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Backdoor.Win32.BANDOK.A

October 16, 2019
 ALIASES:

Trojan:Win32/Skeeyah.A!MTB (Microsoft); HEUR:Trojan.Win32.Agentb.gen (Kaspersky); Mal/Generic-L (Sophos); Win32.Malware!Drop (Sunbelt)

 PLATFORM:

Windows

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • 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.

  TECHNICAL DETAILS

File Size:

1,734,368 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

16 Oct 2019

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 processes:

  • %Program Files%\Internet Explorer\iexplore.exe

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000(32-bit), Server 2003(32-bit), XP, Vista(64-bit), 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit) , or C:\Program Files (x86) in Windows XP(64-bit), Vista(64-bit), 7(64-bit), 8(64-bit), 8.1(64-bit), 2008(64-bit), 2012(64-bit) and 10(64-bit).)

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
vdscl = "%Application Data%\vdscl\vdscl.exe"

Other System Modifications

This Backdoor adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion
1436 = "{random characters}"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion
2940 = "{random characters}"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion
2904 = "{random characters}"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion
2832 = "{random characters}"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion
1312 = "{random characters}"

HKEY_CURRENT_USER\Software
U7292SAJ = "24423"

HKEY_CURRENT_USER\Software
NChswww2 = "17/6/2019"

Other Details

This Backdoor connects to the following possibly malicious URL:

  • http://{BLOCKED}ud.net

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.850

Step 1

Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 users must disable System Restore to allow full scanning of their computers.

Step 2

Restart in Safe Mode

[ Learn More ]

Step 3

Identify and terminate files detected as Backdoor.Win32.BANDOK.A

[ 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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • vdscl = "%Application Data%\vdscl\vdscl.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion
    • 1436 = "{random characters}"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion
    • 2940 = "{random characters}"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion
    • 2904 = "{random characters}"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion
    • 2832 = "{random characters}"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion
    • 1312 = "{random characters}"
  • In HKEY_CURRENT_USER\Software
    • U7292SAJ = "24423"
  • In HKEY_CURRENT_USER\Software
    • NChswww2 = "17/6/2019"

Step 5

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Backdoor.Win32.BANDOK.A. 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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