Polymorphic malware is a type of malicious software that can change its code structure while maintaining its core functionality, making it difficult for traditional signature-based antivirus solutions to detect. It uses a mutation engine to create new variants by altering its code through techniques like code obfuscation, encryption, and junk code insertion. There are several categories of polymorphic malware, including polymorphic viruses, trojans, rootkits, and ransomware, each with unique characteristics. Detection of polymorphic malware is challenging due to its ability to evade conventional methods, prompting the use of behavioral analysis and machine learning for identification. To protect against such threats, a multi-layered security approach is recommended, including regular software updates, network segmentation, and employee training. Real-world examples like the Storm Worm and Conficker worm illustrate the significant impact of polymorphic malware, which has caused substantial financial losses. As cybersecurity measures advance, polymorphic malware continues to evolve, incorporating artificial intelligence and machine learning, leading to new challenges for security professionals. Cloud-based security solutions are emerging as effective tools to combat these threats.