TROJ_HILOTI

 Analysis by: Dianne Lagrimas

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW


This description is based is a compiled analysis of several variants of TROJ_HILOTI. Note that specific data such as file names and registry values may vary for each variant.

This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

As of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size:

Varies

File Type:

PE

Memory Resident:

Yes

Initial Samples Received Date:

07 Feb 2011

Payload:

Downloads files

Arrival Details

This Trojan 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 Trojan drops the following files:

  • %Windows%\{random name}.dll
  • %User Profile%\Local Settings\Application Data\{Random CLSID for Firefox}\chrome.manifest - non-malicious file
  • %User Profile%\Local Settings\Application Data\{Random CLSID for Firefox}\chrome\content\_cfg.js - non-malicious file
  • %User Profile%\Local Settings\Application Data\{Random CLSID for Firefox}\chrome\content\overlay.xul - detected as JS_GORD.F
  • %User Profile%\Local Settings\Application Data\{Random CLSID for Firefox}\install.rdf - non-malicious file

(Note: %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.. %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)

It creates the following folders:

  • %Application Data%\{Random CLSID for Firefox}

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Windows\Profiles\{user name}\Application Data on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Application Data on Windows NT, and C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003.)

It injects itself into the following processes as part of its memory residency routine:

  • explorer.exe

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{random} = "rundll32.exe "{malware path and file name}",Startup"

Other System Modifications

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\{random characters}

Download Routine

This Trojan accesses the following websites to download files:

  • {BLOCKED}db103a.{BLOCKED}ro.net
  • {BLOCKED}7db1000.{BLOCKED}ero.net
  • {BLOCKED}db1000.{BLOCKED}zy.net
  • {date-time}.{BLOCKED}zy.net/get2.php
  • http://{BLOCKED}db0904.meetri.net/get2.php
  • http://{BLOCKED}b0905.gabcat.net/get2.php

As of this writing, the said sites are inaccessible.

NOTES:

This description is based is a compiled analysis of several variants of TROJ_HILOTI. Note that specific data such as file names and registry values may vary for each variant.

  SOLUTION

Minimum Scan Engine:

9.200

Trend customers:

    Keep your pattern and scan engine files updated. Trend Micro antivirus software can clean or remove most types of computer threats. Malware, though, such as Trojans, scripts, overwriting viruses and joke programs which are identified as uncleanable, should simply be deleted.

All Internet users:

    1. Use HouseCall - the Trend Micro online threat scanner to check for malware that may already be on your PC.
    2. Catch malware/grayware before they affect your PC or network. Secure your Web world with Trend Micro products that offer the best anti-threat and content security solutions for home users, corporate users, and ISPs. Go here for more information on Trend Micro products that fit your needs.


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