Google Security-Operations-Engineer - Google Cloud Certified - Professional Security Operations Engineer (PSOE) Exam

Comprehensive and Detailed 150 to 250 words of Explanation From Exact Extract Google Security Operations Engineer documents:

The primary investigation tool for exploring relationships and historical activity in Google Security Operations is the UDM (Universal Data Model) search. The platform's curated views, such as the "User View," are built on top of this search capability.

To find all assets a user has interacted with, an analyst would perform a UDM search for the specific user (e.g., principal.user.userid = "suspicious_user") over the specified time range. The search results will include all UDM events associated with that user. Within these events, the analyst can examine all populated asset fields, such as principal.asset.hostname, principal.ip, target.resource.name, and target.user.userid (for interactions with service accounts).

This UDM search allows the analyst to pivot from the user entity to all related asset entities, directly answering the question of "what assets the user has interacted with." While the wording of Option A is slightly backward (it's more efficient to query for the user and find the hostnames), it is the only option that correctly identifies the UDM search as the tool used to find user-to-asset (hostname) relationships. Options B (Retrohunt), C (Raw Log Scan), and D (Ingestion Report) are incorrect tools for this investigative task.

(Reference: Google Cloud documentation, "Google SecOps UM Search overview"; "Investigate a user"; "Universal Data Model noun list")

Comprehensive and Detailed 150 to 250 words of Explanation From Exact Extract Google Security Operations Engineer documents:

The correct, low-impact solution for augmenting a Google-managed parser is to use a parser extension. The problem states that the base parser is still working, but needs to be supplemented to map two new fields.

Copying the entire parser (Option A) is a high-impact, high-maintenance solution ("Customer Specific Parser"). This action makes the organization responsible for all future updates and breaks the link to Google's managed updates, which is not a minimal-impact solution.

The intended, modern solution is the parser extension. This feature allows an engineer to write a small, targeted snippet of Code-Based Normalization (CBN) code that executes after the Google-managed base parser. This extension code can access the raw_log and perform the specific logic needed to extract the two unmapped fields and assign them to their proper Universal Data Model (UDM) fields.

This approach is the fastest to deploy and minimizes change management impact because the core parser remains managed and updated by Google, while the extension simply adds the custom logic on top. Option B, "Extract Additional Fields," is a UI-driven feature, but the underlying mechanism that saves and deploys this logic is the parser extension. Option D is the more precise description of the technical solution.

(Reference: Google Cloud documentation, "Manage parsers"; "Parser extensions"; "Code-Based Normalization (CBN) syntax")

Comprehensive and Detailed 150 to 250 words of Explanation From Exact Extract Google Security Operations Engineer documents:

The core of this problem is the unreliable data quality for the file hash. A robust detection strategy cannot depend on an unreliable data point. Options B and C are weak because they create a dependency on the SHA256 hash, which the prompt states is "not reliably captured." This would lead to missed detections. Option A is far too broad and would generate massive noise.

The best detection engineering practice is to use the reliable IoCs in a flexible and high-performance manner. The domain is a reliable IoC (from DNS logs), and the hash is still a valuable IoC, even if it's only intermittently available.

The standard Google SecOps method for this is to create a List (referred to here as a "data table") containing both static IoCs: the hash and the domain. An engineer can then write a single, efficient YARA-L rule that references this list. This rule would trigger if either a PROCESS_LAUNCH event is seen with a hash in the list or a NETWORK_DNS event is seen with a domain in the list (e.g., (event.principal.process.file.sha256 in %ioc_list) or (event.network.dns.question.name in %ioc_list)). This creates a resilient detection mechanism that provides two opportunities to identify the threat, successfully working around the unreliable data problem.

(Reference: Google Cloud documentation, "YARA-L 2.0 language syntax"; "Using Lists in rules"; "Detection engineering overview")

Comprehensive and Detailed Explanation

The correct solution is Option D. The problem is that a known, trusted principal (the backup tool's service account) is performing a legitimate action (storage.objects.list) that happens to look like the suspicious behavior the rule is designed to catch.

The most precise and effective way to reduce these false positives without weakening the rule's ability to catch malicious actors is to create an exception for the trusted principal.

By adding principal.user.email != "backup-bot@fcobaa.com" (or the equivalent principal.user.userid) to the events or condition section of the YARA-L rule, the rule will now only evaluate events where the actor is not the known-good backup bot.

Option A is incorrect because it just lowers the priority of the false positive; it doesn't stop it from being generated.

Option B is incorrect because the legitimate tool might also perform repeated calls, leading to the same false positive.

Option C is incorrect because api.service_name = "storage.googleapis.com" is less specific than api.operation = "storage.objects.list" and would likely increase the number of false positives by triggering on any storage API call.

Exact Extract from Google Security Operations Documents:

Reduce false positives: When a detection rule generates false positives due to known-benign activity (e.g., from an administrative script or automation tool), the best practice is to add a not condition to the rule to exclude the trusted entity.8

You can filter on UDM fields to create exceptions. For example, to prevent a rule from firing on activity from a specific service account, you can add a condition to the events section such as:

and $e.principal.user.userid != "trusted-service-account@project.iam.gserviceaccount.com"

This technique, often called "allow-listing" or "suppression," improves the rule's accuracy by focusing only on unknown or untrusted principals.

Comprehensive and Detailed Explanation

The correct answer is Option A. This question is about entity context enrichment and aliasing.

Endpoint telemetry from EDR and Windows Event Logs (like 4624) identifies users by their Windows Security Identifier (SID) (e.g., S-1-5-21-12345...). However, detection rules are more effective when they match on a human-readable and consistent identifier, like an email address or username, which is stored in principal.user.userid.

To "connect the dots" between the SID found in endpoint events and the userid, Google SecOps must ingest an authoritative user context data source. In a modern Windows environment, this source is Microsoft Entra ID (formerly Azure AD) or on-premises Active Directory.

Ingesting Entra ID logs as a USER_CONTEXT feed populates the SecOps entity graph. This allows the platform to automatically alias the SID from an endpoint log to the corresponding userid (e.g., jsmith@company.com) at ingestion time. This ensures the principal.user.userid field is correctly populated, allowing the detection rules to match.

Options B, C, and D are all additional event sources (like EDR) and would provide more SIDs, but they do not provide the central directory data needed to perform the aliasing.

Exact Extract from Google Security Operations Documents:

UDM enrichment and aliasing overview: Google Security Operations (SecOps) supports aliasing and enrichment for assets and users. Aliasing enables enrichment. For example, using aliasing, you can find the job title and employment status associated with a user ID.

How aliasing works: User aliasing uses the USER_CONTEXT event type for aliasing. This contextual data is stored as entities in the Entity Graph. When new Unified Data Model (UDM) events are ingested, enrichment uses this aliasing data to add context to the UDM event. For example, an EDR log might contain a principal.windows_sid. The enrichment process queries the entity graph (populated by your Active Directory or Entra ID feed) and populates the principal.user.userid and other fields in the principal.user noun.