Definition
Blocking the execution of files on a host in accordance with defined application policy rules.
How it works
Criteria
A policy-enforcing application can register an application for denylisting based on conditions including the following:
This may be done to prevent execution of applications which are:
System administrators will customize the rules for the given environment.
- File attributes
- file name
- file path
- file hash
- file publisher, as obtained from the digital signature
- permissions of the file
- File malware scan (eg. Windows SmartScreen)
- User-File combination
- an old version with known vulnerabilities
- without a valid license, which could cause legal issues
- in a directory that is accessible to low-privileged users, that could be accessed by a malware dropper
- known trojan horse programs
- too open in their permissions, possibly set to run as a user other than the originator or allowing execution when they should not be
- a match to the hash of other known malware
- are detected as undesirable based on a file scan runtime behavior
Backend
The policy-enforcing program may work by running in kernel mode, and [intercepting] [system calls which execute a process].
Considerations
- If denylisting is done by filename, filepath, or hash, these mechanisms may be a worthy first line of defense and detection, but could still be evaded by an attacker.
- Continuous management is needed to keep the denylist up to date, whether it is based on hash, publisher, behavior, or any other digital artifact.
- Although denylists based on attributes such as file path and virus scan could defend against some threats which they have not been explicitly coded to block, denylists may not provide protection from new, unknown, or zero day attacks.
Examples
On a Windows machine the Windows Defender Application Control (WDAC) policy enforcement is run in the kernel and allows for restricting applications.
Implementation perspective
Executable Denylisting should be treated as a technical defensive capability rather than a product checkbox. In practice, teams should define the protected scope, the conditions under which the technique acts, and the observable evidence that demonstrates the intended behavior. For this technique, likely engineering context includes Create Process, Executable File.
Use the technique to create a logical or physical boundary that limits access, execution, communication, or movement.
Questions to ask
- What is being isolated, from whom or what, and under which conditions?
- Which flows or operations remain explicitly allowed across the boundary?
- What happens when the isolation mechanism fails or loses policy context?
- How is the boundary tested for alternate paths, bypasses, and unintended dependencies?
Evidence and validation
- Architecture and data-flow diagrams showing the isolation boundary
- Policy, rule, or configuration exports from enforcing components
- Tests of allowed, denied, and failure-state behavior
- Monitoring evidence for boundary violations and policy changes
Common failure patterns
- The intended boundary has undocumented alternate paths or inherited trust relationships.
- Rules accumulate without ownership, review, or removal of obsolete exceptions.
- Isolation is assumed from network location while application, identity, or management paths remain open.
This implementation perspective is original Bare Metal Cyber educational content. It does not replace the official D3FEND definition or establish that a specific product implements the technique.
Technique hierarchy
Top-level family
Parent techniques
Direct child techniques
None listed at this level.
Artifacts and ontology entities
These relationships describe how D3FEND connects a defensive technique to artifacts or other ontology entities. They describe graph semantics, not a product certification.
Explicit technique relationships
Show inferred artifact relationship paths (2)
NIST SP 800-53 relationships
The relation label is preserved from the D3FEND ontology. It is not converted into a claim that the control automatically implements or validates this technique.
ATT&CK Enterprise mitigation relationships
These links come from the D3FEND ontology’s ATT&CK mitigation mapping. They help users navigate between the knowledge bases and do not guarantee mitigation effectiveness.
Offensive-technique relationships
These relationships are generated from D3FEND graph paths and are explicitly experimental. They should be treated as hypotheses for defensive analysis—not as proof that the technique prevents, detects, or removes an offensive behavior.
ATT&CK Enterprise (51)
ATT&CK for ICS (7)
Authoritative sources
- Open this technique on the official D3FEND website ↗
- Open the official ontology resources ↗
- Content extractor and analysis system ↗Bit 9 Inc, Carbon Black Inc · Todd Brennan · PatentReference
- Method and apparatus for increasing the speed at which computer viruses are detected ↗McAfee LLC · Paul D. Cozza · PatentReference
Bare Metal Cyber is an independent educational publisher and is not affiliated with or endorsed by The MITRE Corporation. MITRE D3FEND™ and the D3FEND logo are trademarks of The MITRE Corporation. MITRE ATT&CK® and ATT&CK® are registered trademarks of The MITRE Corporation. Use of D3FEND source material is subject to the official Terms of Use.