--- title: "Binary Authorization - Santa Docs" description: "Binary Authorization - Open source binary authorization for macOS. Configure, deploy, and extend the agent that powers Workshop." doc_version: "1" last_updated: "2026-05-22" canonical: "https://northpole.security/docs/santa/features/binary-authorization" --- import AddedBadge from “@site/src/components/AddedBadge/AddedBadge”; # Binary Authorization Binary authorization, also known as binary allowlisting (and formerly, binary whitelisting) is a feature that lets Santa control which binaries are run on the same machine. This is a powerful control for both security and policy enforcement. ![Binary authorization notification dialog](https://northpole.security/docs/santa/img/binary-auth-dialog_dark.png) With Santa running, any time a binary is executed on the machine, Santa will decide whether the binary is allowed to be executed. - If the execution is allowed, everything will proceed as normal and Santa will cache its decision so that subsequent executions can avoid repetitive processing and execute faster. - If the execution is denied, Santa optionally presents a GUI notification over the top of any other windows detailing what was blocked. Santa supports multiple mechanisms for controlling which executables are allowed to run, with as little friction as possible. ## Rules The primary mechanism for deciding what is able to run is **Rules**. Rules can be synchronized from a server, configured statically in a profile, or managed locally with `santactl`. ### Rule Types Santa supports several different rule types and follows a strict evaluation order when determining which rule to enforce for a given execution. The following diagram shows Santa’s rule precedence: ``` flowchart TD Start(["Execution Attempt"]) --> RuleCDHash("Rule: **CDHash**") RuleCDHash --> RuleBinary("Rule: **BINARY**") RuleBinary --> RuleSigningID("Rule: **SIGNINGID**") RuleSigningID --> RuleCertificate("Rule: **CERTIFICATE**") RuleCertificate --> RuleTeamID("Rule: **TEAMID**") RuleTeamID --> Scope("**Scope**") Scope --> ClientMode("**Client Mode**") ClientMode --> End(["Decision"]) click RuleCDHash "#cdhash" click RuleBinary "#binary" click RuleSigningID "#signingid" click RuleCertificate "#certificate" click RuleTeamID "#teamid" click Scope "#scope" click ClientMode "#client-mode" ``` #### CDHash Value: `CDHASH` CDHash rules use a binary’s signed code directory hash as an identifier. This is the most specific rule in Santa. The code directory hash identifies a specific version of a program, similar to a file hash. Note that the operating system evaluates the CDHash lazily, only verifying pages of code when they’re mapped in. This means that it is possible for a file hash to change but a binary could still execute as long as modified pages are never mapped in. Santa only considers CDHash rules for processes that run under Apple’s [Hardened Runtime](https://developer.apple.com/documentation/security/hardened-runtime), to ensure that a process will be killed if the CDHash was tampered with (assuming the system has SIP enabled). #### Binary Value: `BINARY` Binary rules use the SHA-256 hash of the entire binary file as an identifier. This means that if the binary file is tampered with in any way then the rule will not match. #### SigningID Value: `SIGNINGID` Signing IDs are arbitrary identifiers under developer control that are given to a binary at signing time. Typically, these use reverse domain name notation and include the name of the binary (e.g. `com.google.Chrome`). Because the signing IDs are arbitrary, the Santa rule identifier must be prefixed with the Team ID associated with the Apple developer certificate used to sign the application. For example, a signing ID rule for Google Chrome would be: `EQHXZ8M8AV:com.google.Chrome`. For platform binaries (i.e. those binaries shipped by Apple with the OS) which do not have a Team ID, the string `platform` must be used (e.g. `platform:com.apple.curl`). The `santactl fileinfo` command can be used to help find this information: ``` » santactl fileinfo /Applications/Santa.app Path : /Applications/Santa.app/Contents/MacOS/Santa SHA-256 : 66acf5c808ddb86c10137b5ae4c72cd14985ed2f90e5850d8e26ab962cb93c70 SHA-1 : 259f6b0ffc9cccc069eab2aee1496f5a12072ee7 Bundle Name : Santa Bundle Version : 2025.3.97 Bundle Version Str : 2025.3 Team ID : ZMCG7MLDV9 # highlight-next-line Signing ID : ZMCG7MLDV9:com.northpolesec.santa CDHash : ea7c2330699c760b2d6c2c3e703fde01ca54e9b4 Type : Executable (arm64, x86_64) Code-signed : Yes Rule : Allowed (SigningID) ``` #### Certificate Value: `CERTIFICATE` Certificate rules are formed from the SHA-256 fingerprint of an X.509 leaf signing certificate. This is a powerful rule type that has a much broader reach than an individual binary rule. A signing certificate can sign any number of binaries. Allowing or blocking just a few key signing certificates can cover the bulk of an average user’s binaries. The leaf signing certificate is the only part of the chain that is evaluated. Though