Analysis by: Michael Cabel

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet, Dropped by other malware

This backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It executes commands from a remote malicious user, effectively compromising the affected system.

It performs denial of service (DoS) attacks on affected systems using specific flooding method(s).

  TECHNICAL DETAILS

File Size: 131,072 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 07 Nov 2012
Payload: Connects to URLs/IPs, Compromises system security

Arrival Details

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

  • %Application Data%\Microsoft\svchost.exe

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Windows\Profiles\{user name}\Application Data on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Application Data on Windows NT, and C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003.)

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
svchost.exe = "%Application Data%\Microsoft\svchost.exe"

Backdoor Routine

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

  • TCP port 443

It executes the following commands from a remote malicious user:

  • Download File
  • Start/Stop Flooding
  • Update itself
  • Uninstall Itself
  • Display message box
  • Make itself idle
  • Execute files
  • Steal Mozilla Firefox passwords
  • Send application privileges
  • Show DNS

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

  • {BLOCKED}.{BLOCKED}.185.21

Denial of Service (DoS) Attack

This backdoor performs denial of service (DoS) attacks on affected systems using the following flooding method(s):

  • UDP Flood
  • SYN Flood

NOTES:

It sends the following system information to the remote malicious user:

  • Computer name
  • Operating System Version
  • Processor type and speed
  • User name

  SOLUTION

Minimum Scan Engine: 9.300

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

Terminate a malware/grayware process

[ Learn More ]

*Note: If the detected process is not displayed in theWindows Task Manager, continue doing the next steps.

    %Application Data%\Microsoft\svchost.exe

Step 3

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
    • svchost.exe = "%Application Data%\Microsoft\svchost.exe"

Step 4

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