An allowlist, also known as a “whitelist,” is a cybersecurity term for a list of entities, items, or actions explicitly permitted or granted access within a specific context. It’s the opposite of a blocklist, also known as a “blacklist,” which contains entities, items, or actions that are explicitly denied or prohibited in a network.

You can compare an allowlist to the approved guest list of an exclusive event. If your name’s not on it, you won’t be allowed entry into the venue, regardless of who you are.

Read More about an Allowlist

An allowlist is especially useful in computer networks that require security or protection against hacking and other cyber threats.

What Are the Uses of an Allowlist?

Allowlists are employed in various security contexts. Companies use them in their computer networks, software, and online services to specify what they consider safe to access. We named a few sample uses below.

  • Network security: In network security, an allowlist can specify which Internet Protocol (IP) addresses or domains can connect to a system or service. Only connections from sources in the allowlist are permitted. All others are denied.
  • Software: In software, allowlists can define which executable files or scripts are permitted to run. That helps prevent the execution of potentially harmful or unauthorized programs within a network.
  • Email filtering: In email systems, an allowlist can ensure that only messages from specific addresses or domains are not marked as spam and delivered directly to their intended recipients’ inboxes.
  • Web browsing: Some web browsers or security software allow users to create allowlists containing links to trusted and safe-to-access websites, effectively blocking all others to enhance cybersecurity.

How Does an Allowlist Differ from a Blocklist?

An allowlist and a blocklist are two cybersecurity concepts used to control resource access, but they have opposite purposes and functions. Take a look at what these are.

In sum, an allowlist only permits approved entities, actions, or items, while a blocklist focuses on denying access to those considered unwanted or harmful. Both are used to enhance security by controlling access to resources and mitigating potential risks. It’s important to note, though, that the use of the terminologies may vary slightly depending on the context and industry.

Allowlist Versus Blocklist

What Are the Advantages of Using an Allowlist Than a Blocklist?

Using an allowlist over a blocklist provides several advantages regarding cybersecurity, resource management, and overall system control. Here are some of them.

  • Unknown threat mitigation: Allowlists can help protect against new and evolving threats that traditional blocklists may not yet cover. Since only approved actions are allowed, unknown or unauthorized ones are automatically blocked.
  • Maintenance effort reduction: Allowlists can often require less maintenance than blocklists, as new entities or actions must be explicitly approved, reducing the need to update and manage a long list of blocked entities constantly.
  • Regulatory compliance: In some industries or regulatory environments, it may be necessary to define what is allowed rather than explicitly blocked. Allowlists can help organizations demonstrate compliance more effectively.
  • User experience improvement: In situations where entities need access to resources, using an allowlist can ensure that authorized entities experience smoother and uninterrupted access, improving user satisfaction.
  • Resource abuse prevention: Allowlists can prevent unauthorized use or abuse of resources, such as bandwidth, processing power, or storage, by only permitting actions that have been explicitly approved.

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While allowlists offer many advantages, they may only be suitable for some situations. Some scenarios may require combining an allowlist and a blocklist to provide comprehensive security measures. Choosing between an allowlist or a blocklist often depends on an organization’s specific security requirements, risk tolerance, and operational needs.

Key Takeaways

  • An allowlist or whitelist contains entities, items, or actions explicitly permitted or granted access within specific contexts.
  • While an allowlist only permits approved entities, actions, or items access to resources, a blocklist denies access to those considered unwanted or harmful.
  • Also, while using allowlists mitigates unknown threats, requires little maintenance effort, ensures regulatory compliance, improves user experience, and prevents resource abuse, there are times when they should be used in combination with blocklists.