Application Execution Policy
Apply deny-by-exception (blacklisting) policy to prevent the use of unauthorized software or deny-all, permit-by-exception (whitelisting) policy to allow the execution of authorized software.
What gets scored, the objectives
CM.L2-3.4.8 is met only when every one of these 3 objectives, from NIST SP 800-171A, is satisfied. A single missed objective makes the whole requirement not met.
- a.a policy specifying whether whitelisting or blacklisting is to be implemented is specified
- b.the software allowed to execute under whitelisting or denied use under blacklisting is specified
- c.whitelisting to allow the execution of authorized software or blacklisting to prevent the use of unauthorized software is implemented as specified
How this is assessed
NIST SP 800-171A defines three assessment methods. For CM.L2-3.4.8, whoever assesses it, including your own team in a self assessment, uses these:
Configuration management policy; procedures addressing least functionality in the system; system security plan; configuration management plan; system design documentation; system configuration settings and associated documentation; list of software programs not authorized to execute on the system; list of software programs authorized to execute on the system; security configuration checklists; review and update records associated with list of authorized or unauthorized software programs; change control records; system audit logs and records; other relevant documents or records
Personnel with responsibilities for identifying software authorized or not authorized to execute on the system; personnel with information security responsibilities; system or network administrators
Organizational process for identifying, reviewing, and updating programs authorized or not authorized to execute on the system; process for implementing blacklisting or whitelisting; mechanisms supporting or implementing blacklisting or whitelisting
What it means, in context
The process used to identify software programs that are not authorized to execute on systems is commonly referred to as blacklisting . The process used to identify software programs that are authorized to execute on systems is commonly referred to as whitelisting. Whitelisting is the stronger of the two policies for restricting software program execution. In addition to whitelisting, organizations consider verifying the integrity of whitelisted software programs using, for example, cryptographic checksums, digital signatures, or hash functions. Verification of whitelisted software can occur either prior to execution or at system startup. NIST SP 800-167 provides guidance on application whitelisting.
Organizations should determine their blacklisting or whitelisting policy and configure the system to manage software that is allowed to run. Blacklisting or deny-by-exception allows all software to run except if on an unauthorized software list such as what is maintained in antivirus solutions. Whitelisting or permit-by-exception does not allow any software to run except if on an authorized software list. The stronger policy of the two is whitelisting. This requirement, CM.L2-3.4.8, requires the implementation of allow-lists and deny-lists for application software. It leverages CM.L2-3.4.1, which requires the organization to establish and maintain software inventories. This requirement, CM.L2-3.4.8, also extends CM.L2-3.4.9, which only requires c ontrol and monitoring of any user installed software. Example To improve your company’s protection from malware, you have decided to allow only designated programs to run. With additional research you identify a capability within the latest operating system that can control executables, scripts, libraries, or application installers run in your environment [c]. To ensure success you begin by authorizing digitally signed executables. Once they are deployed, you then plan to evaluate and deploy whitelisting for software libraries and scripts [c].
What passing evidence looks like
Your application execution policy (denylist or allowlist, stated), the named list of software you allow or deny under it, and the mechanism screenshot: AppLocker or WDAC rules, Intune policy, or the signed rule for tiny shops plus the standard user + no install rights model.
Common ways contractors fail CM.L2-3.4.8
- !Deny by exception (blacklisting) is acceptable at this requirement, an allowlist is stronger. Whichever you claim, the mechanism must exist somewhere technical, a paper rule alone is thin for a 5 pointer.
The step by step walkthrough for Microsoft 365 GCC High, Google Workspace, and on premises setups, plus the exact evidence to capture, lives inside the CMMC Level 2 plan.
Prove CM.L2-3.4.8, and the other 109
The Level 2 workspace walks your team through all 110 requirements at the objective level, drafts your SSP section by section from your own record for your team to read and accept, gives a prime or your own internal auditor a read only seat on the same record, and a credentialed officer reviews every step.
Book a free advisory callNo credit card, and Level 1 and Level 2 are both open, so sign up for the level your contracts call for. Self assessed and self attested: you score yourself in SPRS on a three year cycle and your senior official affirms it every year. As of September 3, 2026 a class deviation directs contracting officers to remove third party assessment from contracts. The program rule still provides for it, so your solicitation sets the track. Your team builds the same evidence either way. DFARS 252.204-7012 is unaffected, and the NIST SP 800-171 Rev 2 baseline is unchanged.
CM.L2-3.4.8 questions, answered
How many points is CMMC requirement CM.L2-3.4.8 worth?+
CM.L2-3.4.8 is worth 5 points in the CMMC Level 2 score under 32 CFR 170.24. If it is not met, you lose 5 from your total of 110.
Can CM.L2-3.4.8 be placed on a POA&M?+
No. CM.L2-3.4.8 must be fully met before you can file. It cannot be deferred to a POA&M, so it is a gate on your assessment.
What family does CM.L2-3.4.8 belong to?+
CM.L2-3.4.8 is in the Configuration Management (CM) family, one of the 14 families of NIST SP 800-171 that make up CMMC Level 2.
- NIST SP 800-171 Rev. 2 3.4.8