Analysis by: Erika Bianca Mendoza
 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: File infector

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

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

It executes the dropped file(s). As a result, malicious routines of the dropped files are exhibited on the affected system.

  TECHNICAL DETAILS

File Size: Varies
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 13 Jan 2012

Arrival Details

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

Installation

This File infector drops the following file(s)/component(s):

  • %System%\system.exe - detected as TROJ_SCAR.SMP
  • %System%\{random1}.dll - detected as TROJ_FAKEAV.SM7
  • %System%\{random2}.dll - detected as TROJ_SPNR.14LR11

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

It drops the following non-malicious files:

  • %Current Directory%\{malware file name}.exe

It drops the following copies of itself into the affected system:

  • %Current Directory%\{malware file name}.exet

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
system = "%System%\system.exe"

Dropping Routine

This File infector executes the dropped file. As a result, malicious routines of the dropped file are exhibited on the affected system.

NOTES:
This is Trend Micro's detection for files that have been modified by another malware to contain malicious routines.

  SOLUTION

Minimum Scan Engine: 9.200

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 malware/grayware files dropped/downloaded by PE_BEGCBUG.A. (Note: Please skip this step if the threats listed below have already been removed.)

    • TROJ_SCAR.SMP
    • TROJ_FAKEAV.SM7
    • TROJ_SPNR.14LR11

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
    • system = "%System%\system.exe"

Step 5

Scan your computer with your Trend Micro product to clean files detected as PE_BEGCBUG.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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