This solution proposes using a Google SecOps SOAR job to automate the rule management lifecycle. The SOAR job would periodically fetch the list of currently restricted users, filtering out those whose five-day restriction has expired. It would then construct the YARA-L rule text with the updated user list and use the Chronicle API to deploy this new version of the rule. This approach centralizes the entire logic—data fetching, time-to-live (TTL) management, and rule deployment—into a single, maintainable automated workflow. While frequent rule deployment is not ideal for performance, it is a technically feasible and self-contained solution among the given options.

A. Detection rules, which run in the Chronicle SIEM component, cannot directly access or query data stored in Google SecOps SOAR global context values. This makes the proposed architecture non-functional.

C. This option is incorrect because Chronicle reference lists (referred to as data tables) do not support a multi-column structure with native time-to-live (TTL) functionality as described. The feature as stated does not exist.

D. Storing all users in a single, pipe-delimited row of a regex table is an improper and highly inefficient use of reference lists, which are designed to store one entry per row for optimal matching.

1. Chronicle Detection Engine API: The feasibility of option B is supported by the existence of the Chronicle Detection Engine API

which allows for programmatic creation and management of rules. A SOAR job can call this API to deploy updated rule versions.

Source: Google Cloud Documentation

"Chronicle Detection Engine API overview". See the section on the Rules service

which includes methods like CreateRule and DeleteRule.

2. Google SecOps SOAR Playbook Automation: SOAR playbooks can execute actions

including making HTTP requests to external APIs. This capability enables the SOAR job in option B to interact with the Chronicle API.

Source: Google Cloud Documentation

"Google SecOps SOAR overview". The documentation describes how playbooks automate security workflows by integrating various tools

which includes making API calls.

3. Chronicle Reference Lists (for disproving C): The structure of reference lists in Chronicle is a simple list of strings

CIDRs

or regular expressions

not a multi-column table. This confirms that the feature described in option C is not available.

Source: Google Cloud Documentation

"YARA-L 2.0 language syntax". The section on "Reference tables" describes them as a "list of values" and provides syntax like $event.field in %listname

which operates on a single list of items.