BKDR_BLADABINDI.YYSRO

 Analysis by: Michael Jay Villanueva

 ALIASES:

Backdoor:MSIL/Bladabindi (Microsoft)

 PLATFORM:

Windows

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • 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.

  TECHNICAL DETAILS

File Size:

581,632 bytes

File Type:

EXE, Other

Memory Resident:

Yes

Initial Samples Received Date:

26 Oct 2017

Payload:

Drops files, Connects to URLs/IPs, Logs keystrokes, Steals information

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 a copy of itself in the following folders using different file names:

  • %User Profile%\server.exe
  • %User Startup%\4610427f9cc5281defe9550a924fd4ea.exe

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.. %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.)

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:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
4610427f9cc5281defe9550a924fd4ea = “%User Profile%\server.exe”

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
4610427f9cc5281defe9550a924fd4ea = “%User Profile%\server.exe”

Other System Modifications

This Backdoor adds the following registry keys:

HKEY_CURRENT_USER\Software\4610427f9cc5281defe9550a924fd4ea

It adds the following registry entries:

HKEY_CURRENT_USER\Environment
SEE_MASK_NOZONECHECKS = "1"

HKEY_CURRENT_USER\Software\4610427f9cc5281defe9550a924fd4ea
US = "@"

Propagation

This Backdoor drops the following copy of itself in all physical and removable drives:

  • {Drive Letter}\! My Picutre.SCR

Dropping Routine

This Backdoor drops the following files:

  • %User Profile%\server.exe.tmp

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)

Other Details

This Backdoor connects to the following possibly malicious URL:

  • zahora.{BLOCKED}p.biz

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

13.742.03

FIRST VSAPI PATTERN DATE:

26 Oct 2017

VSAPI OPR PATTERN File:

13.743.00

VSAPI OPR PATTERN Date:

27 Oct 2017

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

Terminate a process file/s detected as BKDR_BLADABINDI.YYSRO

[ Learn More ]

*Note: If the detected file/s is/are not displayed in theWindows Task Manager, continue doing the next steps.

Step 4

Delete this registry key

[ 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.

  • HKEY_CURRENT_USER\Software\4610427f9cc5281defe9550a924fd4ea

Step 5

Delete these registry values

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator’s help. You may also check out this Microsoft article first before modifying your computer's registry.

  • In HKEY_CURRENT_USER\Environment
    • SEE_MASK_NOZONECHECKS = “1”
  • In HKEY_CURRENT_USER\Software\4610427f9cc5281defe9550a924fd4ea
    • US = “@”
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • 4610427f9cc5281defe9550a924fd4ea = “%User Profile%\server.exe”
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • 4610427f9cc5281defe9550a924fd4ea = “%User Profile%\server.exe”

Step 6

Search and delete these files

[ 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 Profile%\server.exe.tmp

Step 7

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