GCP: Pub/Sub Topic Created

Rule ID

PH_RULE_GCP_AUDIT_PUB_SUB_TOPIC_CREATED

Default Status

Enabled

Description

Google Cloud Platform: A Pub/Sub Topic has been created. Pub/Sub topics can be used to extract large amounts of audit or arbitrary data from GCP cloud, depending on what data is being published to the topic.

Severity

MITRE ATT&CK® Tactics

Collection

Collection consists of techniques adversaries may use to gather information and the sources information is collected from that are relevant to following through on the adversary's objectives. Frequently, the next goal after collecting data is to steal (exfiltrate) the data. Common target sources include various drive types, browsers, audio, video, and email. Common collection methods include capturing screenshots and keyboard input.

https://attack.mitre.org/tactics/TA0009

MITRE ATT&CK® Techniques

T1119

Automated Collection

Once established within a system or network, an adversary may use automated techniques for collecting internal data. Methods for performing this technique could include use of a Command and Scripting Interpreter to search for and copy information fitting set criteria such as file type, location, or name at specific time intervals. This functionality could also be built into remote access tools.

https://attack.mitre.org/techniques/T1119

Impacts

Network

Data Source

GCP via GOOGLE_Pub_Sub

Detection

Correlation

Remediation Guidance

Make sure it is an authorized change

Time Window

If the following pattern or patterns match an ingested event within the given time window in seconds, trigger an incident.

300 seconds

Trigger Conditions

If the following defined pattern/s occur within a 300 second time window.

topic_create

SubPattern Definitions

SubPattern Name: topic_create

This is the named definition of the event query, this is important if multiple subpatterns are defined to distinguish them.

SubPattern Query

This is the query logic that matches incoming events

eventType = "GCP_Audit_activity_Publisher_CreateTopic"  AND  resourceType = "pubsub_topic"

Group by Attributes

This defines how matching events are aggregated, only events with the same matching attribute values are grouped into one unique incident ID

emailId,topicName

Aggregate Constraint

This is most typically a numerical constraint that defines when the rule should trigger an incident

COUNT(*) >= 1

Incident Attribute Mapping

This section defines which fields in matching raw events should be mapped to the incident attributes in the resulting incident.

The available raw event attributes to map are limited to the group by attributes and the aggregate event constraint fields for each subpattern

 topicName=topic_create.topicName,
emailId=topic_create.emailId

FortiSIEM Rules