Finally, we extracted and made available a list of 165 Snort signatures that were triggered on hosts with validated malware. We compare the characteristics of good and regular signatures and report a number of interesting statistics that provide essential guidelines for configuring Snort and for teaching good signature writing practices. In addition, we introduce a novel signature quality metric that can be exploited by security specialists to evaluate the available rulesets, prioritize the generated alerts, and facilitate the forensics analysis processes. Based on our metric, we compare the most popular signature rulesets and highlight differences.