Overview

This article will explain the ACSIA alert called "malicious HTA file".

Explaining the malicious HTA file

"Malicious HTA file" refers to a file with the .hta extension that contains hidden code or scripts designed by an attacker to carry out harmful actions on a computer system. HTA stands for "HTML Application," and these files can execute scripts using the same technologies as web pages, making them potentially dangerous if used maliciously.

Example of a "malicious HTA file" attack:

Let's consider a scenario where an attacker wants to gain unauthorized access to a company's network. The attacker decides to use a "malicious HTA file" as a means of initiating the attack.

To begin the attack, the attacker crafts an HTA file that looks like a harmless document or a legitimate application. They then use various social engineering techniques, such as sending the file through email, to trick an employee into opening it.

Once the unsuspecting employee opens the HTA file, it executes the hidden malicious code embedded within it. The code is designed to exploit vulnerabilities in the computer system and gain unauthorized access.

For example, the HTA file might run a script that installs backdoor software on the employee's computer, allowing the attacker to control it remotely. With control over the employee's computer, the attacker can now use it as a foothold to pivot further into the company's network.

From this initial point of access, the attacker can explore the company's network, search for sensitive information, or attempt to escalate their privileges to gain access to more critical systems and data.

The "malicious HTA file" attack demonstrates how attackers can use seemingly innocent files to infiltrate computer systems and networks. Due to the hidden nature of the malicious code in the HTA file, it may not be immediately obvious to the user that the file is dangerous. 

ACSIA alerts you when there is an attempt to download an HTA file on your infrastructure.