Detection: gcp detect oauth token abuse

DEPRECATED DETECTION

This detection has been marked as deprecated by the Splunk Threat Research team. This means that it will no longer be maintained or supported. If you have any questions or concerns, please reach out to us at research@splunk.com.

Updated Date: 2024-08-15 ID: a7e9f7bb-8901-4ad0-8d88-0a4ab07b1972 Author: Rod Soto, Splunk Type: Hunting Product: Splunk Enterprise Security

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.

Search

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

Data Source

Name	Platform	Sourcetype	Source	Supported App
N/A	N/A	N/A	N/A	N/A

Macros Used

Name	Value
google_gcp_pubsub_message	`sourcetype="google:gcp:pubsub:message"`
gcp_detect_oauth_token_abuse_filter	`search *`

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

Annotations

- MITRE ATT&CK

+ Kill Chain Phases

+ NIST

+ CIS

- Threat Actors

ID	Technique	Tactic
T1078	Valid Accounts	Defense Evasion

KillChainPhase.DELIVERY

KillChainPhase.EXPLOITAITON

KillChainPhase.INSTALLATION

NistCategory.DE_AE

Cis18Value.CIS_10

APT18

APT28

APT29

APT33

APT39

APT41

Akira

Axiom

Carbanak

Chimera

Cinnamon Tempest

Dragonfly

FIN10

FIN4

FIN5

FIN6

FIN7

FIN8

Fox Kitten

GALLIUM

Ke3chang

LAPSUS$

Lazarus Group

Leviathan

OilRig

POLONIUM

PittyTiger

Sandworm Team

Silence

Silent Librarian

Suckfly

Threat Group-3390

Wizard Spider

menuPass

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Setting	Value
Disabled	true
Cron Schedule	`0 * * * *`
Earliest Time	`-70m@m`
Latest Time	`-10m@m`
Schedule Window	`auto`
Creates Risk Event	False

This configuration file applies to all detections of type hunting.

Implementation

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

Risk Based Analytics (RBA)

Risk Message	Risk Score	Impact	Confidence
tbd	25	50	50

The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

References

Detection Testing

Test Type	Status	Dataset	Source	Sourcetype
Validation	Not Applicable	N/A	N/A	N/A
Unit	❌ Failing	N/A	`N/A`	`N/A`
Integration	❌ Failing	N/A	`N/A`	`N/A`

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: GitHub | Version: 2