Threat Encyclopedia

HTML_SHELLCOD.SM

Publish date: December 22, 2010

ANALYSIS BY

Karl Dominguez


PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type:Trojan

  • Destructiveness:No

  • Encrypted: Yes

  • In the wild: Yes

OVERVIEW


This malware exploits a vulnerability in Internet Explorer to enable remote attackers to execute arbitrary commands on the affected system. The said vulnerability is addressed in the bulletin (MS10-090) Cumulative Security Update for Internet Explorer (2416400).

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

This Trojan takes advantage of a vulnerability in Internet Explorer 6, 7, and 8 and allows remote attackers to execute arbitrary code.

After succesfully exploiting the said vulnerability, it connects to URLs to download other malicious files detected as TROJ_LAMECHI.D, JS_EXPLOIT.ADA, JS_EXPLOIT.SM1, TROJ_DLOADR.DAM, TROJ_GAMETHI.FMS, PE_PARITE.A and TSPY_ARDAMAX.HR.

This Trojan executes when a user accesses certain websites where it is hosted.

TECHNICAL DETAILS

File Size:

Varies

File Type:

HTML, HTM

Memory Resident:

No

Initial Samples Received Date:

17 Dec 2010

Payload:

Downloads files

Arrival Details

This Trojan executes when a user accesses certain websites where it is hosted.

Download Routine

This Trojan takes advantage of the following software vulnerabilities to download possibly malicious files:

  • Uninitialized Memory Corruption Vulnerability (CVE-2010-3962) in Internet Explorer

After successfully exploiting the said vulnerability, this malware connects to the following URLs to possibly download other malicious files:

  • http://{BLOCKED}M.INFO/add.exe - detected by Trend Micro as TROJ_LAMECHI.D
  • http://www.{BLOCKED}t.com/360safe.html - detected by Trend Micro as JS_EXPLOIT.ADA
  • http://www.{BLOCKED}t.com/360.html - detected by Trend Micro as JS_EXPLOIT.SM1
  • http://www.{BLOCKED}t.com/361.html - HTML_SHELLCOD.SM
  • http://www.{BLOCKED}t.com/360safe.css - detected by Trend Micro as TROJ_DLOADR.DAM
  • www.{BLOCKED}m.com/lsearch/help.exe - detected by Trend Micro as TROJ_GAMETHI.FMS
  • http://{BLOCKED}n.live.com.mailadword.com/update.exe - detected by Trend Micro as PE_PARITE.A
  • http://h1.{BLOCKED}y.com/oofa/xp.exe - detected by Trend Micro as TSPY_ARDAMAX.HR
  • http://www.{BLOCKED}ool.info/n.exe - non malicious
  • http://{BLOCKED}n.cnzz.com/pic.gif - non malicious
  • http://www.{BLOCKED}lub.com/reg/linkbl.gif - inaccessible
  • {BLOCKED}chid.net/bbs/icon/c.exe - inaccessible
  • {BLOCKED}.{BLOCKED}.11.71/Styles/x.exe - inaccessible

Other Details

More information on this vulnerability can be found below:

It does the following:

  • Other variants of this malware execute a command shell to possibly download other files from the hosting website:
    • cmd.exe /C FOR /R ""%User Profile%\"" %i IN (scvhost*.txt) DO %i"

(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)

SOLUTION

Minimum Scan Engine:

8.900

VSAPI OPR PATTERN File:

7.719.00

VSAPI OPR PATTERN Date:

22 Dec 2010

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

Remove malware files dropped/downloaded by HTML_SHELLCOD.SM

    • TROJ_LAMECHI.D
    • JS_EXPLOIT.ADA
    • JS_EXPLOIT.SM1
    • TROJ_DLOADR.DAM
    • TROJ_GAMETHI.FMS
    • PE_PARITE.A
    • TSPY_ARDAMAX.HR

Step 3

Close all opened browser windows

Step 4

Scan your computer with your Trend Micro product to delete files detected as HTML_SHELLCOD.SM. 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.

Step 5

Download and apply this security patch Refrain from using these products until the appropriate patches have been installed. Trend Micro advises users to download critical patches upon release by vendors.


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