Question

You are writing a YARA-L single-event rule to detect execution of any of roughly 40 known LOLBin process names (e.g., certutil.exe, mshta.exe, regsvr32.exe) derived from a threat intel report. During review, a colleague notes that chaining 40 separate `or` equality comparisons in the condition is hard to maintain and error-prone as the intel list grows. Which approach best expresses this match while keeping the rule maintainable and performant in Google SecOps?

Accepted Answer

Store the LOLBin process names in a reference list and use the `in` operator against `$e.principal.process.file.full_path` in the rule's events section

Answer

Convert the rule to a multi-event rule so each process name can be matched in its own event variable within a match window

Answer

Concatenate all 40 names into a single large regex alternation and apply it with `re.regex()` and `nocase` on the command line field

Answer

Hardcode all 40 `or` equality comparisons but move them into the `outcome` section so they are evaluated only after filtering