Analysis by: Mohammed Malubay
ALIASES:

Fareit-FRP!9A89C823F2A9(NAI); Trojan:Win32/FormBook.AD!MTB(MICROSOFT);

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • 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 does not have any propagation routine.

It does not have any backdoor routine.

It does not have any information-stealing capability.

However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size: 65,536 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 31 Mar 2020
Payload: Connects to URLs/IPs, Drops files

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:

  • %User Profile%\subfolder1\filename1.exe

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name} on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It adds the following processes:

  • {execution file path}\{original filename}.exe
    • RegAsm.exe → injected with malicious code

It creates the following folders:

  • %User Profile%\subfolder1

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name} on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It injects codes into the following process(es):

  • RegAsm.exe → executed by the malware itself

Other System Modifications

This Trojan adds the following registry entries as part of its installation routine:

HKCU\Software\Microsoft\
Windows\CurrentVersion\RunOnce
Startup = "%User Profile%\subfolder1\filename1.exe"

Propagation

This Trojan does not have any propagation routine.

Backdoor Routine

This Trojan does not have any backdoor routine.

Rootkit Capabilities

This Trojan does not have rootkit capabilities.

Information Theft

This Trojan does not have any information-stealing capability.

Other Details

This Trojan does the following:

  • It connects to the following URL to download and execute code in memory:
    • https://drive.{BLOCKED}e.com/uc?export=download&id=1UCjHY1OzUC3otphBJHqkeTEetEVWM86W

However, as of this writing, the said sites are inaccessible.

It does not exploit any vulnerability.

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 15.776.07
FIRST VSAPI PATTERN DATE: 31 Mar 2020
VSAPI OPR PATTERN File: 15.777.00
VSAPI OPR PATTERN Date: 01 Apr 2020

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

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
    • Startup = "%User Profile%\subfolder1\filename1.exe"

Step 5

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.  
  • %User Profile%\subfolder1\filename1.exe

Step 6

Search and delete these folders

[ 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.
  • %User Profile%\subfolder1

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Trojan.Win32.SHELLOAD.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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