PS1Bot malvertising: browser spawning script interpreter with encoded/IEX cmdline

Ibrahim Saud@tektrix

•updated Jun 24, 2026•0•0•4

This rule detects potential malvertising or drive-by download activity by identifying when common web browsers spawn script-interpreting processes (such as powershell.exe, cmd.exe, or mshta.exe) that execute suspicious commands indicative of obfuscation or payload delivery (e.g., IEX, EncodedCommand). It further correlates this activity with outbound network connections initiated by the child process within a 30-second window, which is characteristic of the second stage of a malware delivery chain.