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HTML_EXPDROP.II
Aliases: Exploit:Win32/Dufmoh.A (Microsoft), Bloodhound.Exploit.474 (Symantec), Exploit-IEexecCommand (McAfee), Trojan-Downloader.HTML.SWFLoad.g (Kaspersky)
Malware type: Trojan
Destructive: No
Platform: Windows 2000, Windows XP, Windows Server 2003
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 Release Date: 18 Sep 2012
VSAPI OPR Pattern Version: 9.403.00
VSAPI OPR Pattern Release 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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Analysis By: Cris Nowell Pantanilla
Modified By: Christopher Daniel So

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