Trojan.Win32.DOFOIL.AE

 Analysis by: Paul Steven Nadera

 ALIASES:

Trojan.Win32.Propagate.jmf (Kaspersky); Trojan:Win32/CryptInject.RA!eml (Microsoft); a variant of Win32/Kryptik.GQUD trojan (NOD32)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • 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 executes then deletes itself afterward.

As of this writing, the said sites are inaccessible.

It steals certain information from the system and/or the user.

It checks the operating system name of the affected computer.

  TECHNICAL DETAILS

File Size:

475,136 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

22 Mar 2019

Payload:

Connects to URLs/IPs, Steals information, Drops files, Terminates processes, Adds scheduled tasks, Deletes copies of itself after execution

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:

  • %Application Data%\Microsoft\Windows\{random name}\{random name}.exe

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

It executes then deletes itself afterward.

It adds the following mutexes to ensure that only one of its copies runs at any one time:

  • {generated hash based on system information}

Autostart Technique

This Trojan drops the following file(s) in the Windows User Startup folder to enable its automatic execution at every system startup:

  • %User Startup%\{random name}.lnk

(Note: %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows 2003(32-bit), XP and 2000(32-bit), or C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit), 10(64-bit).)

Process Termination

This Trojan terminates the following processes if found running in the affected system's memory:

  • tcpview.exe
  • Autoruns.exe
  • IDAQ.exe
  • OllyDbg.exe
  • idaq.exe
  • wireshark.exe
  • idaq64.exe
  • ProcessHacker.exe
  • idaw64.exe
  • idaw.exe
  • procmon.exe
  • procexp.exe
  • Tcpview.exe

Download Routine

This Trojan connects to the following URL(s) to download its component file(s):

  • http://{BLOCKED}6.co/zb/

As of this writing, the said sites are inaccessible.

Information Theft

This Trojan steals the following information:

  • Computer Name
  • Username
  • System Volume Information

Other Details

This Trojan connects to the following URL(s) to check for an Internet connection:

  • http://www.{BLOCKED}si.com/ncsi.txt

It checks the operating system name of the affected computer if it is any of the following:

  • Windows Vista or a latter version is required for it to run.

It does the following:

  • Extracts Window Class Names and terminates the process if it matches a hash from its list of hashes.
  • Checks for the presence of known sandbox IDs in the following registry keys:
    • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControLSet\Enum\SCSI
    where the sandbox IDs could be any of the following:
    • qemu
    • virtual
    • vmware
    • xen
  • It checks for the following DLL or modules if existing:
    • sbiedll
    If found, it terminates itself
  • It deletes traces of internet access by deleting the following files:
    • {malware name}:Zone Identifier

It does not proceed to its malicious routine if it detects that it is being debugged.

It adds the following scheduled tasks:

    • Task Name: Opera scheduled Autoupdate {hardcoded number}
    • Trigger: At 12:00 AM on 11/30/1999 - After triggered, repeat every 10 minutes indefinitely.
    • Action: %Application Data%\Microsoft\Windows\{random name}\{random name}.exe

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

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

14.888.03

FIRST VSAPI PATTERN DATE:

22 Mar 2019

VSAPI OPR PATTERN File:

14.889.00

VSAPI OPR PATTERN Date:

23 Mar 2019

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

Deleting Scheduled Tasks

The following {Task Name} - {Task to be run} listed should be used in the steps identified below:

  • Opera scheduled Autoupdate {hardcoded number} - %Application Data%\Microsoft\Windows\{random name}\{random name}.exe

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

  1. Open the Windows Scheduled Tasks. Click Start>Programs>Accessories>
    System Tools>Scheduled Tasks.
  2. Locate each {Task Name} values listed above in the Name column.
  3. Right-click on the said file(s) with the aforementioned value.
  4. Click on Properties. In the Run field, check for the listed {Task to be run}.
  5. If the strings match the list above, delete the task.

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, locate each {Task Name} values listed above in the Name column.
  4. In the lower-middle panel, click the Actions tab. In the Details column, check for the {Task to be run} string.
  5. If the said string is found, delete the task.

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.
  • %Application Data%\Microsoft\Windows\{random name}\{random name}.exe
  • %User Startup%\{random name}.lnk

Step 6

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