Analysis by: Karen Ivy Titiwa
ALIASES:

TrojanDownloader:O97M/EncDoc.AN!MTB (MICROSOFT); MSOffice/Agent.BAH!tr (FORTINET)

 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.

As of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size: 243,712 bytes
File Type: XLS
Memory Resident: Yes
Initial Samples Received Date: 16 Apr 2020
Payload: Connects to URLs/IPs, Displays message/message boxes

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 files:

  • %Public%\{Random number from 1-9999}.reg

(Note: %Public% is the folder that serves as a repository of files or folders common to all users, which is usually C:\Users\Public in Windows Vista, 7, and 8.)

It adds the following processes:

  • "%System%\reg.exe" EXPORT HKCU\Software\Microsoft\Office\12.0\Excel\Security %Public%\{Random number from 1-9999}.reg /y
  • "%System%\rundll32.exe" %Public%\CVR{Random number from 1000-9999}.tmp.cvr,DllRegisterServer

(Note: %Public% is the folder that serves as a repository of files or folders common to all users, which is usually C:\Users\Public in Windows Vista, 7, and 8.)

Download Routine

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

  • http://{BLOCKED}a.com//wp-content/themes/calliope/wp_data.php
  • http://{BLOCKED}ocde.com/wp-content/themes/calliope/wp_data.php

It saves the files it downloads using the following names:

  • %Public%\CVR{Random number from 1000-9999}.tmp.cvr

(Note: %Public% is the folder that serves as a repository of files or folders common to all users, which is usually C:\Users\Public in Windows Vista, 7, and 8.)

As of this writing, the said sites are inaccessible.

Other Details

This Trojan displays the following message boxes:

Displayed when download fails:

It does the following:

  • The macro will trigger upon having a value of 147.1 by the equation:
    • =FORMULA(3721/GET.CELL(19,B1)-GET.CELL(17,B1)*DAY(NOW()),AC186)

It deletes the following files to remove its traces in the system:

  • %Public%\{Random number from 1-9999}.reg

(Note: %Public% is the folder that serves as a repository of files or folders common to all users, which is usually C:\Users\Public in Windows Vista, 7, and 8.)

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 15.818.05
FIRST VSAPI PATTERN DATE: 21 Apr 2020
VSAPI OPR PATTERN File: 15.819.00
VSAPI OPR PATTERN Date: 22 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

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.
  • %Public%\CVR{Random number from 1000-9999}.tmp.cvr

Step 4

Scan your computer with your Trend Micro product to delete files detected as Trojan.X97M.FORMULOAD.AO. 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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