PE_QUERVAR.A-O

October 09, 2012
 Analysis by: Sabrina Lei Sioting
 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: File infector

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet, Dropped by other malware, Infects files

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 prepends its codes to target files.

  TECHNICAL DETAILS

File Size:

99,328 bytes

File Type:

PE

Memory Resident:

Yes

Initial Samples Received Date:

29 May 2012

Payload:

Terminates processes

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 copies of itself into the affected system:

  • %Application Data%\Microsoft\{random}.exe
  • %Windows%\xpsp2res.dll

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Windows\Profiles\{user name}\Application Data on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Application Data on Windows NT, and C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003.. %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.)

It drops the following non-malicious file:

  • {Malware Path}\{random}.docx

File Infection

This file infector infects the following file types:

  • .doc
  • .docx
  • .exe

It prepends its codes to target files.

Process Termination

This file infector terminates the following processes if found running in the affected system's memory:

  • taskmgr.exe

NOTES:

This file infector avoids infecting files located in all logical drives that are labeled as the following:

  • CDROM drives
  • Unknown drives

If the file to be infected has the file extension .doc or .docx, it saves the infected file as {original file name of infected}xcod.scr. It then deletes the original copy of the infected file. Infected files are detected as PE_QUERVAR.A.

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

9.158.01

FIRST VSAPI PATTERN DATE:

01 Jun 2012

VSAPI OPR PATTERN File:

9.158.01

VSAPI OPR PATTERN Date:

01 Jun 2012

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

Remove malware/grayware files dropped/downloaded by PE_QUERVAR.A-O

Step 3

Scan your computer with your Trend Micro product and note files detected as PE_QUERVAR.A-O

Step 4

Search and delete the file detected as PE_QUERVAR.A-O

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden files in the search result.

Step 5

Scan your computer with your Trend Micro product to delete files detected as PE_QUERVAR.A-O. 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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