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Potential Account Takeover - Logon from New Source IP

Identifies a user account that normally logs in with high volume from one source IP suddenly logging in from a different source IP. This pattern (one IP with many successful logons, another IP with very few) may indicate account takeover or use of stolen credentials from a new location.

Rule type: esql
Rule indices:

Rule Severity: medium
Risk Score: 47
Runs every: 15m
Searches indices from: now-30m
Maximum alerts per execution: 100
References:

Tags:

  • Domain: Endpoint
  • OS: Windows
  • Use Case: Threat Detection
  • Tactic: Privilege Escalation
  • Data Source: Windows Security Event Logs
  • Resources: Investigation Guide

Version: 1
Rule authors:

  • Elastic

Rule license: Elastic License v2

An account that historically logs in many times from a single source IP (e.g. usual workstation or VPN) and then shows successful logons from exactly one other IP with a low count may indicate credential compromise and use from a new location (account takeover).

  • Confirm with the account owner whether they recently logged in from the new source IP or from a new device/location.
  • Check the new source IP for reputation, geography, and whether it is expected (e.g. corporate VPN range vs unknown).
  • Correlate with other alerts for the same user or source IP (e.g. logon failures, password changes, MFA changes).
  • Review timeline: if the "new" IP logon is very recent compared to the high-count IP, treat as higher priority.
  • Legitimate use from a second device (e.g. new laptop, second office, VPN from travel) can produce exactly two IPs with one IP having few logons. Tune threshold (e.g. max_logon >= 100) or add exclusions for known VPN/remote ranges if needed.
  • Service or shared accounts that are used from multiple jump hosts or scripts may show two IPs; consider excluding known service accounts.
  • If takeover is confirmed: force password reset, revoke sessions, and enable or enforce MFA. Disable or lock the account until the user verifies identity.
  • Investigate how credentials may have been compromised (phishing, breach, endpoint) and address the vector.
from logs-system.security*, logs-windows.forwarded*, winlogbeat-* metadata _id, _version, _index
| where event.category == "authentication" and event.action == "logged-in" and winlog.event_id == "4624" and
        event.outcome == "success" and winlog.logon.type in ("Network", "RemoteInteractive") and
		source.ip is not null and source.ip != "127.0.0.1" and not to_string(source.ip) like "*::*" and not user.name like "*$"
| stats logon_count = COUNT(*) by user.name, source.ip
| stats
    Esql.max_logon = MAX(logon_count),
    Esql.min_logon = MIN(logon_count),
    Esql.source_ip_values = VALUES(source.ip),
    Esql.count_distinct = COUNT_DISTINCT(source.ip) by user.name

// high count of logons is often associated with service account tied to a specific source.ip, if observed in use from a new source.ip it's suspicious
| where Esql.max_logon >= 1000 and (Esql.min_logon >= 1 and Esql.min_logon <= 5) and Esql.count_distinct == 2
| eval source.ip = mv_first(Esql.source_ip_values)
| KEEP user.name, source.ip, Esql.*

Framework: MITRE ATT&CK