Author: Henry Alarcon Jr.   

 

HEUR:Trojan.BAT.Generic (Kaspersky), Trojan.Obfus.BAT.3.Gen (BitDefender)

 PLATFORM:

Windows

 OVER ALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 INFORMATION EXPOSURE
Low
Medium
High
Critical

  • Threat Type:
    Trojan

  • Destructiveness:
    No

  • Encrypted:
    No

  • In the wild:
    Yes

  OVERVIEW

INFECTION CHANNEL: Downloaded from the Internet, Dropped by other malware

This fileless malware connects to specific URLs to download PowerShell codes and execute these.

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 saves downloaded files into the said created folder.

  TECHNICAL DETAILS

File size: 627 bytes
File type: BAT
Memory resident: No
INITIAL SAMPLES RECEIVED DATE: 19 February 2019
PAYLOAD: Connects to URLs/IPs, Downloads 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 creates the following folders:

  • %Public%\Java_{6 random character}{1 random number}_

(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}.{BLOCKED}.52.26/loads/20938092830482 ← Powershell codes that will connect to other websites to download, extract and rename.
  • http://{BLOCKED}.{BLOCKED}.52.26/mods/al/md.zip ← downloaded of Powershell codes

It saves the files it downloads using the following names:

  • %Public%\Java_{6 random character}{1 random number}_\ex.png ← detected as Trojan.JS.BANKER.THBAIAI
  • %Public%\Java_{6 random character}{1 random number}_\Java_{6 random character}{1 random number}_.exe ← Autoit Sctipt Compiler
  • %Public%\Java_{6 random character}{1 random number}_\Java_{6 random character}{1 random number}_.LNS ← detected as TrojanSpy.Win32.BANRAP.AS
  • %Public%\Java_{6 random character}{1 random number}_\Java_{6 random character}{1 random number}_1.LNS ← Autoit script
  • %Public%\Java_{6 random character}{1 random number}_\libeay32.dll ← normal file
  • %Public%\Java_{6 random character}{1 random number}_\sqlite3.dll ← normal file
  • %Public%\Java_{6 random character}{1 random number}_\ssleay32.dll ← normal file
  • %Public%\i.dat ← where it saves its string used for files and folder name.
  • %Public%\c.lnk ← Target: Autoit compiler and autoit script
  • %User Startup%\ Java__{6 random character}{1 random number}_.lnk ← Target: Autoit script compiler and autoit script

It saves downloaded files into the said created folder.

Other Details

This Trojan does the following:

  • It executes the following command to restart the affected machine:
    • shutdown -r -t 200

  SOLUTION

Minimum scan engine: 9.850
First VSAPI Pattern File: 14.824.03
First VSAPI Pattern Release Date: 19 February 2019
VSAPI OPR PATTERN-VERSION: 14.825.00
VSAPI OPR PATTERN DATE: 20 February 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

Identify and terminate files detected as Trojan.BAT.BANLOAD.THBAIAI

[ learnMore ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 4

Search and delete these folders

[ learnMore ]
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.
  • %Public%\Java_{6 random character}{1 random number}_
  • %Public%\i.dat
  • %Public%\c.lnk
  • %User Startup%\ Java__{6 random character}{1 random number}_.lnk

Step 5

Scan your computer with your Trend Micro product to delete files detected as Trojan.BAT.BANLOAD.THBAIAI. 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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