the whole chain is available for viewing. Santa does not evaluate the Valid From or Valid Until fields, nor does it check the Certificate Revocation List (CRL) or the Online Certificate Status Protocol (OCSP) for revoked certificates. Adding rules for the certificate chain’s intermediates or roots has no effect on binaries signed by a leaf. Santa ignores the chain and is only concerned with the leaf certificate’s SHA-256 hash. ``` » santactl fileinfo /Applications/Santa.app Path : /Applications/Santa.app/Contents/MacOS/Santa SHA-256 : 66acf5c808ddb86c10137b5ae4c72cd14985ed2f90e5850d8e26ab962cb93c70 SHA-1 : 259f6b0ffc9cccc069eab2aee1496f5a12072ee7 Bundle Name : Santa Bundle Version : 2025.3.97 Bundle Version Str : 2025.3 Team ID : ZMCG7MLDV9 Signing ID : ZMCG7MLDV9:com.northpolesec.santa CDHash : ea7c2330699c760b2d6c2c3e703fde01ca54e9b4 Type : Executable (arm64, x86_64) Code-signed : Yes Rule : Allowed (SigningID) Signing Chain: # highlight-next-line 1. SHA-256 : 1afd16f5b920f0d3b5f841aace6e948d6190ea8b5156b02deb36572d1d082f64 SHA-1 : 42890bc8a2a8becda00d63bdf9a89a6756a0da49 Common Name : Developer ID Application: North Pole Security, Inc. (ZMCG7MLDV9) Organization : North Pole Security, Inc. Organizational Unit : ZMCG7MLDV9 Valid From : 2024/10/11 21:24:15 -0400 Valid Until : 2027/02/01 17:12:15 -0500 2. SHA-256 : 7afc9d01a62f03a2de9637936d4afe68090d2de18d03f29c88cfb0b1ba63587f SHA-1 : 3b166c3b7dc4b751c9fe2afab9135641e388e186 Common Name : Developer ID Certification Authority Organization : Apple Inc. Organizational Unit : Apple Certification Authority Valid From : 2012/02/01 17:12:15 -0500 Valid Until : 2027/02/01 17:12:15 -0500 3. SHA-256 : b0b1730ecbc7ff4505142c49f1295e6eda6bcaed7e2c68c5be91b5a11001f024 SHA-1 : 611e5b662c593a08ff58d14ae22452d198df6c60 Common Name : Apple Root CA Organization : Apple Inc. Organizational Unit : Apple Certification Authority Valid From : 2006/04/25 17:40:36 -0400 Valid Until : 2035/02/09 16:40:36 -0500 ``` #### TeamID Value: `TEAMID` The Apple Developer Program Team ID is a 10-character identifier issued by Apple and tied to developer accounts/organizations. This is distinct from Certificates, as a single developer account can and frequently will request/rotate between multiple different signing certificates and entitlements. This is an even more powerful rule with broader reach than individual certificate rules and should be used with care. ``` » santactl fileinfo /Applications/Santa.app Path : /Applications/Santa.app/Contents/MacOS/Santa SHA-256 : 66acf5c808ddb86c10137b5ae4c72cd14985ed2f90e5850d8e26ab962cb93c70 SHA-1 : 259f6b0ffc9cccc069eab2aee1496f5a12072ee7 Bundle Name : Santa Bundle Version : 2025.3.97 Bundle Version Str : 2025.3 # highlight-next-line Team ID : ZMCG7MLDV9 Signing ID : ZMCG7MLDV9:com.northpolesec.santa CDHash : ea7c2330699c760b2d6c2c3e703fde01ca54e9b4 Type : Executable (arm64, x86_64) Code-signed : Yes Rule : Allowed (SigningID) ``` ### Policies Once a rule has been found that matches a given executable, the action to take is based on the policy attached to the rule. Santa supports several policies. #### Allowlist Value: `ALLOWLIST` The binary is allowed to execute and this decision is cached such that subsequent executions of the same binary will not be processed to increase performance. #### Allowlist Compiler Value: `ALLOWLIST_COMPILER` If Santa is configured to [enable transitive allowlisting](https://northpole.dev/configuration/keys#EnableTransitiveRules) then the binary is allowed to execute and any files that it writes will be read upon closing (or renamed) to check whether they are Mach-O binaries. When a Mach-O binary has been written by an allowed compiler, a transitive rule will be created for it that is valid for 6 months. This rule will allow that binary only on the machine that it was created on. The purpose of transitive allowlisting is to allow developers to live in Lockdown mode while still being able to do local development. Allowlisting the final process in a build toolchain (usually a linker or the `codesign` tool) will usually allow developers to work as normal. If transitive allowlisting is *not* enabled, the rule will be treated as if it were a regular Allowlist rule. #### Blocklist Value: `BLOCKLIST` The execution will be blocked. This will be the case even if the host is in Monitor or Standalone mode, and it will not be possible to override. Blocklist rules are intended to block applications that an organization deems to be malicious or against policy. Rules can have custom messages attached to them, which override the default message shown when Santa blocks an application. This can be used in Blocklist rules to inform users *why* a particular application is blocked. #### Silent Blocklist Value: `SILENT_BLOCKLIST` Silent Blocklist rules are identical to normal Blocklist rules but the GUI will not be displayed when such a rule is triggered. This rule type should be used sparingly. Blocking an application without informing the user that it was Santa that did it can be a *very* confusing