Anthropic Excessive Chat Access Failures

Last updated 4 days ago on 2026-09-21
Created 13 days ago on 2026-09-12

About

Detects a single authenticated user generating an unusually high number of denied Claude chat access attempts in a 24-hour window. That pattern fits automated chat enumeration or attempts to reach conversations outside the actor's permissions. Unauthenticated shared-link actors lack user.id and are excluded.
Tags
Domain: GenAIPlatform: AnthropicData Source: Anthropic Audit LogsUse Case: Threat DetectionUse Case: UEBARule Type: ES|QLTactic: DiscoveryLanguage: esql
Severity
medium
Risk Score
47
MITRE ATT&CK™

Discovery (TA0007)(external, opens in a new tab or window)

False Positive Examples
Users browsing many stale or revoked shared chat links during incident response or legal review can produce bursts of access failures. Confirm whether the activity matches an approved investigation before escalating.
License
Elastic License v2(external, opens in a new tab or window)

Definition

Integration Pack
Prebuilt Security Detection Rules
Related Integrations

anthropic(external, opens in a new tab or window)

Query
text code block:
from logs-anthropic.audit-* | where data_stream.dataset == "anthropic.audit" and event.action == "claude_chat_access_failed" and user.id is not null | stats Esql.event_count = count(*), Esql.event_id_values = values(event.id), Esql.anthropic_audit_claude_chat_id_values = values(anthropic.audit.claude_chat_id), Esql.anthropic_audit_claude_project_id_values = values(anthropic.audit.claude_project_id), Esql.source_ip_values = values(source.ip), Esql.user_agent_original_values = values(user_agent.original), Esql.anthropic_audit_actor_type_values = values(anthropic.audit.actor.type), Esql.user_email_values = values(user.email), Esql.timestamp_first_seen = min(@timestamp), Esql.timestamp_last_seen = max(@timestamp) by user.id, organization.id, source.ip | where Esql.event_count >= 20 | keep user.id, organization.id, source.ip, Esql.*

Install detection rules in Elastic Security

Detect Anthropic Excessive Chat Access Failures in the Elastic Security detection engine by installing this rule into your Elastic Stack.

To setup this rule, check out the installation guide for Prebuilt Security Detection Rules(external, opens in a new tab or window).