What is a Backdoor Virus? - Definition, Removal & Example

Instructor: Lyna Griffin

Lyna has tutored undergraduate Information Management Systems and Database Development. She has a Bachelor's degree in Electrical Engineering and a Masters degree in Information Technology.

In this lesson, we will define backdoor virus and explain how it works and the security risks it poses to any computer system, software or application. We will examine ways to remove backdoor viruses and minimize the risks to backdoors.

Going in the Backdoor

In layman's terms, a backdoor is normally a door that is obscured from the general public. It is not normally used as an active passage in the everyday working of things. In technology, the meaning is almost the same. A backdoor refers to an undisclosed point of access to a program, application or computer system in which the standard security procedures and authentication processes are bypassed.

Computer Backdoors

This secret backdoor access is sometimes a planned installation by system developers or service providers as a remote means for diagnostics, troubleshooting or other system tests. On the other hand, backdoor access can also be a system weakness or flaw or a malicious program which attackers can use to exploit the system and create their own backdoor.

A backdoor's mere existence is a huge security risk as potentially anyone can discover it and abuse it without detection. Whether the backdoor is a diagnostic tool, a malicious injection or a system flaw it is an entry point and a stepping stone to an enterprise-wide attack. There are some known system backdoors, however, that cannot be disabled. Additional security measures are needed to minimize the potential risks.

What is a Backdoor Virus?

A backdoor virus, therefore, is a malicious code which, by exploiting system flaws and vulnerabilities, is used to facilitate remote unauthorized access to a computer system or program. Like all malicious code, it works in the background oblivious to the victim. This access gives it total freedom to conduct malicious activities on the system. The system is now vulnerable to illicit file copying, modification, data stealing, and additional malicious injections.


There are many different types of backdoors which target different vulnerability spots in a system of application. A well-known backdoor example is called FinSpy. When installed on a system, it enables the attacker to download and execute files remotely on the system the moment it connects to the internet, irrespective of the system's physical location. It compromises overall system security. Firewall settings and other security configurations are changed. It is a difficult intrusion to detect with the attacker using random relatable file names. The malicious code runs on the system's startup routine.

Backdoor Removal

Backdoors are dangerous, run in stealth mode, and are almost impossible to manually detect. But, they must be removed. It is highly recommended that computer users adopt automatic system removal methods. In addition, strong firewalls and updated antivirus software must be in place. There are additional measures a system administrator can employ to minimize the risks of exposure, especially with the presence of legitimate backdoors intended for diagnostics, troubleshooting or other system tests.

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