The 'Relevant ClamAV Message' detection rule is designed to identify specific messages output by the ClamAV antivirus software that indicate the presence of potential malware threats on Linux systems. This rule utilizes keyword matching to detect terms such as 'Trojan FOUND', 'VirTool FOUND', 'Webshell FOUND', 'Rootkit FOUND', and 'Htran FOUND'. By focusing on these keywords, the rule effectively alerts security teams to serious threats that may compromise system integrity or security. Implementing this rule requires monitoring logs from ClamAV, ensuring that any alerts generated signal necessary investigations or remediations against malware. This capability is crucial for maintaining a strong defense posture and minimizing the risks associated with malware infections in Linux environments.