Analysis by: jasperm
 PLATFORM:

Windows 2000, XP, Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This Trojan may be dropped by other malware. It may be unknowingly downloaded by a user while visiting malicious websites.

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

  TECHNICAL DETAILS

File Size: 205,312 bytes
File Type: PE
Memory Resident: No
Initial Samples Received Date: 14 Oct 2010
Payload: Downloads files

Arrival Details

This Trojan may be dropped by other malware.

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

Other System Modifications

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Windows
LoadAppInit_DLLs = 1

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Windows
RequireSignedAppInit_DLLs = 0

Download Routine

This Trojan accesses the following websites to download files:

  • http://{BLOCKED}w.net/imagens/ecko.txt
  • http://{BLOCKED}.{BLOCKED}.244.233/images/ecko.txt
  • http://{BLOCKED}r.net/txt/logs/ecko/ecko.txt
  • http://{BLOCKED}x.net/xxxxerrorxxxx/imagens/ecko/ecko_32.jpg
  • http://{BLOCKED}x.net/error/ecko/ntfy/notify.php

It saves the files it downloads using the following names:

  • %System%\gter.dll - detected as TROJ_GIKU.AX

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)

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

Other Details

This Trojan does the following:

  • It modifies the following registry entry to enable the automatic execution of the downloaded file:
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Windows
  • AppInit_DLLs = "gter.dll"
  • Default is "".

  SOLUTION

Minimum Scan Engine: 8.900
VSAPI PATTERN File: 07.536.17
VSAPI PATTERN Date: 14 Oct 2010
VSAPI PATTERN Date: 10/14/2010 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

Remove malware files dropped/downloaded by TROJ_GIKU.AA

    TROJ_GIKU.AX

Step 3

Restart in Safe Mode

[ Learn More ]

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 NT\CurrentVersion\Windows
    • LoadAppInit_DLLs = 1
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Windows
    • RequireSignedAppInit_DLLs = 0

Step 5

Restore this modified 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 NT\CurrentVersion\Windows
    • From: AppInit_DLLs = gter.dll
      To: AppInit_DLLs =

Step 6

Scan your computer with your Trend Micro product to delete files detected as TROJ_GIKU.AA. 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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