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TROJ_AGENT.AVTN

May 08, 2013
 ALIASES:

PWS-Axespec.a (McAfee); Downloader (Symantec); Packed.Win32.Katusha.o (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Trojan horse Agent2.AYRN (AVG)

 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 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:

840,704 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

08 May 2013

Arrival Details

This Trojan 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 Trojan creates the following folders:

  • %User Profile%\Microsoft\OFFICE
  • %User Profile%\OFFICE\TEMP
  • %User Profile%\Application Data\VMware

(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.)

Other System Modifications

This Trojan deletes the following files:

  • %Windows%\SoftwareDistribution\DataStore\Logs\edbtmp.log

(Note: %Windows% is the Windows folder, which is usually C:\Windows.)

It adds the following registry keys:

HKEY_LOCAL_MACHINE\Software\Microsoft\
DirectX\MSA

HKEY_LOCAL_MACHINE\Software\Microsoft\
DirectX\MSB

Dropping Routine

This Trojan drops the following files:

  • %System%\svrwsc.exe

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://{BLOCKED}ng.ru/music/forum/index1.php

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.300

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

Delete this registry key

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\Software\Microsoft\DirectX
    • MSA
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\DirectX
    • MSB

Step 3

Search and delete this file

[ Learn More ]
There may be some 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.
  • %System%\svrwsc.exe

Step 4

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%\Microsoft\OFFICE
  • %User Profile%\OFFICE\TEMP
  • %User Profile%\Application Data\VMware

Step 5

Scan your computer with your Trend Micro product to delete files detected as TROJ_AGENT.AVTN. 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.

Step 6

Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.

  • %Windows%\SoftwareDistribution\DataStore\Logs\edbtmp.log


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