Experience Report: Using JA4+ Fingerprints for Malware Detection in Encrypted Traffic

Detection of malware communications is limited due to encryption. Malware control, updates, and distribution are encapsulated in TLS tunnels, making it difficult to distinguish between malicious and benign transmissions. One way, how to detect malware communication, is to analyze the TLS handshake and obtain so-called JA4+ fingerprints. This report analyses the effectiveness of JA4+ fingerprints for malware detection, focusing specifically on the JA4, JA4S and JA4X fingerprints and their accuracy. It examines the process of creating malware fingerprints, explores the uniqueness of these fingerprints across  different malware families and their ability to distinguish between malicious and benign applications. By examining the overlap and uniqueness, the study evaluates the effectiveness of using JA4+ fingerprints to detect malware in encrypted communications.