Potential Okta Credential Stuffing (Single Source)

  1[metadata]
  2creation_date = "2024/06/17"
  3integration = ["okta"]
  4maturity = "production"
  5updated_date = "2026/02/19"
  6
  7[rule]
  8author = ["Elastic"]
  9description = """
 10Detects potential credential stuffing attacks where a single source IP attempts authentication against many Okta
 11user accounts with minimal attempts per user, indicating the use of breached credential lists.
 12"""
 13false_positives = [
 14    "Corporate proxy or VPN exit nodes may aggregate traffic from multiple legitimate users.",
 15    "Shared systems such as kiosks or conference room computers may have multiple users authenticating.",
 16]
 17from = "now-15m"
 18language = "esql"
 19license = "Elastic License v2"
 20name = "Potential Okta Credential Stuffing (Single Source)"
 21note = """## Triage and analysis
 22
 23### Investigating Potential Okta Credential Stuffing (Single Source)
 24
 25This rule identifies a single source IP attempting authentication against many user accounts with minimal attempts per user. This pattern indicates credential stuffing where attackers rapidly test breached username and password pairs.
 26
 27#### Possible investigation steps
 28- Identify the source IP and determine if it belongs to known proxy, VPN, or cloud infrastructure.
 29- Review the list of targeted user accounts and check if any authentications succeeded.
 30- Examine the user agent strings for signs of automation or scripting tools.
 31- Check if Okta flagged the source as a known threat or proxy.
 32- Determine if any targeted accounts have elevated privileges or access to sensitive systems.
 33- Review the geographic location and ASN of the source IP for anomalies.
 34
 35### False positive analysis
 36- Corporate proxies or VPN exit nodes may aggregate traffic from multiple legitimate users.
 37- Shared systems such as kiosks or conference room computers may have multiple users authenticating.
 38- Legitimate SSO integrations may generate multiple authentication attempts from a single source.
 39
 40### Response and remediation
 41- If attack is confirmed, block the source IP at the network perimeter.
 42- Reset passwords for any accounts that may have been compromised.
 43- Enable or strengthen MFA for targeted accounts.
 44- Review Okta sign-on policies to add additional friction for suspicious authentication patterns.
 45- If this is a known legitimate source, consider adding an exception for the IP or ASN.
 46"""
 47references = [
 48    "https://support.okta.com/help/s/article/Troubleshooting-Distributed-Brute-Force-andor-Password-Spray-attacks-in-Okta",
 49    "https://www.okta.com/identity-101/brute-force/",
 50    "https://support.okta.com/help/s/article/How-does-the-Device-Token-work?language=en_US",
 51    "https://developer.okta.com/docs/reference/api/event-types/",
 52    "https://www.elastic.co/security-labs/testing-okta-visibility-and-detection-dorothy",
 53    "https://sec.okta.com/articles/2023/08/cross-tenant-impersonation-prevention-and-detection",
 54    "https://www.okta.com/resources/whitepaper-how-adaptive-mfa-can-help-in-mitigating-brute-force-attacks/",
 55    "https://www.elastic.co/security-labs/monitoring-okta-threats-with-elastic-security",
 56    "https://www.elastic.co/security-labs/starter-guide-to-understanding-okta",
 57]
 58risk_score = 47
 59rule_id = "94e734c0-2cda-11ef-84e1-f661ea17fbce"
 60setup = "The Okta Fleet integration, Filebeat module, or similarly structured data is required to be compatible with this rule."
