AN1530: Analytic 1530
Monitors for anomalous binary files written to disk with padded size and subsequent execution by user or service context.
Analyst context for executives and security teams
AN1530 is a macOS detection analytic focused on binaries that are written to disk with anomalously padded file size and then executed by a user or service context. For leaders, the value is not the file-size detail itself; it is whether the organization can connect file creation evidence to later execution on macOS endpoints quickly enough to support containment, scoping, and audit-ready incident decisions.
Executive priority
Prioritize this analytic where macOS systems support sensitive users, privileged administration, software development, or business-critical operations. It tests a practical readiness question: can the security program prove when unusual binaries appear on disk and are subsequently run? If not, incident responders may lack the timeline needed to distinguish suspicious execution from normal software activity, increasing investigation time and business disruption.
Technical view
SOC and detection engineering teams should validate coverage for macOS file-write events involving binary files, file-size characteristics that indicate padding or unusual size, and subsequent process execution by the same or related user or service context. Because ATT&CK does not provide a tactic mapping or detailed detection logic for this analytic, teams should treat it as a behavioral correlation requirement rather than a complete rule. IR teams should ensure alerts preserve path, hash, size, signing/notarization context if locally available, parent process, user/service identity, and execution timestamp.
Likely telemetry
- macOS endpoint file creation or file modification events for binary files
- File metadata including path, size, hash, timestamps, and ownership
- Process execution telemetry on macOS
- User and service account context associated with file write and execution events
- Parent-child process relationships around the subsequent execution
Detection direction
- Validate that macOS telemetry can correlate a binary written to disk with later execution, not just detect one event independently.
- Tune for anomalous or padded file size relative to local software baselines; expect benign large or packaged software files to require allowlisting or context-based triage.
- Review false positives from installers, updaters, developer build outputs, security tools, and legitimate administrative scripts that write and execute binaries.
- Because no official detection logic is provided, define local thresholds and enrichment requirements before treating this as high-confidence malicious behavior.
- Confirm whether service-context execution is captured as reliably as interactive user execution, since gaps here can weaken coverage.
Mitigation priorities
- Establish baseline visibility for macOS file writes and process execution before relying on this analytic operationally.
- Apply application control, software trust, or execution policy controls where appropriate to reduce untrusted binary execution risk.
- Harden service account usage and review which services can write and execute binaries on macOS systems.
- Maintain response procedures for collecting file metadata, hashes, execution lineage, and user/service context when this analytic fires.
- Use the analytic as supporting evidence in incident response and compliance readiness, but do not treat padded size alone as proof of compromise.
Analyst notes and limits
This take is based only on the supplied ATT&CK analytic fields. The object describes a macOS analytic for anomalous padded binary files written to disk followed by execution. No tactics, relationships, aliases, or official detection implementation are supplied, so local environment baselines and telemetry validation are essential.
ATT&CK provides no relationship context, no tactic mapping, and no official detection logic for this object. The assessment cannot infer adversary attribution, active exploitation, specific malware, business impact, or guaranteed detection coverage. Applicability is limited to the supplied platform: macOS.
Analytic 1530
Monitors for anomalous binary files written to disk with padded size and subsequent execution by user or service context.
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 | 33aad41a99bc… |
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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[1]
mitre-attack AN1530Open source URL
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