TROJ_RENOS.FRS


 ALIASES:

Microsoft: TrojanDownloader:Win32/Renos.NX ; Sophos: Mal/FakeAV-GX ; Sunbelt: Trojan.Win32.Generic!BT

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

This Trojan may be dropped by other malware. It may be unknowingly downloaded by a user while visiting malicious websites. However, as of this writing, the said sites are inaccessible.

It uses Windows Task Scheduler to create a scheduled task that executes the dropped copy.

  TECHNICAL DETAILS

File Size:

Varies

File Type:

PE

Memory Resident:

Yes

Initial Samples Received Date:

23 Dec 2010

Arrival Details

This Trojan may be dropped by other malware.

It may be unknowingly downloaded by a user while visiting malicious websites.

However, as of this writing, the said sites are inaccessible.

Installation

This Trojan drops the following files:

  • %Windows%\Tasks\{62C40AA6-4406-467a-A5A5-DFDF1B559B7A}.job - task file to enable automatic execution of its copy

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

It drops the following copies of itself into the affected system:

  • %Windows%\Cgowua.exe

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

It uses Windows Task Scheduler to create a scheduled task that executes the dropped copy.

Other System Modifications

This Trojan adds the following registry keys as part of its installation routine:

HKEY_CURRENT_USER\Software\H308CABBPI

Download Routine

This Trojan accesses the following websites to download files:

  • http://{BLOCKED}n.com/1wave.php

Other Details

This Trojan connects to the following URL(s) to check for an Internet connection:

  • vkontakte.ru
  • soso.com

  SOLUTION

Minimum Scan Engine:

8.900

VSAPI PATTERN File:

7.721.00

VSAPI PATTERN Date:

23 Dec 2010

VSAPI PATTERN Date:

12/23/2010 12:00:00 AM

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

Identify and terminate files detected as TROJ_RENOS.FRS

[ Learn More ]
  1. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  2. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 3

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. Before you could do this, you must restart in Safe Mode. For instructions on how to do this, you may refer to this page If the preceding step requires you to restart in safe mode, you may proceed to edit the system registry.

 
  • In HKEY_CURRENT_USER\Software
    • H308CABBPI

Step 4

Search and delete this file

[ 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. %Windows%\Tasks\{62C40AA6-4406-467a-A5A5-DFDF1B559B7A}.job

Step 5

Scan your computer with your Trend Micro product to delete files detected as TROJ_RENOS.FRS. 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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