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HTML_EXPDROP.II

September 17, 2012
 Analysis by: Cris Nowell Pantanilla
 Modified by: Christopher Daniel So
 ALIASES:

Exploit:Win32/Dufmoh.A (Microsoft), Bloodhound.Exploit.474 (Symantec), Exploit-IEexecCommand (McAfee), Trojan-Downloader.HTML.SWFLoad.g (Kaspersky)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

 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


This malicious HTML file exploits a zero-day vulnerability in Internet Explorer 7, 8, and 9. The exploit leads to the dropping of a PoisonIvy backdoor. PoisonIvy backdoors are known to be widely used in targeted malware attacks.

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

It then loads a malicious Flash file, Moh2010.swf. As a result, malicious routines of the component file are exhibited on the affected system. The malicious Flash file is detected by Trend Micro as either SWF_DROPPR.II, SWF_DROPPR.IJ, SWF_DROPPER.IK, or SWF_DROPPR.IL.

This Trojan may be hosted on a website and run when a user accesses the said website.

  TECHNICAL DETAILS

File Size:

Varies

File Type:

HTML, HTM

Initial Samples Received Date:

17 Sep 2012

Payload:

Executes files

Arrival Details

This Trojan may be hosted on a website and run when a user accesses the said website.

NOTES:

This malware checks the user's browser version. It targets Internet Explorer versions 7 and 8 on Windows XP. Some variants of this malware also targets Internet Explorer versions 8 and 9 on a 32-bit Windows 7 whose Java version is neither 6 nor 7.

It loads the malicious Flash file Moh2010.swf, which is detected by Trend Micro as one of the following:

  • SWF_DROPPR.II
  • SWF_DROPPR.IJ
  • SWF_DROPPR.IK
  • SWF_DROPPR.IL

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

9.402.03

FIRST VSAPI PATTERN DATE:

18 Sep 2012

VSAPI OPR PATTERN File:

9.403.00

VSAPI OPR PATTERN Date:

18 Sep 2012

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Close all opened browser windows

Step 3

Remove malware files dropped/downloaded by HTML_EXPDROP.II

Step 4

Scan your computer with your Trend Micro product to delete files detected as HTML_EXPDROP.II. 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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