Analysis by: Joselyn Canuela

 ALIASES:

Backdoor:MSIL/Bladabindi (Microsoft), Backdoor.MSIL.Agent.igo (Kaspersky), Backdoor.Ratenjay (Norton)

 PLATFORM:

Windows

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: No

  • 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 logs a user's keystrokes to steal information.

It connects to certain websites to send and receive information.

  TECHNICAL DETAILS

File Size: 24,064 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 17 Feb 2015
Payload: Connects to URLs/IPs, Compromises network security, Logs keystrokes

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 and executes them:

  • %User Temp%\IDM.EXE

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

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

  • 97466d0d68ada90b16f12a92debf8c8b

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
97466d0d68ada90b16f12a92debf8c8b = "%User Temp%\IDM.EXE"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
97466d0d68ada90b16f12a92debf8c8b = "%User Temp%\IDM.EXE"

It drops the following file(s) in the Windows User Startup folder to enable its automatic execution at every system startup:

  • %User Startup%\97466d0d68ada90b16f12a92debf8c8b.exe

(Note: %User Startup% is the current user's Startup folder, which is usually C:\Documents and Settings\{user}\Start Menu\Programs\Startup on Windows 2000 and XP, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows Vista, 7, and 8.)

Other System Modifications

This Backdoor adds the following registry entries as part of its installation routine:

HKEY_CURRENT_USER\Environment
SEE_MASK_NOZONECHECKS = "1"

HKEY_CURRENT_USER\Software\97466d0d68ada90b16f12a92debf8c8b
{string} = ""
where {string} can be any of the following:

  • ll
  • kl
  • prof
  • rn

Backdoor Routine

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

  • Download and Execute files
  • Compress files for uploading
  • Load plugins
  • Ping
  • Registry Management
  • Remote Shell Execution
  • Restart
  • Screenshot
  • Uninstall Itself
  • Update Itself
  • Terminate Itself

Information Theft

This Backdoor logs a user's keystrokes to steal information.

Other Details

This Backdoor connects to the following website to send and receive information:

  • {BLOCKED}ok-update.{BLOCKED}uake.com

It does the following:

  • It executes the following command to bypass Windows Firewall:
    • netsh firewall add allowedprogram "%User Temp%\IDM.EXE" "IDM.EXE" ENABLE
  • It saves the stolen information in the created registry:
    • HKEY_CURRENT_USER\Software\97466d0d68ada90b16f12a92debf8c8b

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 11.485.50
FIRST VSAPI PATTERN DATE: 17 Feb 2015
VSAPI OPR PATTERN File: 11.486.00
VSAPI OPR PATTERN Date: 18 Feb 2015

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 3

Identify and terminate files detected as BKDR_BLADABI.SMC

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. 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.
  3. 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_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
    • 97466d0d68ada90b16f12a92debf8c8b = "%User Temp%\IDM.EXE"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • 97466d0d68ada90b16f12a92debf8c8b = "%User Temp%\IDM.EXE"
  • In HKEY_CURRENT_USER\Software
    • 97466d0d68ada90b16f12a92debf8c8b
  • In HKEY_CURRENT_USER\Environment
    • SEE_MASK_NOZONECHECKS = "1"

Step 5

Search and delete this file

[ Learn More ]
There may be some 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%\IDM.EXE
  • %User Startup%\97466d0d68ada90b16f12a92debf8c8b.exe

Step 6

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