gcp detect oauth token abuse

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Description

This search provides detection of possible GCP Oauth token abuse. GCP Oauth token without time limit can be exfiltrated and reused for keeping access sessions alive without further control of authentication, allowing attackers to access and move laterally.

• Type: Hunting

• Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

• Last Updated: 2020-09-01
• Author: Rod Soto, Splunk
• ID: a7e9f7bb-8901-4ad0-8d88-0a4ab07b1972

Annotations

ATT&CK

ID	Technique	Tactic
T1078	Valid Accounts	Defense Evasion, Initial Access, Persistence, Privilege Escalation

Kill Chain Phase

• Exploitation

NIST

CIS20

CVE

Search

`google_gcp_pubsub_message` type.googleapis.com/google.cloud.audit.AuditLog 
|table protoPayload.@type protoPayload.status.details{}.@type protoPayload.status.details{}.violations{}.callerIp protoPayload.status.details{}.violations{}.type protoPayload.status.message  
| `gcp_detect_oauth_token_abuse_filter`

Macros

The SPL above uses the following Macros:

• google_gcp_pubsub_message

Note that gcp_detect_oauth_token_abuse_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required field

• _time

How To Implement

You must install splunk GCP add-on. This search works with gcp:pubsub:message logs

Known False Positives

GCP Oauth token abuse detection will only work if there are access policies in place along with audit logs.

Associated Analytic story

• GCP Cross Account Activity

RBA

Risk Score	Impact	Confidence	Message
25.0	50	50	tbd

Reference

• https://www.netskope.com/blog/gcp-oauth-token-hijacking-in-google-cloud-part-1
• https://www.netskope.com/blog/gcp-oauth-token-hijacking-in-google-cloud-part-2

Test Dataset

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

source | version: 1