Analysis by: Roland Marco Dela Paz
ALIASES:

TrojanDownloader:Win32/Chepvil.N (Microsoft); Trojan-Downloader.Win32.FraudLoad.ibu (Kaspersky)

 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

  OVERVIEW

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

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

It connects to certain websites to send and receive information. It deletes itself after execution.

  TECHNICAL DETAILS

File Size: 29,696 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 17 Aug 2011

Arrival Details

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

Installation

This Trojan adds the following processes:

  • %System%\svchost.exe

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)

Download Routine

This Trojan accesses the following websites to download files:

  • http://{BLOCKED}dfjnf.ru/pusk3.exe
  • http://{BLOCKED}nsfjg.ru/pusk3.exe

It saves the files it downloads using the following names:

  • %User Temp%\pusk3.exe

(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 website to send and receive information:

  • http://{BLOCKED}nsfjg.ru/ftp/g.php

It deletes itself after execution.

  SOLUTION

Minimum Scan Engine: 8.900
FIRST VSAPI PATTERN FILE: 8.360.07
FIRST VSAPI PATTERN DATE: 17 Aug 2011

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

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%\pusk3.exe

Step 3

Scan your computer with your Trend Micro product to delete files detected as TROJ_BREDO.LAC. 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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