Okta MFA Exhaustion Hunt
THIS IS A EXPERIMENTAL DETECTION
This detection has been marked experimental by the Splunk Threat Research team. This means we have not been able to test, simulate, or build datasets for this detection. Use at your own risk. This analytic is NOT supported.
The following analytic identifies patterns within Okta data to determine the amount of successful and failed pushes. Based on that, eval statements determine a finding of whether this is suspicious or not. The events are within a window of time and may be tuned as needed.
- Type: Hunting
Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Last Updated: 2022-09-27
- Author: Michael Haag, Marissa Bower, Splunk
- ID: 97e2fe57-3740-402c-988a-76b64ce04b8d
Kill Chain Phase
- CIS 16
1 2 3 4 5 6 7 8 9 10 11 12 13 14 `okta` eventType=system.push.send_factor_verify_push OR ((legacyEventType=core.user.factor.attempt_success) AND (debugContext.debugData.factor=OKTA_VERIFY_PUSH)) OR ((legacyEventType=core.user.factor.attempt_fail) AND (debugContext.debugData.factor=OKTA_VERIFY_PUSH)) | stats count(eval(legacyEventType="core.user.factor.attempt_success")) as successes count(eval(legacyEventType="core.user.factor.attempt_fail")) as failures count(eval(eventType="system.push.send_factor_verify_push")) as pushes by authenticationContext.externalSessionId,user,_time | stats latest(_time) as lasttime earliest(_time) as firsttime sum(successes) as successes sum(failures) as failures sum(pushes) as pushes by authenticationContext.externalSessionId,user | eval seconds=lasttime-firsttime | eval lasttime=strftime(lasttime, "%c") | search (pushes>1) | eval totalattempts=successes+failures | eval finding="Normal authentication pattern" | eval finding=if(failures==pushes AND pushes>1,"Authentication attempts not successful because multiple pushes denied",finding) | eval finding=if(totalattempts==0,"Multiple pushes sent and ignored",finding) | eval finding=if(successes>0 AND pushes>3,"Probably should investigate. Multiple pushes sent, eventual successful authentication!",finding) | where seconds<600 AND finding="Multiple pushes sent, eventual successful authentication!" AND totalattempts > 5 | sort - pushes, totalattempts | `okta_mfa_exhaustion_hunt_filter`
The SPL above uses the following Macros:
okta_mfa_exhaustion_hunt_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
List of fields required to use this analytic.
How To Implement
This analytic is specific to Okta and requires Okta logs to be ingested.
Known False Positives
False positives may be present. Tune Okta and tune the analytic to ensure proper fidelity. Modify risk score as needed. Drop to anomaly until tuning is complete.
Associated Analytic Story
|18.0||30||60||$src_user$ account has rejected multiple Okta pushes.|
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.
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source | version: 1