BKDR_DEEPAND.AA

July 30, 2015
 Analysis by: Francis Xavier Antazo
 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet, Dropped by other malware

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

It runs certain commands that it receives remotely from a malicious user. Doing this puts the affected computer and information found on the computer at greater risk.

It retrieves specific information from the affected system.

  TECHNICAL DETAILS

File Size:

116,016 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

14 Sep 2014

Payload:

Collects system information

Arrival Details

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

  • %System%\msaudnte.dat

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

It drops and executes the following files:

  • %System%\Drivers\{AE2A3887-A30A-4B39-A5E6-AC891A07AFF3}.sys -> to be detected as RTKT_DEEPAND.AA

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

It adds the following processes:

  • regsvr32.exe {loads %System%\msaudnte.dat}

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

Autostart Technique

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

HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\{AE2A3887-A30A-4B39-A5E6-AC891A07AFF3}
ImagePath = "%System%\Drivers\{AE2A3887-A30A-4B39-A5E6-AC891A07AFF3}.sys"

HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\wuauserv
ServiceDll = "%System%\msaudnte.dat"

Other System Modifications

This Trojan adds the following registry entries:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\wuauserv
{default} = "2"

HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\wuauserv
(Default) = "LocalSystem"

HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\wuauserv
Security = (hex values)

HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\{AE2A3887-A30A-4B39-A5E6-AC891A07AFF3}
Type = "1"

HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\{AE2A3887-A30A-4B39-A5E6-AC891A07AFF3}
ErrorControl = "0"

HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\{AE2A3887-A30A-4B39-A5E6-AC891A07AFF3}
Start = "1"

Backdoor Routine

This Trojan executes the following command(s) from a remote malicious user:

  • List Drive and Description
  • List Directory Contents
  • Send Outlook Username and Password
  • Reverse Shell
  • Download Files
  • List and Terminate Processes
  • Run Arbitrary Files

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

  • vpn.{BLOCKED}tionssl.com:443
  • openssh.{BLOCKED}r.com:53

Information Theft

This Trojan retrieves the following information from the affected system:

  • Computer Name
  • OS Version
  • User Name

  SOLUTION

Minimum Scan Engine:

9.750

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.

RESTORE
  • Close Registry Editor.

    • 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. DATA_GENERIC
  • In the Look In drop-down list, select My Computer then press Enter.
  • Once located, select the file then press SHIFT+DELETE to delete it.
    *Note: The file name input box title varies depending on the Windows version (e.g. Search for files or folders named or All or part of the file name.).

    • • For Windows Vista, Windows 7, Windows Server 2008, Windows 8, Windows 8.1, and Windows Server 2012:

    1. Open a Windows Explorer window.
      • For Windows Vista, 7, and Server 2008 users, click Start>Computer.
      • For Windows 8, 8.1, and Server 2012 users, right-click on the lower left corner of the screen, then click File Explorer.
    2. In the Search Computer/This PC input box, type:
      DATA_GENERIC
    3. Once located, select the file then press SHIFT+DELETE to delete it.
      *Note: Read the following Microsoft page if these steps do not work on Windows 7.

    Step 6

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