Analysis by: Rhena Inocencio
ALIASES:

Trojan:Win32/Dynamer!ac (Microsoft), MSIL/Agent.ABP trojan (ESET)

 PLATFORM:

Windows

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: Yes

  • 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 uses the Windows Task Scheduler to add a scheduled task that executes the copies it drops.

It executes commands from a remote malicious user, effectively compromising the affected system.

It logs a user's keystrokes to steal information.

  TECHNICAL DETAILS

File Size: 560,736 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 19 May 2016
Payload: Connects to URLs/IPs, Terminates processes

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

  • %All Users Profile%\{6 digits}\helper.exe

(Note: %All Users Profile% is the All Users folder, where it usually is C:\Documents and Settings\All Users on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData 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:

  • %Tasks%\Computer Helper - scheduled task
  • %All Users Profile%\{41 characters}

(Note: %All Users Profile% is the All Users folder, where it usually is C:\Documents and Settings\All Users on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData 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 uses the Windows Task Scheduler to add a scheduled task that executes the copies it drops.

It creates the following folders:

  • %All Users Profile%\{6 digits}
  • %All Users Profile%\{6 digits}\{6 digits}

(Note: %All Users Profile% is the All Users folder, where it usually is C:\Documents and Settings\All Users on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData 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.)

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\RunOnce
Computer Helper = "%All Users Profile%\{6 digits}\helper.exe -a /a"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Computer Helper = "%All Users Profile%\{6 digits}\helper.exe -a /a"

Other System Modifications

This backdoor adds the following registry entries:

HKEY_CURRENT_USER\Software
{base64 encoded data} = "{base64 encoded data}"

Backdoor Routine

This backdoor executes the following commands from a remote malicious user:

  • Downloads and executes arbitrary files
  • Downloads and executes custom Crypto Miner
  • Downloads custom password recovery tool
  • Searches for files
  • Performs DDOS
  • Modifies HOSTS file to redirect hosts/URLs
  • Visits arbitrary websites (browser can be hidden and have muted audio)
  • Seeds torrent
  • Updates itself
  • Updates backup C&C
  • Remotes Desktop Control
  • Remotes shell
  • Remotes Script
  • Records audio using system's microphone
  • Controls Webcam
  • Uninstalls itself
  • Executes/Terminates/Disables Task Manager
  • Executes/Terminates/Disables Command Prompt
  • Executes/Terminates/Disables Registry Editor
  • Hides/Shows Taskbar
  • Hides/Shows Desktop
  • Opens/Closes CD-ROM door
  • Turns on/off user's monitor
  • Enables/Disables Keyboard
  • Enables/Disables Mouse
  • Swaps/Resets Mouse
  • Deletes Restore points
  • Enables/Disables input
  • Logs off User
  • Hibernates
  • Shutdowns system
  • Reboots System
  • Performs network speed test
  • Manage Files
  • Manage Processes
  • Gathers the following information:
    • Client Overview:
      • Client ID used
      • Country
    • Software Information:
      • User Privelege
      • Machine Name
    • Hardware Information:
      • Machine Type
      • CPU Information
      • GPU Information
      • RAM Information
      • Battery
      • Monitor Count
    • Network Information:
      • WAN address
      • Download Speed
      • LAN Address
      • MAC Address
    • Others:
      • Security information
      • Uptime
      • Active Windows
      • Current malware file location
      • Full OS version
      • Keystroke logs
      • Stored passwords

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

  • dnspondy.{BLOCKED}s.org (IP address: {BLOCKED}.{BLOCKED}.26.78)

Information Theft

This backdoor logs a user's keystrokes to steal information.

Stolen Information

This backdoor saves the stolen information in the following file:

  • %All Users Profile%\{6 digits}\{6 digits}\{date}.txt - contains logged keystrokes

(Note: %All Users Profile% is the All Users folder, where it usually is C:\Documents and Settings\All Users on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData 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.)

  SOLUTION

Minimum Scan Engine: 9.8
FIRST VSAPI PATTERN FILE: 12.536.06
FIRST VSAPI PATTERN DATE: 19 May 2016
VSAPI OPR PATTERN File: 12.537.00
VSAPI OPR PATTERN Date: 20 May 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
    • Computer Helper = "%All Users Profile%\{6 digits}\helper.exe -a /a"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • Computer Helper = "%All Users Profile%\{6 digits}\helper.exe -a /a"
  • In HKEY_CURRENT_USER\Software
    • {base64 encoded data} = "{base64 encoded data}"

Step 5

To delete the added Scheduled Task:

For Windows 2000, Windows XP, and Windows Server 2003:

  1. Click on Start>Programs>Accessories>System Tools>Scheduled Tasks
  2. Double-click on a job file.
  3. Check if the malware path and file name is in the Run: box.
  4. If it does, delete the job file.
  5. Repeat step 2-4 for the remaining job files.

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

  1. Open the Windows Task Scheduler. To do this:
    • On Windows Vista, Windows 7, and Windows Server 2008, click Start, type taskschd.msc in the Search input field, then press Enter.
    • On Windows 8, Windows 8.1, and Windows Server 2012, right-click on the lower-left corner of the screen, click Run, type taskschd.msc, then press Enter.
  2. In the left panel, click Task Scheduler Library.
  3. In the upper-middle panel, select a Task.
  4. Check if the selected task starts the malware automatically. To do this, check the value in the Details column under the Actions tab in the lower-middle panel.
  5. If the malware path and file name is found, press DELETE and click Yes to delete the task.
  6. Repeat steps 3-5 for the remaining tasks.

Step 6

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.
  • %All Users Profile%\{41 characters}
  • %All Users Profile%\{6 digits}\{6 digits}\{date format}.txt

Step 7

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.
  • %All Users Profile%\{6 digits}
  • %All Users Profile%\{6 digits}\{6 digits}

Step 8

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


Did this description help? Tell us how we did.