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What is a Polymorphic Virus?
9/27/2023 - Brian O'Neill

To effectively detect, mitigate and/or remove virus threats, it’s important we first understand the unique characteristics that set certain virus types apart from others.

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What defines a polymorphic virus, and why is it effective?

By definition, all computer viruses seek to replicate themselves so they can spread across multiple files and throughout one or more systems. While some virus types retain their original signature during the replication process, polymorphic viruses do not. Instead, viruses of this type alter the appearance of their code to disguise themselves from signature-based virus scanning engines. They often encrypt their code and rapidly change encryption keys to alter the makeup of infected files, relying on complex mutation engines in that process.

As a result, even if a basic signature-based virus detection engine manages to identify one infected file within a system, it may not be capable of identifying other files infected by subsequent iterations of the polymorphic virus. If the victim of a cyberattack believes the threat within their system has been neutralized, when it in fact hasn't, the virus may be able to proliferate much more extensively throughout their system.

How can polymorphic virus threats be detected?

Identifying elusive polymorphic threats requires a dynamic & proactive virus scanning approach. To that end, rather than solely referencing a database of known virus signatures, advanced virus scanning solutions can additionally apply heuristic or even behavior-based analysis techniques. Heuristic detection techniques rely on algorithms with rulesets designed to identify malware based on patterns, while behavior-based techniques look at the way computer programs perform to identify “symptoms” of otherwise undetected malware.

Identifying polymorphic viruses with the Cloudmersive Virus Scan API

The Cloudmersive Virus Scan API is a turn-key solution designed to detect a wide range of virus & malware types – including Polymorphic viruses – through a combination of file hashing, signal extraction, pattern matching, heuristics, whitelisting, bytecode analysis, and certificate analysis. For more information, please do not hesitate to reach out to a member of our sales team.

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