 61severity = "medium"
 62tags = [
 63    "Domain: Identity",
 64    "Use Case: Identity and Access Audit",
 65    "Data Source: Okta",
 66    "Data Source: Okta System Logs",
 67    "Tactic: Credential Access",
 68    "Resources: Investigation Guide",
 69]
 70timestamp_override = "event.ingested"
 71type = "esql"
 72
 73query = '''
 74FROM logs-okta.system-* METADATA _id, _version, _index
 75| WHERE
 76    event.dataset == "okta.system"
 77    AND (event.action LIKE "user.authentication.*" OR event.action == "user.session.start")
 78    AND okta.outcome.reason IN ("INVALID_CREDENTIALS", "LOCKED_OUT")
 79    AND okta.actor.alternate_id IS NOT NULL
 80// Build user-source context as JSON for enrichment
 81| EVAL Esql.user_source_info = CONCAT(
 82    "{\"user\":\"", okta.actor.alternate_id,
 83    "\",\"ip\":\"", COALESCE(okta.client.ip::STRING, "unknown"),
 84    "\",\"user_agent\":\"", COALESCE(okta.client.user_agent.raw_user_agent, "unknown"), "\"}"
 85  )
 86// FIRST STATS: Aggregate by (IP, user) to get per-user attempt counts
 87// This prevents skew from outlier users with many attempts
 88| STATS
 89    Esql.user_attempts = COUNT(*),
 90    Esql.user_dt_hashes = COUNT_DISTINCT(okta.debug_context.debug_data.dt_hash),
 91    Esql.user_source_info = VALUES(Esql.user_source_info),
 92    Esql.user_agents_per_user = VALUES(okta.client.user_agent.raw_user_agent),
 93    Esql.devices_per_user = VALUES(okta.client.device),
 94    Esql.is_proxy = VALUES(okta.security_context.is_proxy),
 95    Esql.geo_country = VALUES(client.geo.country_name),
 96    Esql.geo_city = VALUES(client.geo.city_name),
 97    Esql.asn_number = VALUES(source.as.number),
 98    Esql.asn_org = VALUES(source.as.organization.name),
 99    Esql.threat_suspected = VALUES(okta.debug_context.debug_data.threat_suspected),
100    Esql.risk_level = VALUES(okta.debug_context.debug_data.risk_level),
101    Esql.risk_reasons = VALUES(okta.debug_context.debug_data.risk_reasons),
102    Esql.event_actions = VALUES(event.action),
103    Esql.first_seen_user = MIN(@timestamp),
104    Esql.last_seen_user = MAX(@timestamp)
105  BY okta.client.ip, okta.actor.alternate_id
106// SECOND STATS: Aggregate by IP to detect credential stuffing pattern
107// Now we can accurately measure the distribution of attempts across users
108| STATS
109    Esql.unique_users = COUNT(*),
110    Esql.total_attempts = SUM(Esql.user_attempts),
111    Esql.max_attempts_per_user = MAX(Esql.user_attempts),
112    Esql.min_attempts_per_user = MIN(Esql.user_attempts),
113    Esql.avg_attempts_per_user = AVG(Esql.user_attempts),
114    Esql.users_with_single_attempt = SUM(CASE(Esql.user_attempts == 1, 1, 0)),
115    Esql.users_with_few_attempts = SUM(CASE(Esql.user_attempts <= 2, 1, 0)),
116    Esql.first_seen = MIN(Esql.first_seen_user),
117    Esql.last_seen = MAX(Esql.last_seen_user),
118    Esql.target_users = VALUES(okta.actor.alternate_id),
119    Esql.user_source_mapping = VALUES(Esql.user_source_info),
120    Esql.event_action_values = VALUES(Esql.event_actions),
121    Esql.user_agent_values = VALUES(Esql.user_agents_per_user),
122    Esql.device_values = VALUES(Esql.devices_per_user),
123    Esql.is_proxy_values = VALUES(Esql.is_proxy),
124    Esql.geo_country_values = VALUES(Esql.geo_country),
125    Esql.geo_city_values = VALUES(Esql.geo_city),
126    Esql.source_asn_values = VALUES(Esql.asn_number),
127    Esql.source_asn_org_values = VALUES(Esql.asn_org),
128    Esql.threat_suspected_values = VALUES(Esql.threat_suspected),
129    Esql.risk_level_values = VALUES(Esql.risk_level),
130    Esql.risk_reasons_values = VALUES(Esql.risk_reasons)
131  BY okta.client.ip
132// Calculate stuffing signature: most users should have very few attempts
133| EVAL Esql.pct_users_few_attempts = Esql.users_with_few_attempts * 100.0 / Esql.unique_users
134// Credential stuffing: many users, most with 1-2 attempts each, low max per user
135// Stacked stats gives us accurate per-user distribution instead of skewed averages
136| WHERE
137    Esql.total_attempts >= 25
138    AND Esql.unique_users >= 15
139    AND Esql.max_attempts_per_user <= 2
140    AND Esql.pct_users_few_attempts >= 80.0
141| SORT Esql.unique_users DESC
142| KEEP Esql.*, okta.client.ip
143'''
144
145
146[[rule.threat]]
147framework = "MITRE ATT&CK"
148[[rule.threat.technique]]
149id = "T1110"
150name = "Brute Force"
151reference = "https://attack.mitre.org/techniques/T1110/"
152[[rule.threat.technique.subtechnique]]
153id = "T1110.004"
154name = "Credential Stuffing"
155reference = "https://attack.mitre.org/techniques/T1110/004/"
156
157
158[rule.threat.tactic]
159id = "TA0006"
160name = "Credential Access"
161reference = "https://attack.mitre.org/tactics/TA0006/"