BREX_SENSAVE.WF

March 28, 2014
 Analysis by: Rika Joi Gregorio
 Modified by: Adrian Cofreros
 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

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

  • Threat Type: Adware

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Dropped by other malware, Downloaded from the Internet

This adware arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites. It may be dropped by other malware.

It does not have any propagation routine.

It does not have any backdoor routine.

  TECHNICAL DETAILS

File Size:

4,173 bytes

File Type:

Other

Initial Samples Received Date:

11 Mar 2014

Payload:

Drops files

Arrival Details

This adware arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It may be dropped by other malware.

Installation

This adware drops the following files:

  • %Application Data%\Mozilla\Firefox\Profiles\{random value}.default\extensions\{2d7886a0-85bb-4bf2-b684-ba92b4b21d23}.xpi
  • %Application Data%\Mozilla\Firefox\Profiles\{random value}.default\healthreport.sqlite
  • %Application Data%\Mozilla\Firefox\Profiles\{random value}.default\addons.json

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)

It creates the following folders:

  • %Application Data%\Mozilla\Firefox\Profiles\{random value}.default\extensions
  • %Application Data%\Mozilla\Firefox\Profiles\{random value}.default\healthreport
  • %Application Data%\Mozilla\Firefox\Profiles\{random value}.default\bookmarks-{year-month-day of installation}_5.json

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)

Propagation

This adware does not have any propagation routine.

Backdoor Routine

This adware does not have any backdoor routine.

NOTES:

This is a browser extension for Mozilla, which is used to load the following URL:

  • http://ff.{BLOCKED}s.com/version.js?appTitle=SaveSense&cb={current month integer}_{current day integer}

It also affects disk cache for Mozilla when it loads the URL.

It does not have rootkit capabilities.

It does not exploit any vulnerability.

  SOLUTION

Minimum Scan Engine:

9.700

FIRST VSAPI PATTERN FILE:

10.676.01

FIRST VSAPI PATTERN DATE:

20 Mar 2014

VSAPI OPR PATTERN File:

10.677.00

VSAPI OPR PATTERN Date:

21 Mar 2014

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

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.  
  • %Application Data%\Mozilla\Firefox\Profiles\{random value}.default\extensions
  • %Application Data%\Mozilla\Firefox\Profiles\{random value}.default\healthreport
  • %Application Data%\Mozilla\Firefox\Profiles\{random value}.default\bookmarks-{year-month-day of installation}_5.json

Step 3

Search and delete these files

[ 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.
  • %Application Data%\Mozilla\Firefox\Profiles\{random value}.default\addons.json
  • %Application Data%\Mozilla\Firefox\Profiles\{random value}.default\healthreport.sqlite

Step 4

Scan your computer with your Trend Micro product to delete files detected as BREX_SENSAVE.WF. 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.

NOTES:

Before proceeding to Step 2, please perform the following steps for Mozilla Firefox users only:

  1. Open Firefox.
  2. Go to Tools > Add-ons.
  3. Select bProtector and click Remove.

Check the disk cache for the temporary Internet file for Mozilla Firefox:

  1. Open Firefox.
  2. Type "about:cache"
  3. Click "List Cache Entries" on Disk cache device
  4. Look for http://ff.{BLOCKED}s.com/version.js


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