Since the early days of computers, computer viruses have existed. However, according to discovery, the Creeper program was the first noted computer virus; it was first created in 1971 with no malicious intent and was used to prove the possibility of creating a self-replicating program.

A computer virus is a malicious program with self-replication capability. Hence, it can replicate itself from one host to another. They will alter infected system settings and spread all connected devices across the network through pdf, MS document, image, or video file. When the user opens the infected file or the program, the virus executes and infects the user device and begins to spread to all connected devices.

While some computer viruses follow a funny purpose (e.g., display some images on an infected device screen), others can cause severe damage like steal user passwords, delete files, and prevent the operating system from booting. In addition, some virus types tend to install additional malware from the internet.

Computer viruses can spread using many ways; the most noticeable ones are:

  • Email attachments
  • Free internet programs
  • Malicious links are received via phishing emails, internet messaging applications such as WhatsApp, and social media platform messaging services (e.g., Facebook, Twitter).

This article will shed light on one type of computer virus, the Heuristic virus. See how it works and the best methods to remove it from infected systems.

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What is Heuristic Virus?

Heuristic virus, also known as Heur.Invader virus is a type of dangerous computer virus that causes serious harm to the infected operating system. It can alter its settings (Windows registry) and disable the installed antivirus/antimalware solution to install more malicious programs. Heur.Invader propagates primarily via email attachments and files downloaded from the internet.

A computer infected with this virus will generally have the following signs:

  1. The system will display messages about corrupted or missing system files
  2. Change the web browser homepage and default search engine
  3. Error messages about missing registry entries
  4. Strange processes names appear in the process list
  5. Pop-up advertisements
  6. Decrease system speed

The term "heuristic" comes from the way antivirus/antimalware programs detect malicious codes. To understand this word's origin, we need to talk a bit about how antiviruses detect malicious programs.

Antivirus detection methods

Antivirus software usually uses three primary methods for detecting, blocking, and removing viruses.

  1. Signature-based Detection: This is the classical detection method. The antivirus engine compares suspicious code to a database of signatures taken from the previously discovered viruses.
  2. Behavioural-based Detection: detects malicious programs by examining their intended suspicious behavior (e.g., a program that tries to monitor keystrokes or updating the host file will raise a red flag) before they execute it.
  3. Heuristic-based Detection: spots suspicious characteristics of a file and judges it accordingly. They employ different detection techniques, such as decompiling suspicious program code and then matching its code against a database containing previously discovered threats. Another detection method works by running the suspicious program inside a sandbox and checking its behavior after execution.

Heuristic analysis can detect malicious code without the need to identify its name (e.g., virus or malware name or strain), making it able to handle unknown and modern variants of viruses efficiently, compared with other detection methods.

Removing the Heuristic Virus type

Boot into the safe mode

It is advisable to boot into the safe mode; this makes Windows OS run with minimum drives and services. You can boot into safe mode under Windows 10 by following these steps:

  • Click the Windows button + I button to launch the Windows settings window
  • Select "Update and Security"
  • Select "Recovery"
  • Under Advanced startup, select Restart now
  • After the Windows restart, select Troubleshoot > Advanced options > Startup Settings > Restart (see Figure 1)
restart in safe mode

Figure 1: Restart in Safe Mode

  • After the Windows restart, press F4 to start your PC in Safe Mode.

Launching the infected PC in safe mode will prevent the heuristic virus from loading and disable your antivirus. Now, you need to install a new antivirus to remove the infection.

Install antivirus

While still in safe mode, install an antivirus to remove the infection. There are many antivirus solutions; most commercial antivirus vendors offer a trial period to test their products, while others offer a free version with limited functionality. The following gives links to download some popular free antivirus programs:

  1. Microsoft Safety Scanner (Portable version – always use the most current version, download it before the scan directly)
  2. McAfee GetSusp
  3. Kaspersky Virus Removal Tool
  4. McAfee Stinger
  5. Avast antivirus
  6. 360totalsecurity

What should users do in the future to avoid these infections?

To prevent future infection with viruses, make sure to follow these steps:

  1. Ensure operating system and installed applications are up to date.
  2. Please do not download and install internet programs unless they are from a reputable source.
  3. Install antivirus and antimalware and make sure to keep them up to date.
  4. Run full system scan periodically.
  5. Avoid phishing email.
  6. Do not visit or download contents from pirated websites, such as torrent and free file sharing websites.


Adversaries are almost always looking for new ways to infiltrate target systems and networks. A heuristic virus is like most other malicious code; however, it differs in replicating itself and can be used to install other dangerous malware. This article talked about this virus and suggested methods to remove it and to protect your device from similar virus attacks in the future.

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