PUA_RAFOTECH

June 13, 2017
 Analysis by: Ryan Paolo Maglaque
 ALIASES:

Trojan.Fireball(Norton);Riskware/Elex(Fortinet);

 PLATFORM:

Windows

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

  • Threat Type: Potentially Unwanted Application

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet, Dropped by other malware

This Potentially Unwanted Application arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites. It arrives as a component bundled with malware/grayware packages.

It uses Windows Task Scheduler to create a scheduled task that executes the dropped copy.

It modifies the Internet Explorer Zone Settings.

It connects to certain websites to send and receive information.

  TECHNICAL DETAILS

File Size:

996,352 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

29 Nov 2016

Payload:

Connects to URLs/IPs

Arrival Details

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

It arrives as a component bundled with malware/grayware packages.

Installation

This Potentially Unwanted Application drops the following files:

  • %Program Files%\Common Files\Services\iThemes.dll
  • {Malware Directory}\Archer.dat
  • %ProgramData%\ChelfNotify\{Program used to run the dll}
  • %ProgramData%\ChelfNotify\{Malware Dll copy}
  • {Malware Directory}\lanceruse.dat
  • %ProgramData%\WinSAPSvc\{Malware Dll copy}

(Note: %Program Files% is the Program Files folder, where it usually is C:\Program Files on all Windows operating system versions; C:\Program Files (x86) for 32-bit applications running on Windows 64-bit operating systems.. %ProgramData% is the Program Data folder, where it usually is C:\Program Files in Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData in 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 Windows Task Scheduler to create a scheduled task that executes the dropped copy.

Autostart Technique

The scheduled task executes the malware every:

  • Hour

Other System Modifications

This Potentially Unwanted Application adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Screenshot

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\Themes
DependOnService = iThemes5

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\WinSAPSvc\Parameters
ServiceDll = %ProgramData%\WinSAPSvc\{Malware Dll copy}

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
MRT.exe
Debugger = {Malware File Path} -Yrrehs

Web Browser Home Page and Search Page Modification

This Potentially Unwanted Application modifies the Internet Explorer Zone Settings.

Other Details

This Potentially Unwanted Application connects to the following website to send and receive information:

  • http://{BLOCKED}fyb3wv3k.cloudfront.net
  • http://{BLOCKED}kt858uv.cloudfront.net
  • http://{BLOCKED}oswufp5k.cloudfront.net
  • http://{BLOCKED}umnsgtu.cloudfront.net
  • http://{BLOCKED}nloqrqmu.cloudfront.net
  • http://{BLOCKED}kz9qye2.cloudfront.net

It does the following:

  • Create a schedule task via:
    • schtasks /Create /SC HOURLY /MO 2 /ST 00:53:00 /TN "ChelfNotify Task" /TR "\"C:\ProgramData\ChelfNotify\{File}\" \"C:\ProgramData\ChelfNotify\{Malware File}\",Rundll32_Do -do" /RU "SYSTEM" /F /RL HIGHEST
  • Can execute the following commands via exported functions:
    • MAIN(export function)
    • -update ← update the malware
    • -install ← create registry
    • -uninstall ← uninstall registry changes
    • Rundll32_Do and SignalChromeElf(export function)
    • -is ← create scheduled task
    • -us ← uninstall scheduled task
    • -do ← connects to the sites

  SOLUTION

Minimum Scan Engine:

9.850

SSAPI PATTERN File:

1.845.00

SSAPI PATTERN Date:

08 Jun 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

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\MRT.exe
    • Debugger = {Malware File Path} -Yrrehs
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\services\WinSAPSvc\Parameters
    • ServiceDll = %ProgramData%\WinSAPSvc\{Malware Dll copy}
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\services\Themes
    • DependOnService = iThemes5

Step 4

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.
  • %ProgramData%\ChelfNotify\{Exe used to run dll}
  • %ProgramData%\ChelfNotify\{Dll Copy}
  • {Malware Directory}\lanceruse.dat
  • {Malware Directory}\Archer.dat
  • %ProgramData%\WinSAPSvc\{Malware copy}
  • %Program Files%\Common Files\Services\iThemes.dll

Step 5

Delete the Scheduled Tasks added by this malware/grayware

[ Learn More ]

To delete the added Scheduled Task file:

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

  1. Open the Windows Scheduled Tasks. To do this, click Start>Programs>Accessories>System Tools>Scheduled Tasks.
  2. Double-click on a .JOB file.
  3. Check if the malware path and file name exists in the .JOB file. To do this, check the value in the Run field.
  4. If found, select the .JOB file then press SHIFT+DELETE to permanently delete the file.
  5. Repeat the steps above 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 of the Task Scheduler Window, click Task Scheduler Library.
  3. In the upper-middle panel, click a Task.
  4. In the lower middle panel, click the Actions tab
  5. Check if the malware path and file name exists in the task. To do this, check the value in the Details column under the Actions tab.
  6. If found, select the task and press DELETE and click Yes to delete the task.
  7. Repeat the steps above for the remaining tasks.

Step 6

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

Step 7

Reset Internet security settings

[ Learn More ]


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