Fileless malware is defined as a type of malicious software that does not rely on virus-laden files to infect a host or victim. In contrast, it makes use of applications that are commonly used to perform legitimate and justified activity for executing malicious code in resident memory of the host. As the software doesn’t create any files, it doesn’t leave any footprints making it difficult to detect and remove.

Key Targets Of Fileless Malware:

The attackers who employ fileless malware tend to gather large amount of information in short span of time. So, they tend to focus the attack on a few key targets. Two systems that form common target are:

  • PowerShell
  • Windows Management Instrumentations

The reasons why attackers choose these systems are:

  • Security technologies trust these utilities
  • Analysts tend to assume that actions of these systems are legitimate
  • These utilities provide complete control over an endpoint
  • Most organizations refrain from shutting down these systems as it will hinder business It or DevOps work

Working Of Fileless Malware:

Following are few scenarios in which fileless malware can use a system’s software, applications and protocols to install and execute malicious activity:

  • Phishing emails, malicious downloads, and links that look legitimate are used as points of entry. Once a user clicks on these links, they load to system’s memory. This enables the hackers to remotely load codes to steal confidential data.
  • Malicious code can be injected into applications that are already installed on the system and trusted by the user. After injecting the code, these applications are hijacked and executed by hackers to carry out malicious activity.
  • Attackers create fake websites that mimic legitimate business pages. When user visits these pages, the websites search for vulnerabilities in Flash plugin. These vulnerabilities are exploited to run malicious code in the browser memory.

Fileless malware is written directly to RAM of the infected system and no changes are made on the hard disk. The malware works in memory and the operations end when the system reboots.

Defending Against Fileless Malware Attacks:

The effective way to defend against fileless malware attacks is to adopt an integrated approach that addresses the entire threat lifecycle. Employing a multi-layer defense protocol enables the user to investigate every phase before, during and after the attack.

For more information on fileless malware and tips on preventing cyber-attacks on computer networks, contact Centex Technologies at (254) 213 – 4740.