Anthropic Organization User Deleted

Severity: informational
Group by: actor.email_address
Log types: Anthropic.Activity
Tags: Anthropic, Compliance, User Lifecycle
Source: github.com/panther-labs/panther-analysis

Tracks when a user is removed from the Anthropic organization. Logged for compliance visibility into user lifecycle changes. The deleted_user_id and deleted_user_email fields identify who was removed.

MITRE ATT&CK coverage

Tactic	Techniques
Impact	`T1531` Account Access Removal

Rule body yaml

AnalysisType: rule
RuleID: Anthropic.Activity.Org.User.Deleted
DisplayName: "Anthropic Organization User Deleted"
Enabled: true
Filename: anthropic_org_user_deleted.py
LogTypes:
  - Anthropic.Activity
Severity: Info
Description: >
  Tracks when a user is removed from the Anthropic organization. Logged
  for compliance visibility into user lifecycle changes. The deleted_user_id
  and deleted_user_email fields identify who was removed.
Runbook: |
  1. Find all Anthropic.Activity events by actor:email_address in the 6 hours before and after the alert to determine if this is part of routine offboarding or an isolated deletion
  2. Check if the deleted user had any unusual activity (claude_chat_access_failed, claude_organization_settings_updated) in the 7 days before removal
  3. Check if actor:email_address has deleted other users in the past 7 days to identify potential bulk unauthorized removals
Tags:
  - Anthropic
  - Compliance
  - User Lifecycle
Reports:
  MITRE ATT&CK:
    - TA0040:T1531  # Account Access Removal
Tests:
  - Name: Org user deleted
    ExpectedResult: true
    Log:
      {
        "id": "activity_01ABC123",
        "created_at": "2026-05-07T10:00:00Z",
        "organization_id": "org_01XYZ",
        "type": "org_user_deleted",
        "deleted_user_id": "user_01DEF",
        "deleted_user_email": "deleted-user@example.com",
        "actor": {
          "type": "user_actor",
          "email_address": "admin@example.com",
          "user_id": "user_01ABC",
          "ip_address": "10.0.0.1",
          "user_agent": "Mozilla/5.0"
        }
      }
  - Name: Non-matching event type
    ExpectedResult: false
    Log:
      {
        "id": "activity_01DEF456",
        "created_at": "2026-05-07T10:00:00Z",
        "organization_id": "org_01XYZ",
        "type": "org_user_invite_sent",
        "actor": {
          "type": "user_actor",
          "email_address": "admin@example.com",
          "user_id": "user_01ABC",
          "ip_address": "10.0.0.1"
        }
      }

Detection logic

Condition

type eq "org_user_deleted"

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	`org_user_deleted`

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`
`deleted_user_email`

`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)