Suspicious ADS File Creation Outside Browser Download
Detects the creation of a suspicious Alternate Data Stream (ADS) file, specifically a ':Zone.Identifier' stream, by processes other than common web browsers. The ':Zone.Identifier' ADS is used by Windows to mark files downloaded from the internet, indicating their origin and often triggering security warnings. This rule looks for the creation of this ADS with a 'ZoneId=3' (indicating an internet origin) on executable or document file types. By filtering out known browser processes, the rule aims to identify instances where other applications or scripts might be creating these ADS files, potentially as a defense evasion technique to bypass security warnings or to masquerade malicious files.
Sigma
