Analysis by: Sabrina Lei Sioting
 Modified 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:

  • In the wild: Yes

  TECHNICAL DETAILS

File Size: 60,928 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 21 Jun 2011

Installation

This Trojan drops the following copies of itself into the affected system:

  • %System%\ac32.exe

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

It drops the following file(s)/component(s):

  • %User Temp%\1_co.txt
  • %User Temp%\ac32_co.txt
  • %User Temp%\ac32.bat

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
ac32 = "%System%\ac32.exe"

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://{BLOCKED}ads.com/cpv.jsp?p=113890&aid=10036145&partnerMin=0.00&ron=on&ronMin=0.00&url=&context=&default=http://{BLOCKED}k.mdmads.com/ads.php
  • http://{BLOCKED}ads.com/cresults.jsp?p=113890&aid=10036145&partnerMin=0.00&ron=on&ronMin=0.00&url=&context=&default=http://{BLOCKED}k.mdmads.com/ads.php&ip=120.89.55.3
  • http://{BLOCKED}ads.com/cresults.jsp?p=113890&aid=10036145&partnerMin=0.00&ron=on&ronMin=0.00&url=&context=&default=http://{BLOCKED}k.mdmads.com/ads.php&ip=120.89.55.3
  • http://{BLOCKED}otocard.com/geo/countrybyip.php
  • http://www.{BLOCKED}archresults.com/
  • http://www.{BLOCKED}archresults.com/images/472.jpg
  • http://www.{BLOCKED}archresults.com/templates/default/styles.css

  SOLUTION

Minimum Scan Engine: 8.900
FIRST VSAPI PATTERN FILE: 8.237.00
FIRST VSAPI PATTERN DATE: 21 Jun 2011

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

Identify and terminate files detected as TROJ_KRYPTO.SMIQ

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 3

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
    • ac32 = %System%\ac32.exe

Step 4

Search and delete these files

[ Learn More ]
There may be some component files 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.
  • %User Temp%\1_co.txt
  • %User Temp%\ac32_co.txt
  • %User Temp%\ac32.bat

Step 5

Scan your computer with your Trend Micro product to delete files detected as TROJ_KRYPTO.SMIQ. 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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