Analysis by: Homer Pacag

ALIASES:

Trojan.Win32.Agentb.aekg (Kaspersky); Infostealer (Symantec); W32/Agentb.AEKG!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 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: 302,592 bytes
File Type: EXE
Memory Resident: Yes

Arrival Details

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

  • “%System%\wnhelp.exe

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

Autostart Technique

This spyware registers itself as a system service to ensure its automatic execution at every system startup by adding the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Windows Media Help
ImagePath = %System%\wnhelp.exe -services"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Windows Media Help
DisplayName = Windows Media Help

Information Theft

This spyware gathers the following data:

  • Process Name
  • Date and Time
  • Process ID
  • Credit Card Number

Stolen Information

The stolen information is saved in the following file:

  • %System%\prefb419.dat

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

Other Details

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

  • {malware path}\DebugConsole.log - contain activity logs

  SOLUTION

Minimum Scan Engine: 9.750
FIRST VSAPI PATTERN FILE: 11.488.04
FIRST VSAPI PATTERN DATE: 19 Feb 2015
VSAPI OPR PATTERN File: 11.489.00
VSAPI OPR PATTERN Date: 19 Feb 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 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.

 
  • HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Windows Media Help

Step 5

Search and delete this file

[ 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.
  • %System%\wnhelp.exe
  • %System%\prefb419.dat
  • {malware path}\DebugConsole.log

Step 6

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