What Is Polymorphic Malware?
How Polymorphic Malware Works
Polymorphic malware leverages an encryption key to alter its shape, signature, and behavioral pattern. Using a mutation engine and a self-propagated code strain, it encrypts its code and changes how physical files are created. Many traditional cybersecurity solutions that rely on signature-based detection—a technique in which security systems identify a malware based on its known characteristics—fail to recognize or detect polymorphic threats.
A polymorphic attack typically involves the following stages.
Examples of Polymorphic Malware
Notable Polymorphic Attacks
Storm Email-Worm: In 2007, an infamous spam email with the subject "230 dead as storm batters Europe'' was responsible for up to 8 percent of all worldwide malware infections. When users opened the attachment in their email, the malware installed the wincom32 service and a Trojan on the recipient's machine, turning it into a bot. The malicious code used in the storm worm mutated every 30 minutes, making it difficult to detect with standard security tools.
Crypto Wall: From 2014 to 2015, CryptoWall used phishing emails and exploit kits to infiltrate devices and encrypt user data. The polymorphic ransomware strain evolved to create a new variant for every potential victim. The IC3 reported that more than $18 million was lost from the 992 victims that reported attacks during that time.
Beebone: In 2015, this botnet malware infected nearly 12,000 systems using a polymorphic downloader. The polymorphic attribute of this botnet made it challenging to track, requiring multiple international law enforcement agencies with sophisticated expertise and collaborative resources to take it down.
How to Defend Against Polymorphic Malware
While polymorphic malware may be difficult to detect, there are effective cybersecurity solutions to help prevent and defend against polymorphic attacks.
1. Establish a Comprehensive, Preventative Cybersecurity Strategy
Maintaining basic cybersecurity best practices, including email security hygiene, systems hardening across an organization, and staying informed and alert is key to improving cyber resilience and mitigating vulnerabilities.
2. Deploy Endpoint Security Solutions
Investing in Endpoint Security protects all end user's devices from cyberattacks and is essential for defending an organization’s network from threat actors. This security solution involves features like continuous monitoring, data loss protection, and incident response.
3. Use Zero Trust Network Access
Zero Trust Network Access (ZTNA) is a robust security solution that assumes no user or device should be automatically trusted within a network. It requires users to verify and authenticate themselves, reducing the potential for unauthorized access.
4. Build a Cybersecurity Culture
A robust security awareness training program is an effective preventative mechanism, as threat actors often leverage phishing scams as a gateway to install polymorphic malware. Educating and training users on how to identify and adequately respond to phishing scams and other cyber threats is vital.
5. Apply Security Patches and Updates
Maintaining a proactive system patching cadence is an effective method to prevent and defend against polymorphic malware. Applying security patches and vendor updates to all software, including operating systems, eliminates exploitable weaknesses that malware tends to latch onto.