# Attack Ent T1056 004 Credential API Hooking

> Analyze MITRE ATT&CK T1056.004 Credential API Hooking in the enterprise matrix. Use for TTP triage, detection engineering, hunting, defensive emulation planning, mitigations, incident response mapping, ATT&CK coverage, or questions mentioning T1056.004, Credential API Hooking, or enterprise ATT&CK. Adversaries may hook into Windows application programming interface (API) functions and Linux system functions to collect user credentials.

- Skill: `santosomar/attack-ent-t1056-004-credential-api-hooking` (Agent Skill, multi-file: 11 files)
- Install (CLI): `npx skillmds@latest add santosomar/attack-ent-t1056-004-credential-api-hooking`
- Raw SKILL.md: https://api.skillmd.com/api/skills/santosomar/attack-ent-t1056-004-credential-api-hooking/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Integrations & APIs
- 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-t1056-004-credential-api-hooking

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# MITRE ATT&CK T1056.004: Credential API Hooking

## When to use this skill

Use this skill when the task involves T1056.004, Credential API Hooking, 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: T1056.004
- Technique name: Credential API Hooking
- Type: sub-technique
- ATT&CK URL: https://attack.mitre.org/techniques/T1056/004
- Tactics: collection, credential-access
- Platforms: Windows, Linux, macOS
- Required permissions: Not specified
- Effective permissions: Not specified
- Defenses bypassed: Not specified

## ATT&CK description

Adversaries may hook into Windows application programming interface (API) functions and Linux system functions to collect user credentials. Malicious hooking mechanisms may capture API or function calls that include parameters that reveal user authentication credentials.(Citation: Microsoft TrojanSpy:Win32/Ursnif.gen!I Sept 2017) Unlike [Keylogging](https://attack.mitre.org/techniques/T1056/001), this technique focuses specifically on API functions that include parameters that reveal user credentials. 

In Windows, hooking involves redirecting calls to these functions and can be implemented via:

* **Hooks procedures**, which intercept and execute designated code in response to events such as messages, keystrokes, and mouse inputs.(Citation: Microsoft Hook Overview)(Citation: Elastic Process Injection July 2017)
* **Import address table (IAT) hooking**, which use modifications to a process’s IAT, where pointers to imported API functions are stored.(Citation: Elastic Process Injection July 2017)(Citation: Adlice Software IAT Hooks Oct 2014)(Citation: MWRInfoSecurity Dynamic Hooking 2015)
* **Inline hooking**, which overwrites the first bytes in an API function to redirect code flow.(Citation: Elastic Process Injection July 2017)(Citation: HighTech Bridge Inline Hooking Sept 2011)(Citation: MWRInfoSecurity Dynamic Hooking 2015)

In Linux and macOS, adversaries may hook into system functions via the `LD_PRELOAD` (Linux) or `DYLD_INSERT_LIBRARIES` (macOS) environment variables, which enables loading shared libraries into a program’s address space. For example, an adversary may capture credentials by hooking into the `libc read` function leveraged by SSH or SCP.(Citation: Intezer Symbiote 2022)

## 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:

- Carberp (malware)
- Empire (tool)
- FinFisher (malware)
- NOKKI (malware)
- PLATINUM (intrusion-set)
- RDFSNIFFER (malware)
- TrickBot (malware)
- Ursnif (malware)
- VersaMem (malware)
- Zebrocy (malware)
- Zeus Panda (malware)
- ZxShell (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.