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BKDR_BADEY.A
Malware type: Backdoor
Destructive: No
Platform: Windows 2000, XP, Server 2003
Encrypted: No
In the wild: Yes

Overview


Trend Micro has flagged this backdoor as noteworthy due to the increased potential for damage, propagation, or both, that it possesses. Specifically, it is being downloaded by the specially crafted script, HTML_BADEY.A, which exploits a vulnerability in Internet Explorer.

To get a one-glance comprehensive view of the behavior of this Backdoor, refer to the Threat Diagram shown below.

This Backdoor may be downloaded from remote sites. It may also be downloaded by HTML_BADEY.A. It drops component files and injects itself into the processes running in the affected system's memory. It registers as a system service to ensure its automatic execution at every system startup by adding registry entries. It opens certain ports.

This Backdoor accesses websites to download files. It saves the files it downloads using certain file names. This backdoor downloads encrypted files, and then decrypts and reads these files, which contain backdoor commands that it executes on the system.

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

Technical Details


Ports used: UDP port 80 (HTTP)
File size: Varies
File type: PE
Memory resident: Yes
Initial samples received date: 04 Nov 2010
Payload: Downloads files

Arrival Details

This backdoor may be downloaded by the following malware/grayware/spyware from remote sites:

  • HTML_BADEY.A

It may be downloaded from the following remote sites:

  • http://www.{BLOCKED}lub.com/reg/linkbl.gif

Installation

This backdoor drops the following component file(s):

  • %System%\msnetacsvc.dll - also detected as BKDR_BADEY.A
  • %User Startup%\ctfmon.exe - also detected as BKDR_BADEY.A

(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.. %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup.)

It injects itself into the following processes running in the affected system's memory:

  • svchost.exe

Autostart Technique

This backdoor registers as a system service to ensure its automatic execution at every system startup by adding the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\NWCWorkstation
DisplayName = NetWare Workstations

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\NWCWorkstation
ObjectName = LocalSystem

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\NWCWorkstation
Type = 0

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\NWCWorkstation
Start = 2

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\NWCWorkstation
ErrorControl = 1

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\NWCWorkstation
ImagePath = %SystemRoot%\System32\svchost.exe -k netsvcs

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\NWCWorkstation
Description = "Provide NetWare network file and print resources visit."

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\NWCWorkstation\Parameters
ServiceDll = "%SystemRoot%\System32\msnetacsvc.dll"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\NWCWorkstation\Security
Security = {hex values}

Backdoor Routine

This backdoor opens the following ports:

  • UDP port 80 (HTTP)

Download Routine

This backdoor accesses the following websites to download files:

  • http://{BLOCKED}8.114.26/images/{random}.gif
  • http://{BLOCKED}8.114.26/pic/{random}.gif
  • http://{BLOCKED}8.114.26/image/{random}.gif
  • http://{BLOCKED}8.114.26/binary/{random}.gif
  • http://{BLOCKED}8.114.26/news/{random}.gif
  • http://{BLOCKED}8.114.26/index/{random}.gif
  • http://{BLOCKED}8.114.26/picture/{random}.gif
  • http://{BLOCKED}8.114.26/bbs/{random}.gif

It saves the files it downloads using the following names:

  • %User temp%\{random file name}.tmp

Other Details

This backdoor does the following:

  • Downloads encrypted files, and then decrypts and reads these files, which contain backdoor commands that it executes on the system.

Solution


Minimum scan engine: 8.900
First VSAPI Pattern File: 7.594.09
First VSAPI Pattern Release Date: 04 Nov 2010
VSAPI OPR Pattern Version: 7.595.00
VSAPI OPR Pattern Release Date: 04 Nov 2010

Step 1

For Windows ME and XP 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 BKDR_BADEY.A

Step 3

Restart in Safe Mode

[ Learn more ]

Step 4

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.


 
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
    • NWCWorkstation

Step 5

Search and delete these files

[ 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.
  • %User temp%\{random fine name}.tmp

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_BADEY.A 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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Analysis By: Roland Dela Paz

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