ADW_ONESTEP.A

 Analysis by: Michael Cabel

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Adware

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW


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.

  TECHNICAL DETAILS

File Size:

227,297 bytes

File Type:

PE

Memory Resident:

Yes

Initial Samples Received Date:

06 Oct 2007

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.

Installation

This adware drops the following files:

  • %Program Files%\OneStepSearch\home.js
  • %Program Files%\OneStepSearch\onestep.dll
  • %Program Files%\OneStepSearch\onestep.exe
  • %Program Files%\OneStepSearch\osopt.exe
  • %Program Files%\OneStepSearch\readme.html
  • %Program Files%\OneStepSearch\uninstall.exe
  • %Program Files%\Mozilla Firefox\searchplugins\onestep.xml

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files.)

It creates the following folders:

  • %Program Files%\OneStepSearch

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files.)

Other System Modifications

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

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\SearchScopes

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\SearchScopes

HKEY_LOCAL_MACHINE\SOFTWARE\OneStepSearch

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
OneStepSearch

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Enum\Root\LEGACY_ONESTEP_SEARCH_SERVICE

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\OneStep Search Service

NOTES:

It terminates the execution of the initially executed malware and executes the file it drops.

  SOLUTION

Minimum Scan Engine:

9.200

SSAPI PATTERN File:

0.540.14

SSAPI PATTERN Date:

06 Oct 2007

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 ADW_ONESTEP.A

[ 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\Microsoft\Internet Explorer
    • SearchScopes
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer
    • SearchScopes
  • In HKEY_LOCAL_MACHINE\SOFTWARE
    • OneStepSearch
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall
    • OneStepSearch
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\Root
    • LEGACY_ONESTEP_SEARCH_SERVICE
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
    • OneStep Search Service

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. %Program Files%\OneStepSearch

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. %Program Files%\Mozilla Firefox\searchplugins\onestep.xml

Step 6

Scan your computer with your Trend Micro product to delete files detected as ADW_ONESTEP.A. 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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