Analysis by: Mar Philip Elaurza
ALIASES:

Backdoor:MSIL/Bladabindi.G (Microsoft)

 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

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 connects to a website to send and receive information. However, as of this writing, the said sites are inaccessible.

It modifies the Internet Explorer Zone Settings.

  TECHNICAL DETAILS

File Size: 285,406 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 31 Mar 2016
Payload: Connects to URLs/IPs, Deletes files

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 adds the following folders:

  • %User Temp%\ns{random}.tmp
  • %User Temp%\domain

(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 drops the following copies of itself into the affected system and executes them:

  • %User Temp%\domain\wdacl.exe
  • %Application Data%\spoolsc.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.. %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming 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 drops the following files:

  • %User Temp%\ns{random}.tmp\marshmallow.dll
  • %User Temp%\arrow.gif
  • %User Temp%\74_453286.png
  • %User Temp%\global.js
  • %User Temp%\fluke lower.jpg
  • %User Temp%\banannanananejakl1
  • %User Temp%\container.html
  • %User Temp%\tag
  • %User Temp%\449bb7442d3adb6f70f6c7bcde488946.cf.jpg
  • %User Temp%\homepage_poptop_getcovered.gif

(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 terminates the execution of the copy it initially executed and executes the copy it drops instead.

Autostart Technique

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

HKCU\Software\Microsoft\
Windows\CurrentVersion\RunOnce
spoolsc = '%Application Data%\spoolsc.exe'

Other System Modifications

This backdoor deletes the following files:

  • created %Application Data%\ns{random}.tmp\marshmallows.dll

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming 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 deletes the following folders:

  • created %Application Data%\ns{random}.tmp

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming 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.)

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
  • Unistall itself
  • Update itself
  • Terminate itself

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

  • http:\metro.{BLOCKED}k.net

However, as of this writing, the said sites are inaccessible.

Web Browser Home Page and Search Page Modification

This backdoor modifies the Internet Explorer Zone Settings.

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 12.436.04
FIRST VSAPI PATTERN DATE: 30 Mar 2016
VSAPI OPR PATTERN File: 12.437.00
VSAPI OPR PATTERN Date: 31 Mar 2016

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

Restart in Safe Mode

[ Learn More ]

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\RunOnce
    • spoolsc = '%Application Data%\spoolsc.exe'

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%\domain\wdacl.exe
  • %Application Data%\spoolsc.exe
  • %User Temp%\arrow.gif
  • %User Temp%\74_453286.png
  • %User Temp%\global.js
  • %User Temp%\fluke lower.jpg
  • %User Temp%\banannanananejakl1
  • %User Temp%\container.html
  • %User Temp%\tag
  • %User Temp%\449bb7442d3adb6f70f6c7bcde488946.cf.jpg
  • %User Temp%\homepage_poptop_getcovered.gif

Step 6

Search and delete this folder

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %User Temp%\domain

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_BLADABINDI.XZH. 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.

Step 8

Reset Internet security settings

[ Learn More ]


Did this description help? Tell us how we did.