Threat Encyclopedia

BKDR_IRCBOT.HIK

Publish date: March 17, 2011

ANALYSIS BY

Sabrina Lei Sioting


ALIASES:

Backdoor:Win32/Momibot.gen!B (Microsoft); PWS-Zbot.gen.do (McAfee); Troj/FakeAV-CWA (Sophos)

PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type:Backdoor

  • Destructiveness:No

  • Encrypted: No

  • In the wild: Yes

OVERVIEW


This backdoor uses social engineering methods to lure users into performing certain actions that may, directly or indirectly, cause malicious routines to be performed. Specifically, it arrives as a dating spam attachment that bears the .SCR extension.

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

This backdoor arrives as an attachment to email messages spammed by other malware/grayware or malicious users.

TECHNICAL DETAILS

Ports:

TCP port 6667 (IRCU)

File Size:

62,088 bytes

File Type:

PE

File Compression:

UPX

Memory Resident:

No

Initial Samples Received Date:

16 Mar 2011

Arrival Details

This backdoor arrives as an attachment to email messages spammed by other malware/grayware or malicious users.

Installation

This backdoor drops the following copies of itself into the affected system:

  • %System%\{random name of a file found in this folder}{random letter}.exe

(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 drops the following files:

  • %System%\1477908159.dat - non-malicious file

(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 adds the following mutexes to ensure that only one of its copies runs at any one time:

  • 9LZZ1TXjZ5NHrnf71f

Autostart Technique

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

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Run
Win32Update = "{random name of a file found in the Windows system folder}{random letter}.exe"

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\RunServices
Win32Update = "{random name of a file found in the Windows system folder}{random letter}.exe"

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\RunServices
Win32Update = "{random name of a file found in the Windows system folder}{random letter}.exe"

HKEY_LOCAL_MACHINE\Software\Microsoft\
OLE
Win32Update = "{random name of a file found in the Windows system folder}{random letter}.exe"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Lsa
Win32Update = "{random name of a file found in the Windows system folder}{random letter}.exe"

Backdoor Routine

This backdoor opens the following port(s) where it listens for remote commands:

  • TCP port 6667

It connects to any of the following IRC server(s):

  • #AllNiteCafe

It connects to the following URL(s) to send and receive commands from a remote malicious user:

  • {BLOCKED}.{BLOCKED}.135.174

NOTES:

It can possibly execute the following command(s) from a remote malicious user:

  • Download and execute an updated copy of itself or other malware
  • Gather system information
  • Start and stop services

SOLUTION

Minimum Scan Engine:

8.900

VSAPI OPR PATTERN File:

7.907.00

VSAPI OPR PATTERN Date:

16 Mar 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

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\CurrentVersion\Run
    • Win32Update = {random name of a file found in the Windows system folder}{random letter}.exe
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunServices
    • Win32Update = {random name of a file found in the Windows system folder}{random letter}.exe
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunService
    • Win32Update = {random name of a file found in the Windows system folder}{random letter}.exe
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\OLE
    • Win32Update = {random name of a file found in the Windows system folder}{random letter}.exe
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa
    • Win32Update = {random name of a file found in the Windows system folder}{random letter}.exe

Step 3

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%\1477908159.dat

Step 4

Scan your computer with your Trend Micro product to delete files detected as BKDR_IRCBOT.HIK. 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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