Analysis by: kathleenno
ALIASES:

Hiloti.gen.w (Mcafee); Mal/Hiloti-D (Sophos); W32/Hiloti.Q!tr (Fortinet); Trojan W32/Hiloti.FYS (Norman)

 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

It resolves an IP address to download an updated copy of itself or another malicious file. The resolved IP address is in the following format:

  • http://{date+data}.{resolved address}.com/get.php

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.

  TECHNICAL DETAILS

File Size: 118,784 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 12 May 2011
Payload: Resolves an IP address

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 filename}.dll - also detected as TROJ_HILOTI.FE
  • %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:

  • %User Profile%\Local Settings\Application Data\{Random CLSID for Firefox}

(Note: %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 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 entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Mozilla\
Firefox\Extensions
{Random CLSID for Firefox} = %User Profile%\Local Settings\Application Data\{Random CLSID for Firefox}\

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

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

NOTES:
It resolves an IP address to download an updated copy of itself or another malicious file. The resolved IP address is in the following format:

  • http://{date+data}.{resolved address}.com/get.php

  SOLUTION

Minimum Scan Engine: 8.900
FIRST VSAPI PATTERN FILE: 8.152.13
FIRST VSAPI PATTERN DATE: 12 May 2011

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 TROJ_HILOTI.FE

     JS_GORD.F

Step 3

Scan your computer with your Trend Micro product and note files detected as TROJ_HILOTI.FE

Step 4

Restart in Safe Mode

[ Learn More ]

Step 5

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • {random} = rundll32.exe {malware path and file name},Startup
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Mozilla\Firefox\Extensions
    • {Random CLSID for Firefox} = %User Profile%\Local Settings\Application Data\{Random CLSID for Firefox}\

Step 6

Delete this registry key

[ 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. Before you could do this, you must restart in Safe Mode. For instructions on how to do this, you may refer to this page If the preceding step requires you to restart in safe mode, you may proceed to edit the system registry.

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

Step 7

Search and delete these folders

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result. %User Profile%\Local Settings\Application Data\{Random CLSID for Firefox}

Step 8

Search and delete the file detected as TROJ_HILOTI.FE

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden files in the search result.

Step 9

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_HILOTI.FE. 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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