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TROJ_DLDR.HB

March 22, 2013
 Analysis by: Christopher Daniel So
 ALIASES:

TrojanDownloader:Win32/Small.gen!AO (Microsoft)

 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet, Spammed via email


This malware is involved in the cyber attacks that targeted specific users in South Korea during March of 2013. It enters systems through a spammed mail purporting to come from a major banking organization. It downloads and runs malware on affected systems, which may result in malicious routines being exhibited.

To get a one-glance comprehensive view of the behavior of this Trojan, refer to the Threat Diagram shown below.

This Trojan arrives as an attachment to email messages spammed by other malware/grayware or malicious users. It 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:

212,992 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

20 Mar 2013

Payload:

Downloads files

Arrival Details

This Trojan arrives as an attachment to email messages spammed by other malware/grayware or malicious users.

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

Dropping Routine

This Trojan drops the following files:

  • %System%\inhtm.htm

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

Download Routine

This Trojan accesses the following websites to download files:

  • http://{BLOCKED}ges.adobe.com/www.adobe.com/ubi/template/identity/adobe/screen/gnav.css (saved as %System%\gscreem.exe)
  • http://{BLOCKED}85.com/uploads/fb9c6013f1b269b74c8cd139471b96fc/feng.jpg (saved as %System%\hzcompl.dll)
  • http://s1.{BLOCKED}n.net/editor/services/hanmailex/5.11.54/js/editorall.js (saved as %System%\logda.dat)
  • http://cardimage.{BLOCKED}ncard.com/img/email/general/btn_carduse.giff (saved as %System%\cutecat.gif)
  • hxxp://www.{BLOCKED}lower.net/board/images/start_car.gif (saved as %System%\{random file name}.dll) ) - detected as WORM_STTKR.A
  • http://{BLOCKED}daum.net/hanmailex-static/alarm/Notifier.swf (saved as %System%\hinredfh.exe)
  • http://{BLOCKED}g.nate.com/mail/img/button/btn_mycomputer.gif (saved as %System%\sotd.dll)
  • http://www.{BLOCKED}a.com/public/home_new/images/s/baidu.gif (saved as %System%\logdamain.dat)
  • http://www.{BLOCKED}oxylists.net/img/google.bmp (saved as %System%\tefrcft.gif)

NOTES:

This Trojan opens the dropped file %System%\inhtm.htm.

  SOLUTION

Minimum Scan Engine:

9.300

FIRST VSAPI PATTERN FILE:

9.800.05

FIRST VSAPI PATTERN DATE:

20 Mar 2013

VSAPI OPR PATTERN File:

9.801.00

VSAPI OPR PATTERN Date:

21 Mar 2013

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 TROJ_DLDR.HB

Step 3

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.
  • %System%\cutecat.gif
  • %System%\gscreem.exe
  • %System%\hinredfh.exe
  • %System%\hzcompl.dll
  • %System%\inhtm.htm
  • %System%\logda.dat
  • %System%\logdamain.dat
  • %System%\sotd.dll
  • %System%\tefrcft.gif

Step 4

Scan your computer with your Trend Micro product to delete files detected as TROJ_DLDR.HB. 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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