Attack Ent T1555 002 Securityd Memory

MITRE ATT&CK T1555.002: Securityd Memory

When to use this skill

Use this skill when the task involves T1555.002, Securityd Memory, 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: T1555.002
• Technique name: Securityd Memory
• Type: sub-technique
• ATT&CK URL: https://attack.mitre.org/techniques/T1555/002
• Tactics: credential-access
• Platforms: Linux, macOS
• Required permissions: Not specified
• Effective permissions: Not specified
• Defenses bypassed: Not specified

ATT&CK description

An adversary with root access may gather credentials by reading securityd’s memory. securityd is a service/daemon responsible for implementing security protocols such as encryption and authorization.(Citation: Apple Dev SecurityD) A privileged adversary may be able to scan through securityd's memory to find the correct sequence of keys to decrypt the user’s logon keychain. This may provide the adversary with various plaintext passwords, such as those for users, WiFi, mail, browsers, certificates, secure notes, etc.(Citation: OS X Keychain)(Citation: OSX Keydnap malware)

In OS X prior to El Capitan, users with root access can read plaintext keychain passwords of logged-in users because Apple’s keychain implementation allows these credentials to be cached so that users are not repeatedly prompted for passwords.(Citation: OS X Keychain)(Citation: External to DA, the OS X Way) Apple’s securityd utility takes the user’s logon password, encrypts it with PBKDF2, and stores this master key in memory. Apple also uses a set of keys and algorithms to encrypt the user’s password, but once the master key is found, an adversary need only iterate over the other values to unlock the final password.(Citation: OS X Keychain)

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:

• Keydnap (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.