PE_QUERVAR.D-O

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.

It creates folders where it drops its files. It injects its dropped file/component to specific processes.

It creates an infection marker in infected files.

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 drops the following component file(s):

• %User Profile%\Application Data\{Random Folder}\{Random File name}.EXE.LNK
• %User Profile%\Application Data\{Random Folder}\{Random File name}.EXE.INI

(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.)

It drops and executes the following files:

• %User Profile%\Application Data\{Random folder}\{Random File name}.exe - detected as PE_QUERVAR.D-0

(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.)

It creates the following folders:

• %User Profile%\Application Data\{Random Folder}

(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.)

It injects its dropped file/component to the following processes:

• csrss.exe

It terminates itself if it finds the following processes in the affected system's memory:

• taskmgr.exe

Autostart Technique

This file infector modifies the following registry entry(ies) to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Windows
Load = "%User Profile%\Application Data\{Random Folder}\{Random Filename}.EXE.LNK"

(Note: The default value data of the said registry entry is "".)

File Infection

This file infector infects the following file types:

• EXE
• DOC
• DOCX
• XLS
• XLSX

It creates an infection marker in infected files.

Other Details

This file infector connects to the following possibly malicious URL:

• http://windows{BLOCKED}soft.com/update.apx
• http://{BLOCKED}w.com.br/includes/domit/way.php
• http://www.{BLOCKED}kes.com/way.php

NOTES:

This file infector renames the extension of the infected file as follows:

• .DOC to .COD.SCR
• .DOCX to .XCOD.SCR
• .XLS to .SLX.SCR
• .XLSX to .XSLX.SCR

It then deletes the original copy of the infected files. The infected files are already detected by Trend Micro as PE_QUERVAR.D.