TROJ_DLOADR.DFK

October 08, 2012
 Analysis by: jasperm
 ALIASES:

Kaspersky: Trojan-Dropper.Win32.Stabs.iet ; Sophos: Mal/Agent-NA

 PLATFORM:

Windows 2000, XP, Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

It adds strings to the Windows HOSTS file.

This Trojan may be dropped by other malware. It may be unknowingly downloaded by a user while visiting malicious websites. However, as of this writing, the said sites are inaccessible.

It executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

  TECHNICAL DETAILS

File Size:

88,110 bytes

File Type:

PE

Memory Resident:

No

Initial Samples Received Date:

02 Dec 2010

Payload:

Modifies HOSTS file, Downloads files

Arrival Details

This Trojan may be dropped by other malware.

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

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

Download Routine

This Trojan accesses the following websites to download files:

  • http://{BLOCKED}.{BLOCKED}.215.92/~loguin/arquivos/Navegador_WAP.exe

It saves the files it downloads using the following names:

  • %Windows%\ltisv32.exe

(Note: %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.)

It then executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

HOSTS File Modification

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

  • 127.0.0.1 www.{BLOCKED}livros.net
  • 127.0.0.1 www.{BLOCKED}uca.net
  • 127.0.0.1 {BLOCKED}gado.net
  • 127.0.0.1 www.{BLOCKED}gado.net

  SOLUTION

Minimum Scan Engine:

8.900

VSAPI PATTERN File:

7.685.80

VSAPI PATTERN Date:

02 Dec 2010

VSAPI PATTERN Date:

12/2/2010 12:00:00 AM

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

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

Step 3

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

[ Learn More ]
    • 127.0.0.1 www.{BLOCKED}livros.net
    • 127.0.0.1 www.{BLOCKED}uca.net
    • 127.0.0.1 {BLOCKED}gado.net
    • 127.0.0.1 www.{BLOCKED}gado.net
"


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