WORM_SMALL.ECD

October 09, 2012
 Analysis by: Kathleen Notario
 ALIASES:

Downloader (Symantec); Backdoor:Win32/Hupigon.EX (Microsoft); PAK:PE_Patch (Kaspersky); Generic BackDoor!dlk (Mcafee); W32/BackDoor.DLK!tr (Fortinet)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Propagates via software vulnerabilities

This worm connects to a random IP address and takes advantage of the vulnerability MS08-067 (Vulnerability in Server Service Could Allow Remote Code Execution). It may also exploit a vulnerability in Microsoft Jet Database Engine (MS08-28) by connecting to port 1433 using certain user names and passwords.

If the exploit is successful, it invokes a shellcode to download and execute files from an FTP server.

This worm may be downloaded by other malware/grayware/spyware from remote sites. It may be dropped by other malware. It may be unknowingly downloaded by a user while visiting malicious websites.

  TECHNICAL DETAILS

File Size:

92,160 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

30 Aug 2011

Payload:

Downloads files, Connects to URLs/IPs

Arrival Details

This worm may be downloaded by other malware/grayware/spyware from remote sites.

It may be dropped by other malware.

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

Installation

This worm drops the following files:

  • %System Root%\Tcpz-x86.sys

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

NOTES:

Download Routine

It connects to a random IP address and takes advantage of the vulnerability MS08-067 (Vulnerability in Server Service Could Allow Remote Code Execution). It may also exploit a vulnerability in Microsoft Jet Database Engine (MS08-28) by connecting to port 1433 using the following user names and passwords:

  • sa
  • ic
  • zxm1987
  • as
  • sql
  • 123456
  • hjs
  • pos
  • anypass
  • sasa
  • kingdee
  • 8888

For more information on the aforementioned vulnerabilities, please see the following pages:

If the exploit is successful, it invokes a shellcode to download and execute files from an FTP server:

  • to.{BLOCKED}a.com

Currently, Trend Micro detects the downloaded files as:

  • BKDR_VENIK.AE
  • BKDR_RBOT.SMB

As a result, the malicious routines of the said files are also exhibited in the system.

It registers its component as a service by creating the following registry:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpz-x86
ImagePath = "%SystemRoot%\Tcpz-x86.sys"

It connects to the following URL:

  • http://net.{BLOCKED}a.com/it.asp?intTimes={number}

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

8.390.01

FIRST VSAPI PATTERN DATE:

30 Aug 2011

VSAPI OPR PATTERN File:

8.479.00

VSAPI OPR PATTERN Date:

08 Oct 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 WORM_SMALL.ECD

Step 3

Identify and terminate files detected as WORM_SMALL.ECD

[ Learn More ]
  1. 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.
  2. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 4

Restart in Safe Mode, and then 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.



HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Tcpz-x86

Step 5

Search and delete this file

[ Learn More ]
There may be some component files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden files and folders in the search result.
  • %System Root%\Tcpz-x86.sys

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_SMALL.ECD. 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 7

Download and apply these security patches Refrain from using these products until the appropriate patches have been installed. Trend Micro advises users to download critical patches upon release by vendors.


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