kryptik.DJDI!tr (Fortinet)

 PLATFORM:

Windows

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

  • Threat Type: Spyware

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet

This spyware may be unknowingly downloaded by a user while visiting malicious websites.

It retrieves specific information from the affected system.

It deletes itself after execution.

  TECHNICAL DETAILS

File Size: 258,560 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 26 May 2015
Payload: Steals information

Arrival Details

This spyware may be unknowingly downloaded by a user while visiting malicious websites.

Installation

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

  • %User Temp%:defrag.scr - Alternate Data Stream (ADS) copy

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

It drops and executes the following files:

  • %User Temp%:defrag.vbs - Alternate Data Stream (ADS) This script executes %User Temp%:defrag.scr

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

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

  • 613fe04053ca4e05a0590440b98b2e59

Autostart Technique

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

HKLM\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Defrag = wscript "%User Temp%:defrag.vbs"

Information Theft

This spyware retrieves the following information from the affected system:

  • Usename
  • OS Version
  • Credit Card Information

Other Details

This spyware deletes itself after execution.

NOTES:

It connects to certain websites to send information:

  • {BLOCKED}infou48.ru/derpos/gateway.php
  • {BLOCKED}naciale8h.ru/derpos/gateway.php
  • {BLOCKED}sk7r.ru/derpos/gateway.php

  SOLUTION

Minimum Scan Engine: 9.750
FIRST VSAPI PATTERN FILE: 11.692.05
FIRST VSAPI PATTERN DATE: 26 May 2015
VSAPI OPR PATTERN File: 11.693.00
VSAPI OPR PATTERN Date: 26 May 2015

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

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

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
    • Defrag = wscript "%User Temp%:defrag.vbs"

Step 5

To delete ADS files:

  1. Download Streams.exe from this Microsoft page.
  2. Extract the contents of this file to a location of your choice.
  3. Open a command prompt window. To do this:
    • On Windows 2000, XP, and Server 2003:
      Click Start>Run. In the input box, type CMD, and press Enter.
    • On Windows Vista, 7, and Server 2008:
      Click the Windows button, type CMD in the search box, and press Enter.
    • On Windows 8, 8.1, and Server 2012:
      Right-click on the lower-left corner of the screen, click Command Prompt.
  4. In the command prompt, type the following, then press Enter:
    CD {Path where contents of downloaded file was extracted}
  5. Still in the command prompt type the following then press Enter:
    Streams.exe -d
    • %User Temp%:defrag.scr
    • %User Temp%:defrag.vbs
  6. Type exit then press Enter.

Step 6

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