Question 140
A FortiAnalyzer 7.6 SOC analyst investigates this deployment: A third-party network sensor includes an attack type as a message suffix, but a parser anchored to the beginning of the line discards the suffix. Which ongoing safeguard best addresses the original risk?
Explanation
Correct Answer
Check field-completeness metrics rather than relying on parser match counts alone. This long-term control addresses the recurring risk. The technical reason is: A parser can successfully match a record yet omit fields outside its extraction pattern. A later acceptance test still needs to confirm: The normalized incident log contains the previously missing attack classification and source evidence.
Incorrect Answers
This safeguard, “Validate field data types and sample values during normalization acceptance tests”, reduces a different source-defined risk: A SOC attempts to compare blocked DNS queries across FortiGate and a third-party resolver, but the custom parser maps DNS query names to an IP-address field. That risk depends on: Query names and IP addresses have different meanings and data types; mapping them together corrupts cross-source analysis. The recurring problem here is a third-party network sensor includes an attack type as a message suffix, but a parser anchored to the beginning of the line discards the suffix. The originally selected control “Check field-completeness metrics rather than relying on parser match counts alone” is more specific because a parser can successfully match a record yet omit fields outside its extraction pattern.
This safeguard, “Add equivalent-value test cases to parser regression suites”, reduces a different source-defined risk: Two products describe a denied connection using `deny` and `blocked`, so cross-vendor searches miss half of equivalent outcomes. That risk depends on: Semantic normalization allows comparable events to be queried despite different producer vocabularies. The recurring problem here is a third-party network sensor includes an attack type as a message suffix, but a parser anchored to the beginning of the line discards the suffix. The originally selected control “Check field-completeness metrics rather than relying on parser match counts alone” is more specific because a parser can successfully match a record yet omit fields outside its extraction pattern.
This safeguard, “Teach analysts to separate collection, parser, and SIEM-indexing troubleshooting stages”, reduces a different source-defined risk: An event arrives in the correct ADOM raw device logs, but the administrator searches only the Fabric normalized All view and incorrectly concludes ingestion stopped. That risk depends on: Raw storage and SIEM-normalized indexing are separate processing stages and can succeed or fail independently. The recurring problem here is a third-party network sensor includes an attack type as a message suffix, but a parser anchored to the beginning of the line discards the suffix. The originally selected control “Check field-completeness metrics rather than relying on parser match counts alone” is more specific because a parser can successfully match a record yet omit fields outside its extraction pattern.