TROJ_RECAL.BB

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: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • 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.

It executes the dropped file(s). As a result, malicious routines of the dropped files are exhibited on the affected system.

It deletes itself after execution.

  TECHNICAL DETAILS

File Size:

330,752 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

21 Mar 2012

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 drops the following copies of itself into the affected system:

  • %System Root%\RECYCLER\doc.xls

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

It drops the following files:

  • %System Root%\RECYCLER\Game.swf
  • {malware path}\exe.com).xls
  • %System Root%\ProgramData\Microsoft\Windows\Common\QQlive.exe

It creates the following folders:

  • %System Root%\ProgramData\Microsoft\Windows\Common

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

Dropping Routine

This Trojan drops the following files:

  • %System Root%\ProgramData\Microsoft\Windows\Common\Utility.dll - detected as BKDR_DERVEC.AB
  • %System Root%\ProgramData\Microsoft\Windows\NetCC457.dll - detected as BKDR_DERVEC.AB

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

It executes the dropped file(s). As a result, malicious routines of the dropped files are exhibited on the affected system.

Other Details

This Trojan deletes itself after execution.

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

8.854.05

FIRST VSAPI PATTERN DATE:

21 Mar 2012

VSAPI OPR PATTERN File:

8.855.00

VSAPI OPR PATTERN Date:

22 Mar 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 files dropped/downloaded by TROJ_RECAL.BB

     BKDR_DERVEC.AB

Step 3

Identify and terminate files detected as TROJ_RECAL.BB

[ 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 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. %System Root%\ProgramData\Microsoft\Windows\Common

Step 5

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.
%System Root%\RECYCLER\Game.swf
{malware path}\exe.com).xls

Step 6

Scan your computer with your Trend Micro product to delete files detected as TROJ_RECAL.BB. 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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