Okta MFA Exhaustion Hunt

Status: production
Group by: _time, user
Author: Michael Haag, Marissa Bower, Mauricio Velazco, Splunk
Source: github.com/splunk/security_content

The following analytic detects patterns of successful and failed Okta MFA push attempts to identify potential MFA exhaustion attacks. It leverages Okta event logs, specifically focusing on push verification events, and uses statistical evaluations to determine suspicious activity. This activity is significant as it may indicate an attacker attempting to bypass MFA by overwhelming the user with push notifications. If confirmed malicious, this could lead to unauthorized access, compromising the security of the affected accounts and potentially the entire environment.

MITRE ATT&CK coverage

Tactic	Techniques
Credential Access	`T1110` Brute Force

Rules detecting the same action

Other rules on this platform that filter on the same API call or operation.

MFA Fatigue (OKTA) (Kusto)
Okta MFA Bruteforce Attack (YARA-L)
Okta Mismatch Between Source And Response For Verify Push Request (YARA-L)
Okta Mismatch Between Source and Response for Verify Push Request (Splunk)

Rule body splunk

name: Okta MFA Exhaustion Hunt
id: 97e2fe57-3740-402c-988a-76b64ce04b8d
version: 9
creation_date: '2022-12-19'
modification_date: '2026-05-13'
author: Michael Haag, Marissa Bower, Mauricio Velazco, Splunk
status: production
type: Hunting
description: The following analytic detects patterns of successful and failed Okta MFA push attempts to identify potential MFA exhaustion attacks. It leverages Okta event logs, specifically focusing on push verification events, and uses statistical evaluations to determine suspicious activity. This activity is significant as it may indicate an attacker attempting to bypass MFA by overwhelming the user with push notifications. If confirmed malicious, this could lead to unauthorized access, compromising the security of the affected accounts and potentially the entire environment.
data_source:
    - Okta
search: |-
    `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 user,_time
      | stats latest(_time) as lasttime earliest(_time) as firsttime sum(successes) as successes sum(failures) as failures sum(pushes) as pushes
        BY 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)
      | `okta_mfa_exhaustion_hunt_filter`
how_to_implement: The analytic leverages Okta OktaIm2 logs to be ingested using the Splunk Add-on for Okta Identity Cloud (https://splunkbase.splunk.com/app/6553).
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.
references:
    - https://developer.okta.com/docs/reference/api/event-types/?q=user.acount.lock
    - https://sec.okta.com/everythingisyes
    - https://splunkbase.splunk.com/app/6553
analytic_story:
    - Okta Account Takeover
    - Okta MFA Exhaustion
    - Scattered Lapsus$ Hunters
asset_type: Okta Tenant
mitre_attack_id:
    - T1110
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: application
security_domain: access
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1621/okta_multiple_failed_mfa_pushes/okta_multiple_failed_mfa_pushes.log
          source: Okta
          sourcetype: OktaIM2:log
      test_type: unit

Stages and Predicates

Stage 1: `search`

`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))

Stage 2: `stats`

| 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 user,_time

Stage 3: `stats`

| stats latest(_time) as lasttime earliest(_time) as firsttime sum(successes) as successes sum(failures) as failures sum(pushes) as pushes
    BY user

Stage 4: `eval`

| eval seconds=lasttime-firsttime

Stage 5: `eval`

| eval lasttime=strftime(lasttime, "%c")

Stage 6: `search`

| search (pushes>1)

Stage 7: `eval`

| eval totalattempts=successes+failures

Stage 8: `eval`

| eval finding="Normal authentication pattern"

Stage 9: `eval`

| eval finding=if(failures==pushes AND pushes>1,"Authentication attempts not successful because multiple pushes denied",finding)

finding =

1."Authentication attempts not successful because multiple pushes denied"

-finding(default)

Stage 10: `eval`

| eval finding=if(totalattempts==0,"Multiple pushes sent and ignored",finding)

finding =

1."Multiple pushes sent and ignored"

-finding(default)

Stage 11: `eval`

| eval finding=if(successes>0 AND pushes>3,"Probably should investigate. Multiple pushes sent, eventual successful authentication!",finding)

finding =

ifsuccesses > 0 AND pushes > 3"Probably should investigate. Multiple pushes sent, eventual successful authentication!"

elsefinding

Stage 12: `search`

| `okta_mfa_exhaustion_hunt_filter`

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

Field	Kind	Values
`debugContext.debugData.factor`	eq	`OKTA_VERIFY_PUSH`
`eventType`	eq	`system.push.send_factor_verify_push`
`legacyEventType`	eq	`core.user.factor.attempt_fail` `core.user.factor.attempt_success`
`pushes`	gt	`1`
`sourcetype`	eq	`OktaIM2:log`

