Analysis by: Michael Cabel

 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

This Trojan is noteworthy as it arrives as an attachment to a spam message professing to be from Bobijou Inc., an online jewelry shop. This message directs recipients to the attachment by indicating it as a file containing their order details. Attackers use a dictionary attack to generate a list of recipients for the spam.

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 executes then deletes itself afterward.

It executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size: Varies
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 25 Apr 2011
Payload: Downloads files

Arrival Details

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

Installation

This Trojan executes then deletes itself afterward.

It injects threads into the following normal process(es):

  • SVCHOST.EXE

Download Routine

This Trojan connects to the following website(s) to download and execute a malicious file:

  • http://{BLOCKED}tov.com/pusk.exe
  • http://{BLOCKED}plyaga.ru/pusk.exe
  • http://{BLOCKED}yeyayca.ru/pusk.exe

It saves the files it downloads using the following names:

  • %User Temp%\pusk.exe - detected by Trend Micro as TROJ_FAKEAV.ZZJ

(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.)

It then executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://{BLOCKED}rs.net/f/g.php

However, as of this writing, the said sites are inaccessible.

NOTES:

It bears the icon of the following application:

  • PDF document

  SOLUTION

Minimum Scan Engine: 8.900
FIRST VSAPI PATTERN FILE: 8.120.11
FIRST VSAPI PATTERN DATE: 26 Apr 2011
VSAPI OPR PATTERN File: 8.121.00
VSAPI OPR PATTERN Date: 26 Apr 2011

Step 1

For Windows ME and XP 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 TROJ_DLOADR.ZZJ

Step 3

Scan your computer with your Trend Micro product to delete files detected as TROJ_DLOADR.ZZJ 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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