OSX_YONTOO.A

March 29, 2013
 Analysis by: Rhena Inocencio
 ALIASES:

Trojan.OSX.Yontoo.a (Kaspersky), OSX/Yontoo-B (Sophos)

 PLATFORM:

Mac OS X

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

  • Threat Type: Adware

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This adware may be downloaded by other malware/grayware/spyware from remote sites. It may be manually installed by a user.

  TECHNICAL DETAILS

Payload:

Downloads files

Arrival Details

This adware may be downloaded by other malware/grayware/spyware from remote sites.

It may be manually installed by a user.

Installation

This adware drops the following files:

  • ~/Library/Safari/Extensions/torrenthandler.safariextz
  • ~/Library/Safari/Extensions/Yontoo.safariextz

Download Routine

This adware accesses the following websites to download files:

  • http://{BLOCKED}ine-hd.tv/fttmac.zip - Yontoo Installer Silent

NOTES:

The following windows appear upon installation:

It installs the Yontoo extension in the following browsers:

  • Firefox
  • Safari
  • Chrome

  SOLUTION

Minimum Scan Engine:

9.300

FIRST VSAPI PATTERN FILE:

9.808.03

FIRST VSAPI PATTERN DATE:

21 Feb 2013

VSAPI OPR PATTERN File:

9.809.00

VSAPI OPR PATTERN Date:

22 Feb 2013

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

NOTES:

Before scanning:

  1. Remove the added extension on browsers.
    For Safari:
    • Open a Safari browser.
    • Click Safari Menu > Preferences.
    • Go to Extensions tab.
    • Select the Extension and then click the Uninstall button.

    For Firefox:
    • Open a Firefox browser.
    • Click Tools > Add-ons
    • Go to Extensions panel.
    • Select the Extension and then click the Uninstall or Remove button

    For Chrome:
    • Open a Google Chrome browser.
    • Click Window > Extensions.
    • Select the Extension and then click the Uninstall button or the Trash Can icon
  2. Close all browsers.


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