ALIASES:

Virus:Win32/Azero.A (Microsoft); Downloader-CGI (McAfee); W32.SillyFDC (Symantec); Trojan-Downloader.Win32.Tolsty.a, Trojan-Downloader.Win32.VB.cse (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Virus:W32/Varp.gen!A (FSecure)

 PLATFORM:

Windows 2000, Windows, XP, Windows Server 2003

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

  • Threat Type: File infector

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This file infector arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

  TECHNICAL DETAILS

File Size: 166,914 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 05 Dec 2011

Arrival Details

This file infector arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Installation

This file infector creates the following folders:

  • %User Profile%\Applications Data
  • %User Profile%\Applications Data\Microsoft
  • %User Profile%\Applications Data\Media Player
  • %User Profile%\Applications Data\Office
  • %User Profile%\Applications Data\Word
  • %User Profile%\Applications Data\Excel
  • %User Profile%\Applications Data\Windows

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

Dropping Routine

This file infector drops the following files:

  • %System%\maxtrox.txt
  • %Desktop%.ini

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.. %Desktop% is the current user's desktop, which is usually C:\Documents and Settings\{User Name}\Desktop on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\Desktop on Windows Vista and 7.)

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine: 9.200

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

Search and delete these folders

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %User Profile%\Applications Data
  • %User Profile%\Applications Data\Microsoft
  • %User Profile%\Applications Data\Media Player
  • %User Profile%\Applications Data\Office
  • %User Profile%\Applications Data\Word
  • %User Profile%\Applications Data\Excel
  • %User Profile%\Applications Data\Windows

Step 3

Search and delete these components

[ Learn More ]
There may be some components 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.
  • %System%\maxtrox.txt
  • %Desktop%.ini

Step 4

Scan your computer with your Trend Micro product to clean files detected as PE_AZERO.A. 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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