`j` / `k`	Scroll down / up
`d` / `u`	Half-page down / up
`gg` / `G`	Top / bottom
`h` / `l`	History back / forward
`f`	Follow link (`Shift` = new tab)
`/`	Focus search
`?`	Toggle this help
`↑` / `↓`	Navigate search results
`Enter`	Open highlighted result
`Esc`	Close results / dialog

`type:`	`events` / `rules` / `providers`
`vendor:`	`sigma` / `elastic` / `splunk` / `kusto` / `chronicle` (vendor name alone also works: `sigma:`, `kql:`, `secops:`…)
`tactic:`	TA-id, slug, or name: `credential_access`, `TA0006`
`technique:`	technique or sub-technique ID: `T1003`, `T1003.001` (alias `tech:`)
`severity:`	`critical` / `high` / `medium` / `low` / `informational` (alias `sev:`)
`risk_score`	Numeric comparison on the Elastic risk score (0 to 100): `risk_score>50`, `risk_score<=20`, `risk_score=99` (alias `risk`; Elastic rules only)
`stages:`	Rules with exactly N pipeline stages
`correlation:`	`single_event` / `sequence` / `alternatives` / `alternatives_cross_log` / `all_required` / `correlated`
`with:`	Co-occurrence event-id; stacks (`with:4624 with:4769`) to require all, while a comma list in one occurrence (`with:4624,4769`) is an either-or group. Implies multi-event
`like:`	Structural neighbors of a rule slug (equivalents + subsumption stricter / broader): `like:comsvcs_lsass_memory_dump-splunk-sysmon`
`groupby:`	Entity-grouping substring match against `group_by_keys`: `groupby:user`, `groupby:host`
`uses:`	Rules whose predicate tree touches the field (any kind, any value): `uses:CommandLine`
`excludes:`	Rules with top-level `not()` clauses on the field (FP whitelists): `excludes:ParentImage`
`field:` / `value:`	Predicate search; narrows rule cards to those with a matching leaf and drives the indicator tier. Unquoted = substring, wildcards allowed (`value:mimikatz`)
`indicator:`	Shorthand for `field:F value:V`: `indicator:Image=*\powershell.exe`
`kind:`	Filter by predicate kind. Narrows rule cards to those carrying a matching predicate leaf (`vendor:elastic kind:cidr_match`) and drives the indicator tier: `contains` / `starts_with` / `ends_with` / `regex` / `cidr` / `eq` / `in` … (operator aliases `op:`/`match:`)
`has:` / `no:`	`sample`, `field`, `notes`, `refs`, `trace`, `thirdparty`, `rule`, `pattern`, `timewindow`, `threshold`, `newterms`, `sigma`/`elastic`/`splunk`/`kusto`/`chronicle`
`-op:val`	Exclude matches; works on most operators but not `type:`/`like:`/`has:`/`no:` (use `no:<flag>` to exclude a rule flag): `tactic:execution -vendor:splunk`. Standalone `-kind:`/`-field:`/`-value:` drop every rule carrying a matching predicate leaf (`type:rules -kind:is_null`)
`field:"…"` / `value:"…"`	Quoted value = anchored exact match (also allows spaces): `value:"net user"`
`a,b`	Comma = OR inside one operator (`vendor:sigma,elastic`, `severity:high,critical`); repeating a facet merges the same way. `field:`/`value:` never split (literal commas)
`vendors:` / `stage:`	Singular and plural spellings fold to the canonical operator and value: `tactics:` = `tactic:`, `type:event` = `type:events`, `correlation:sequences` = `correlation:sequence`, `has:thresholds` = `has:threshold`
`"quoted phrase"`	Exact-match a multi-word phrase (free text)

Okta MFA Exhaustion Hunt

MITRE ATT&CK coverage

Rules detecting the same action

Rule body splunk

Stages and Predicates

Stage 1: `search`

Stage 2: `stats`

Stage 3: `stats`

Stage 4: `eval`

Stage 5: `eval`

Stage 6: `search`

Stage 7: `eval`

Stage 8: `eval`

Stage 9: `eval`

Stage 10: `eval`

Stage 11: `eval`

Stage 12: `search`

Indicators

Keyboard shortcuts

Search operators

Okta MFA Exhaustion Hunt

MITRE ATT&CK coverage

Rules detecting the same action

Rule body splunk

Stages and Predicates

Stage 1: search

Stage 2: stats

Stage 3: stats

Stage 4: eval

Stage 5: eval

Stage 6: search

Stage 7: eval

Stage 8: eval

Stage 9: eval

Stage 10: eval

Stage 11: eval

Stage 12: search

Indicators

Stage 1: `search`

Stage 2: `stats`

Stage 3: `stats`

Stage 4: `eval`

Stage 5: `eval`

Stage 6: `search`

Stage 7: `eval`

Stage 8: `eval`

Stage 9: `eval`

Stage 10: `eval`

Stage 11: `eval`

Stage 12: `search`