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BKDR_REMOSH.JD

May 31, 2017
 Analysis by: Johnlery Triunfante
 ALIASES:

Backdoor.Win32.Agent.dpdb (KASPERSKY); Mal/Emogen-Y (SOPHOS_LITE)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 REPORTED INFECTION:

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

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 may be injected into processes running in memory.

It listens on ports.

  TECHNICAL DETAILS

File Size:

83,968 bytes

File Type:

DLL

Memory Resident:

Yes

Initial Samples Received Date:

26 May 2017

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 may be injected into processes running in memory.

Autostart Technique

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

HKCU\Software\Microsoft\
Windows\CurrentVersion\Run
ctfmon = rundll32.exe "{malware path}",IJA {value}

HKLM\SYSTEM\CurrentControlSet\
Services\{Malware service name}\Parameters
ServiceDll = {Malware path}

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{Malware service name}
ImagePath = "%SystemRoot%\System32\svchost.exe -k netsvcs"

Backdoor Routine

This Backdoor listens on the following port(s):

  • Port 5910

Other Details

This Backdoor does the following:

  • It adds its service name in the following registry value to loads itself on startup by svchost.exe:
    key: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\ Windows NT\CurrentVersion\Svchost
    value: netsvcs
  • It executes the command "systeminfo" to gather system information. It then saves the gathered information and sends it to its remote user.
  • It is capable of receiving and executing shell commands on the affected system.
  • It terminates itself when it receives the "exit" command.

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

13.430.03

FIRST VSAPI PATTERN DATE:

26 May 2017

VSAPI OPR PATTERN File:

13.431.00

VSAPI OPR PATTERN Date:

27 May 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

Restart in Safe Mode

[ Learn More ]

Step 3

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
    • ctfmon = rundll32.exe "{malware path}",IJA {value}

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.

 
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
    • {Malware service name}

Step 5

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