Detection rules › Panther
Anthropic SSO Login Failed
Detects failed SSO login attempts to the Anthropic organization. The actor is unauthenticated so no email is available — only the source IP. Every failure is alerted on as SSO failures should be rare in normal operation.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Credential Access | T1110 Brute Force |
Rule body yaml
AnalysisType: rule
RuleID: Anthropic.Activity.SSO.Login.Failed
DisplayName: "Anthropic SSO Login Failed"
Enabled: true
Filename: anthropic_sso_login_failed.py
LogTypes:
- Anthropic.Activity
Severity: Medium
Description: >
Detects failed SSO login attempts to the Anthropic organization. The actor
is unauthenticated so no email is available — only the source IP. Every
failure is alerted on as SSO failures should be rare in normal operation.
Runbook: |
1. Find all Anthropic.Activity SSO events (sso_login_initiated, sso_login_succeeded, sso_login_failed) from actor:ip_address in the 1 hour before and after the alert to determine if this was a one-off or part of a burst
2. Check if actor:ip_address appears in threat intelligence feeds or is associated with known VPN/proxy services
3. Check if actor:ip_address has been seen in successful sso_login_succeeded events in the past 30 days to determine if this is a known user IP
Tags:
- Anthropic
- Authentication
Reports:
MITRE ATT&CK:
- TA0006:T1110 # Brute Force
Tests:
- Name: SSO login failed
ExpectedResult: true
Log:
{
"id": "activity_01ABC123",
"created_at": "2026-05-05T21:33:29Z",
"organization_id": "org_01XYZ",
"type": "sso_login_failed",
"actor": {
"type": "unauthenticated_user_actor",
"ip_address": "192.168.1.1",
"user_agent": "Mozilla/5.0"
}
}
- Name: SSO login succeeded - not a match
ExpectedResult: false
Log:
{
"id": "activity_01DEF456",
"created_at": "2026-05-05T21:33:29Z",
"organization_id": "org_01XYZ",
"type": "sso_login_succeeded",
"actor": {
"type": "user_actor",
"email_address": "user@example.com",
"user_id": "user_01ABC",
"ip_address": "192.168.1.1"
}
}
Detection logic
Condition
type eq "sso_login_failed"
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 |
|---|---|---|
type | eq |
|
Output fields
Fields the rule emits when it matches. Chronicle authors list these in the outcome block; they appear on the detection and $risk_score drives alerting. Sentinel / Defender XDR rules build them up through project / summarize / extend stages. Sentinel maps these into alert fields via entityMappings and customDetails; Defender XDR custom detections surface them as alert fields directly.
| Field | Source |
|---|---|
event_type | type |
actor_type | actor.type |
actor_email | actor.email_address |
actor_user_id | actor.user_id |
ip_address | actor.ip_address |
user_agent | actor.user_agent |
api_key_id | actor.api_key_id |
organization_id | |
ips | p_any_ip_addresses |