What is application allowlisting?

What is allowlisting?

In today’s cybersecurity landscape, blocking malware and untrusted software demands more than reactive antivirus measures. Application allowlisting - where only trusted software is permitted to run - offers a robust “default-deny” security posture.

Application allowlisting ensures that only trusted applications can execute on a device. idemeum’s agent intercepts every process launch - if an application lacks an explicit allow rule, execution is denied. This proactive “zero trust for executables” model blocks ransomware, unknown software, and lateral movement. Unlike blocklists that try to catch bad actors, allowlisting denies all by default and grants access only to verified software - drastically reducing the attack surface.

Allowlisting vs. Blocklisting

Although “application allowlisting” and “application whitelisting” refer to the same thing, application allowlisting is the preferred language for describing this security capability. According to the UK’s National Cyber Security Centre, equating “white” with “good, permitted, and safe” and black with “bad, dangerous, and forbidden” is problematic, especially when another less ambiguous term is available to describe the same activities.

It is the same case for “blocklisting” (or denylisting) and “blacklisting.” While using the term “blacklisting” to describe undesirable attributes in cybersecurity was common, the neutral “blocklisting” is now in favor.

Using a predefined list of “bad” applications, blocklisting software typically compares any applications attempting to run on the network with the list of blocked applications. If the application is not on the blocklist, it is allowed to proceed. For example, conventional antivirus software uses blocklisting to prevent known malware from being executed on a computer system. Since application allowlisting denies unlisted applications and application blocklisting allows unlisted applications, application allowlisting is arguably more secure than application blocklisting.

Which application control approach aligns with Zero Trust?

Application control can take one of two approaches, allowlisting or blocklisting. Although both seek to place some control over the applications in an environment, only allowlisting truly aligns with the Zero Trust "never trust, always verify" philosophy. In other words, nothing can be explicitly trusted, and every person, application, and network connection must be restricted to only the exact access they require. According to CISA (Cybersecurity and Infrastructure Security Agency) #StopRansomware Guide update published in May 2023, "Use allowlisting rather than attempting to list and deny every possible permutation of applications in a network environment."

Use cases

• Ransomware defense: block unknown binaries and scripts from executing - even if they’re downloaded by a trusted process.

• Regulatory compliance: enforce strict control for HIPAA, PCI-DSS, and NIST standards.

• Least privilege access: combine with Endpoint Privilege Management (EPM) to remove admin rights while keeping teams productive.

• Audit : get full visibility into what’s executed across your fleet - instantly and historically.

Idemeum allowlisting

Traditional allowlisting approaches are known for being rigid, hard to manage, and generate a lot of operational load for IT / MSP teams. This is where idemeum brings innovation: a simple, intelligent, and scalable solution that makes allowlisting practical for real-world use.

Default deny with OS trust

• Idemeum automatically trusts essential Windows system binaries (OSBinary), ensuring no disruption to core operations.

• At the same time, it blocks signed but dangerous executables like mshta.exe or powershell.exe - often exploited in fileless attacks.

Powerful and flexible rule engine

• Define rules by file path, filename, SHA-256 hash, publisher certificate, or regex patterns.

• Match criteria using certificate metadata like Common Name (CN), Organization (O), and Organizational Unit (OU).

One-click catalog rules

• idemeum provides a pre-built catalog of trusted applications like Slack, Notepad, Zoom, and more.

• These rules are kept up to date and can be applied instantly to reduce manual effort.

Real-time audit and event-based rules

• Every MSI and EXE execution is logged and uploaded to the cloud within minutes.

• Admins can view these events and generate allow/deny rules directly from the UI - closing the loop on what users are running.

Integrated privilege management

• idemeum’s allowlisting integrates tightly with Endpoint Privilege Management (EPM).

• A single rule can allow execution and elevate privileges without granting full local admin access - bridging the gap between security and usability.

Child process trust inheritance

• When a trusted app launches a subprocess, trust can be inherited automatically.

• This prevents legitimate parent-child application chains (e.g., an installer launching a helper binary) from breaking.

Application fencing controls

• Go beyond allowlisting - control what allowed apps can do.

• Prevent Office apps from launching PowerShell, block browsers from spawning command shells, and isolate potentially risky behaviors.

Conclusion

Application allowlisting is one of the most powerful defenses against modern threats - but only if it’s implemented in a way that works for both security and operations. idemeum gets it right by combining real-time visibility, flexible policy control, and intelligent defaults.

With integrated privilege management, catalog rules, and fine-grained process control, idemeum modernizes allowlisting into a scalable, cloud-native capability fit for the Zero Trust era.