Analysis by: Kathleen Notario
 PLATFORM:

Windows 98, ME, NT, 2000, XP, Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Trend Micro has flagged this Symbian as noteworthy due to the increased potential for damage, propagation, or both, that it possesses.

To get a one-glance comprehensive view of the behavior of this Trojan, refer to the Threat Diagram shown below.

This is a Symbian S60 malware that drops the following malicious file to automatically send Short Message Service (SMS) message:

!:\System\Apps\ZverOK\default.py -TROJ_FLOCK.I

It runs on Symbian S60.

This Trojan may be unknowingly downloaded by a user while visiting malicious websites. It may be manually installed by a user.

  TECHNICAL DETAILS

File Size: 330,167 bytes
File Type: SIS
Memory Resident: Yes
Initial Samples Received Date: 26 Jun 2010
Payload: Drops files

Arrival Details

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

It may be manually installed by a user.

Installation

This Trojan drops the following non-malicious files:

  • !:\System\Apps\ZverOK\about.txt
  • !:\System\Apps\ZverOK\ZverOK.aif
  • !:\System\Apps\ZverOK\ZverOK.app
  • !:\System\Apps\ZverOK\ZverOK.rsc
  • !:\System\Apps\ZverOK\ZverOK_caption.rsc
  • !:\System\Data\appuifwmodule.rsc
  • !:\System\libs\_messaging.pyd
  • !:\System\libs\APPSWITCH.PYD
  • !:\System\libs\appuifw.py
  • !:\System\libs\appuifw.py
  • !:\System\libs\inbox.pyd
  • !:\System\libs\KEYPRESS.PYD
  • !:\System\libs\LANGSWITCH.PYD
  • !:\System\libs\messaging.py
  • !:\System\libs\python_appui.dll
  • !:\System\libs\python222.dll
  • !:\System\libs\random.py
  • !:\System\programs\python_launcher.exe

Dropping Routine

This Trojan drops the following files:

  • !:\System\Apps\ZverOK\default.py - detected as TROJ_FLOCK.I

Other Details

This Trojan runs on the following platforms:

  • Symbian Series 60

  SOLUTION

Minimum Scan Engine: 8.900
VSAPI OPR PATTERN File: 7.269.00
VSAPI OPR PATTERN Date: 27 Jun 2010

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 SYMBOS_FLOCK.I

Step 3

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