# Attack Ent T1564 005 Hidden File System > Analyze MITRE ATT&CK T1564.005 Hidden File System in the enterprise matrix. Use for TTP triage, detection engineering, hunting, defensive emulation planning, mitigations, incident response mapping, ATT&CK coverage, or questions mentioning T1564.005, Hidden File System, or enterprise ATT&CK. Adversaries may use a hidden file system to conceal malicious activity from users and security tools. - Skill: `santosomar/attack-ent-t1564-005-hidden-file-system` (Agent Skill, multi-file: 11 files) - Install (CLI): `npx skillmds@latest add santosomar/attack-ent-t1564-005-hidden-file-system` - Raw SKILL.md: https://api.skillmd.com/api/skills/santosomar/attack-ent-t1564-005-hidden-file-system/raw - Safety review: pending - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Security - License: MITRE ATT&CK Terms of Use apply to ATT&CK-derived content. See h - Author: santosomar (https://skillmd.com/u/santosomar) - Updated: 2026-09-22 - Page: https://skillmd.com/skills/santosomar/attack-ent-t1564-005-hidden-file-system --- # MITRE ATT&CK T1564.005: Hidden File System ## When to use this skill Use this skill when the task involves T1564.005, Hidden File System, enterprise ATT&CK, TTP mapping, detection engineering, hunting, incident-response enrichment, control validation, or authorized adversary-emulation planning. Treat it as a defensive analysis aid: keep outputs focused on understanding, detecting, mitigating, and safely validating this ATT&CK sub-technique. ## Technique context - ATT&CK domain: enterprise - ATT&CK ID: T1564.005 - Technique name: Hidden File System - Type: sub-technique - ATT&CK URL: https://attack.mitre.org/techniques/T1564/005 - Tactics: stealth - Platforms: Linux, macOS, Windows - Required permissions: Not specified - Effective permissions: Not specified - Defenses bypassed: Not specified ## ATT&CK description Adversaries may use a hidden file system to conceal malicious activity from users and security tools. File systems provide a structure to store and access data from physical storage. Typically, a user engages with a file system through applications that allow them to access files and directories, which are an abstraction from their physical location (ex: disk sector). Standard file systems include FAT, NTFS, ext4, and APFS. File systems can also contain other structures, such as the Volume Boot Record (VBR) and Master File Table (MFT) in NTFS.(Citation: MalwareTech VFS Nov 2014) Adversaries may use their own abstracted file system, separate from the standard file system present on the infected system. In doing so, adversaries can hide the presence of malicious components and file input/output from security tools. Hidden file systems, sometimes referred to as virtual file systems, can be implemented in numerous ways. One implementation would be to store a file system in reserved disk space unused by disk structures or standard file system partitions.(Citation: MalwareTech VFS Nov 2014)(Citation: FireEye Bootkits) Another implementation could be for an adversary to drop their own portable partition image as a file on top of the standard file system.(Citation: ESET ComRAT May 2020) Adversaries may also fragment files across the existing file system structure in non-standard ways.(Citation: Kaspersky Equation QA) ## Agent workflow 1. Clarify scope: identify the system, asset class, log sources, cloud or endpoint platform, and whether the user wants triage, detection, coverage assessment, or safe emulation planning. 2. Load bundled resources as needed: use `references/technique-profile.json` for structured metadata, `references/detection-and-mitigation.md` for triage and telemetry guidance, `references/known-threat-context.md` for ATT&CK relationship context, and `templates/` for repeatable outputs. 3. Map observations to ATT&CK: compare the user's evidence to the ATT&CK description, tactics, platforms, and known procedure patterns before asserting a match. 4. Produce defensive outputs: prioritize hypotheses, telemetry requirements, detection logic ideas, validation steps, containment guidance, and mitigations. 5. Preserve uncertainty: distinguish confirmed evidence, plausible indicators, assumptions, and gaps. Recommend what to collect next. 6. Stay safe: do not provide malware, credential theft, persistence, evasion, destructive automation, or unauthorized exploitation instructions. For adversary emulation, keep steps bounded to approved lab or control-validation contexts and omit operational abuse details. ## Bundled resources - `references/technique-profile.json`: machine-readable ATT&CK metadata for this technique. - `references/detection-and-mitigation.md`: detection notes, telemetry checklist, triage questions, mitigation candidates, and false-positive considerations. - `references/known-threat-context.md`: ATT&CK relationship context with attribution cautions. - `templates/detection-brief.md`: detection engineering brief template. - `templates/hunt-plan.md`: threat hunt plan template. - `templates/incident-response-note.md`: incident response note template. - `templates/coverage-assessment.md`: ATT&CK coverage assessment template. - `scripts/render_brief.py`: local helper that renders a Markdown defensive brief from `technique-profile.json`. - `assets/output-schema.json`: JSON schema for structured technique analysis outputs. To generate a quick brief, run `python scripts/render_brief.py --output brief.md` from inside this skill directory, or adapt the templates directly. ## Detection guidance No ATT&CK detection guidance was present in the source STIX object. ## Useful telemetry and data sources - Not specified in the STIX object. ## Mitigations to consider - No ATT&CK mitigation relationships were present in the source STIX bundle. ## Known threat context Use these examples only as contextual leads, not as proof that an observed event is this technique: - BOOTRASH (malware) - ComRAT (malware) - Equation (intrusion-set) - Regin (malware) - Strider (intrusion-set) - Uroburos (malware) ## Recommended output pattern When responding with this skill, structure the answer as: - Assessment: whether the evidence supports this ATT&CK mapping and why. - Evidence: specific indicators, logs, behaviors, and assumptions. - Detection: telemetry sources, analytic logic, and tuning considerations. - Response: containment, eradication, recovery, and validation actions. - Coverage gaps: missing logs, sensors, controls, or environmental details. - References: include the ATT&CK URL and any user-provided evidence references.