Analysis by: Kathleen Notario
 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

Infection Channel: Dropped by other malware

This backdoor may be dropped by other malware.

It executes commands from a remote malicious user, effectively compromising the affected system. It connects to a website to send and receive information.

  TECHNICAL DETAILS

File Size: 75,264 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 27 Mar 2012
Payload: Connects to URLs/IPs

Arrival Details

This backdoor may be dropped by the following malware:

  • TROJ_MDROP.YZ
  • TROJ_PIDIEF.ESB

Installation

This backdoor drops the following files:

  • %User Profile%\Application Data\Microsoft\container.exe - also detected as BKDR_AGENTT.YZ

(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} 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
Adobe Container = "%User Profile%\Application Data\Microsoft\container.exe"

Backdoor Routine

This backdoor executes the following commands from a remote malicious user:

  • Create files
  • Execute files

It connects to the following websites to send and receive information:

  • {BLOCKED}2.{BLOCKED}0.155.206

NOTES:

It may also connect to the following site to inform a remote malicious user of its installation and send user information such as user name, host name, and IP address:

  • {BLOCKED}2.{BLOCKED}0.155.206

  SOLUTION

Minimum Scan Engine: 9.200
FIRST VSAPI PATTERN FILE: 8.882.06
FIRST VSAPI PATTERN DATE: 02 Apr 2012
VSAPI OPR PATTERN File: 8.883.00
VSAPI OPR PATTERN Date: 03 Apr 2012

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/grayware files that dropped/downloaded BKDR_AGENTT.YZ

     
    • TROJ_MDROP.YZ
    • TROJ_PIDIEF.ESB

Step 3

Identify and terminate files detected as BKDR_AGENTT.YZ

[ 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

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
    • Adobe Container = "%User Profile%\Application Data\Microsoft\container.exe"

Step 5

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