AN1521: Analytic 1521
Series of authentication failures (Event ID 4625) targeting the same or similar user accounts over time from one or more remote IPs
Analyst context for executives and security teams
This analytic matters because repeated Windows authentication failures against the same or similar user accounts can be an early warning that an identity-based attack is in progress or that legitimate access is breaking in a way that could affect operations. For leaders, the decision value is whether the organization can reliably see failed logons, connect them to source IPs and target accounts over time, and escalate suspicious patterns before account lockouts, service disruption, or incident response uncertainty grows.
Executive priority
Prioritize this as an identity and SOC readiness validation item. Executives should ask whether Windows failed-logon evidence is centrally collected, retained long enough for trend analysis, and reviewed in a way that distinguishes normal user error from repeated remote targeting. This supports incident decision-making, audit evidence around access monitoring, and control prioritization for authentication monitoring.
Technical view
For Windows environments, validate monitoring for Event ID 4625 patterns where repeated authentication failures target the same or similar user accounts over time from one or more remote IP addresses. Because no ATT&CK tactic, technique relationship, or official detection logic is supplied, teams should treat this as a detection analytic concept rather than a complete rule. SOC and detection engineers should define thresholds, time windows, account-similarity logic, and source-IP grouping based on local authentication patterns.
Likely telemetry
- Windows Security Event Log authentication failure events, specifically Event ID 4625
- Target user account names associated with failed logons
- Source network address or remote IP fields from authentication events
- Timestamps sufficient to identify repeated failures over time
- Host or domain controller context where the failed authentication was recorded
Detection direction
- Confirm Event ID 4625 is collected from the Windows systems or authentication points that matter to the environment.
- Correlate repeated failures by target account, similar account naming patterns, source IP, and time window.
- Tune thresholds to reduce noise from password mistakes, expired credentials, service account misconfiguration, and scheduled jobs using old passwords.
- Review whether NAT, VPN, proxies, or incomplete source-IP logging could hide the true origin of repeated failures.
- Because no relationship context is supplied, do not assume a specific ATT&CK technique; use this analytic as a starting point for identity anomaly triage.
Mitigation priorities
- Ensure centralized collection and retention of Windows failed-authentication logs.
- Validate account lockout, password, and authentication monitoring policies are aligned with business tolerance for disruption and investigation needs.
- Review exposed or remotely reachable authentication paths and confirm they are monitored.
- Establish SOC triage procedures for repeated failures against one account, similar accounts, or many accounts from related remote IPs.
- Use incident response playbooks to distinguish misconfiguration from suspicious remote authentication activity before taking disruptive containment actions.
Analyst notes and limits
The supplied object is a detection analytic for Windows authentication failures, not a full ATT&CK technique entry. Its practical value is in validating identity telemetry coverage and correlation logic for repeated failed logons. Local baselines are important because failed authentication events can be common in normal operations.
The official detection field is not provided, tactics are not specified, and no relationship context is supplied. This take cannot infer attribution, active exploitation, specific impact, or guaranteed detection coverage. Thresholds, severity, and response actions require environment-specific evidence.
Analytic 1521
Series of authentication failures (Event ID 4625) targeting the same or similar user accounts over time from one or more remote IPs
How security teams should use this page
Treat this object as behavior context, not an attribution claim. Validate the related groups, software, data sources, and mitigations against official ATT&CK relationships and your own telemetry before making control-coverage decisions.
All related ATT&CK context
No relationships are available in the current normalized data for this object.
Object version and sync metadata
The fields below describe the current mirrored snapshot. When Glexia retains multiple ATT&CK source imports, you can open the table to compare the same object across releases (hashes and MITRE timestamps). For MITRE’s own release notes and roadmap, see ATT&CK resources — Updates .
Imported snapshots across ATT&CK releases (1)
| Release | Bundle imported | Object version | Modified | Status | Raw hash |
|---|---|---|---|---|---|
| 19.1 | 1.0 | Current bundle | 3c27f343e23e… |
Mirrored ATT&CK source object
The raw object is retained through the mirrored ATT&CK source bundle and object hash. The raw endpoint returns the exact object from the mirrored bundle when available.
External references and citations
MITRE external references are preserved separately from Glexia analysis so citations remain traceable to their original source records.
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mitre-attack AN1521Open source URL
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