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TROJ_FAM_00001e3.TOMA

May 04, 2013
 Analysis by: Michael Cabel
 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW


This Trojan may allow unauthorized calls using RAS (Remote Access Service) on the affected machine. It may also set the affected machine to automatically dial certain numbers.

This Trojan may be dropped by other malware.

It modifies the Internet Explorer Zone Settings.

However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size:

101,376 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

11 Jun 2010

Payload:

Modifies HOSTS file, Connects to URLs/IPs

Arrival Details

This Trojan may be dropped by the following malware:

  • TROJ_DROPPR.TC

Installation

This Trojan drops the following copies of itself into the affected system:

  • %System%\{random file name}.exe

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

Autostart Technique

This Trojan adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\Run
{random} = "%System%\{random file name}.exe"

Web Browser Home Page and Search Page Modification

This Trojan modifies the Internet Explorer Zone Settings.

HOSTS File Modification

This Trojan adds the following strings to the Windows HOSTS file:

  • 127.0.0.1 {BLOCKED}atebay.org
  • 127.0.0.1 www.{BLOCKED}atebay.org
  • 127.0.0.1 {BLOCKED}va.org
  • 127.0.0.1 www.{BLOCKED}va.org
  • 127.0.0.1 {BLOCKED}m.mininova.org
  • 127.0.0.1 blog.{BLOCKED}va.org
  • 127.0.0.1 {BLOCKED}y.org
  • 127.0.0.1 www.{BLOCKED}y.org

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://{BLOCKED}ut4.cn/update/utu.dat

However, as of this writing, the said sites are inaccessible.

NOTES:
This Trojan may allow unauthorized calls using RAS (Remote Access Service) on the affected machine. It may also set the affected machine to automatically dial certain numbers.

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

7.233.80

FIRST VSAPI PATTERN DATE:

11 Jun 2010

VSAPI OPR PATTERN File:

7.235.00

VSAPI OPR PATTERN Date:

11 Jun 2010

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

Remove the malware/grayware file dropped/downloaded by TROJ_FAM_00001e3.TOMA

Step 3

Identify and terminate files detected as TROJ_FAM_00001e3.TOMA

[ Learn More ]
  1. For Windows 98 and ME users, Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the grayware/spyware file. You may download the said tool here.
  2. 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.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 4

Delete this registry value

[ 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.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\Explorer\Run
    • {random} = "%System%\{random file name}.exe"

Step 5

Remove these strings added by the malware/grayware/spyware in the HOSTS file

[ Learn More ]
    • 127.0.0.1 {BLOCKED}atebay.org
    • 127.0.0.1 http://www.{BLOCKED}atebay.org
    • 127.0.0.1 www.{BLOCKED}atebay.org
    • 127.0.0.1 {BLOCKED}va.org
    • 127.0.0.1 http://www.{BLOCKED}va.org
    • 127.0.0.1 www.{BLOCKED}va.org
    • 127.0.0.1 {BLOCKED}m.mininova.org
    • 127.0.0.1 blog.mininova.org
    • 127.0.0.1 {BLOCKED}y.org
    • 127.0.0.1 http://www.{BLOCKED}y.org
    • www.{BLOCKED}y.org
    • http://www.{BLOCKED}y.org
    • www.{BLOCKED}y.org
"

Step 6

Reset Internet security settings

[ Learn More ]

Step 7

Scan your computer with your Trend Micro product to delete files detected as TROJ_FAM_00001e3.TOMA. 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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