experience for users and lead to wasted time trying to determine the underlying cause. #### CEL Value: `CEL` CEL (Common Expression Language) rules allow for more complex policies than would normally be possible. A rule with this policy must also include a valid [CEL expression](https://cel.dev/) which will be evaluated as part of making a decision. The input to the expression will be an [santa.cel.v1.ExecutionContext](https://github.com/northpolesec/protos/blob/2a1ccb8059dccea5b4b9f9a2be77a9810cb0184d/cel/v1.proto#L42) and the return value must either be a [santa.cel.v1.ReturnValue](https://github.com/northpolesec/protos/blob/2a1ccb8059dccea5b4b9f9a2be77a9810cb0184d/cel/v1.proto#L20) or a bool. If the return value is a bool, true will be treated as a `ReturnValue.ALLOWLIST` and false will be treated as `ReturnValue.BLOCKLIST`. The accessed fields in the `ExecutionContext` will determine whether the result of the expression can be cached. This is very important to be aware of, as overuse of CEL rules that prevent caching can have a negative impact on system performance, especially for binaries that are executed frequently. The following fields are available on the `target` object: Field Type Description `target.signing_id` `string` Signing ID of the target binary, prefixed with Team ID or `platform` (e.g. `EQHXZ8M8AV:com.google.Chrome` or `platform:com.apple.curl`) `target.signing_time` `timestamp` Code signing timestamp (developer-provided) `target.secure_signing_time` `timestamp` Secure code signing timestamp (from a timestamp authority) `target.is_platform_binary` `bool` Whether the binary is signed with Apple platform certificates `target.team_id` `string` Team ID from the binary’s code signature The following additional fields are available in the execution context: Field Type Description `path` `string` File path of the executable `args` `list` Command-line arguments passed to the binary `envs` `map` Environment variables available to the process `euid` `int` Effective user ID (0 for root, etc.) `cwd` `string` Current working directory of the process `ancestors` `list` Ancestor processes, ordered from the immediate parent at index `0` up to `launchd` at the end of the list. Only populated for [Workshop](https://northpole.security/) customers. Requires Santa 2026.2+ Each entry in `ancestors` has the following fields: Field Type Description `path` `string` File path of the ancestor’s executable `signing_id` `string` Signing ID of the ancestor, prefixed with Team ID or `platform` (e.g. `EQHXZ8M8AV:com.google.Chrome` or `platform:com.apple.bash`) `team_id` `string` Team ID from the ancestor’s code signature `cdhash` `string` Code directory hash of the ancestor `args` `list` Command-line arguments the ancestor was launched with. Requires Santa 2026.3+ Some examples of valid CEL expressions: ``` // Only allow executing versions of an app signed on or after May 31st 2025. // This expression will be cacheable. target.signing_time >= timestamp('2025-05-31T00:00:00Z') // Only allow Chrome from this team, block other apps. // Useful when attached to a TEAMID rule to allow a specific app. // This expression will be cacheable. target.signing_id.contains('com.google.Chrome') ? ALLOWLIST : BLOCKLIST // Prevent using the --inspect flag. // This expression will NOT be cacheable. '--inspect' in args ? BLOCKLIST : ALLOWLIST // Block all executions with DYLD_INSERT_LIBRARIES environment variable set. // This expression will NOT be cacheable. ! has(envs.DYLD_INSERT_LIBRARIES) // Only allow execution by non-root users. Requires Santa 2025.12+ euid != 0 // Disallow execution from inside /Library/LaunchDaemons. Requires Santa 2025.12+ cwd != '/Library/LaunchDaemons' // Only allow platform binaries from a specific path. // This expression will NOT be cacheable. target.is_platform_binary && path.startsWith('/usr/bin/') // Block executions whose immediate parent is Terminal. Requires Santa 2026.2+ // ancestors[0] is the immediate parent; the last entry is launchd. size(ancestors) > 0 && ancestors[0].path.endsWith('/Terminal') ? BLOCKLIST : ALLOWLIST ``` ### Rule Dictionary Format When defining rules in a plist (for StaticRules or import/export), each rule is represented as a dictionary with the following keys: #### Keys Key Type Required Description `identifier` String Yes The identifier for the rule. The format depends on the `rule_type` (see Identifier Format below). `policy` String Yes The action to take when the rule matches. See Supported Policies. `rule_type` String Yes The type of rule. See Rule Types for values. `custom_msg` String No A custom message displayed in the block notification when this rule blocks execution. `custom_url` String No A custom URL the user can visit for more information when blocked. Supports the same placeholders as [`EventDetailURL`](https://northpole.security/docs/santa/configuration/keys#EventDetailURL). `comment` String No A comment or note about the rule (for documentation purposes). `cel_expr` String No A CEL expression for the rule. **Required** if `policy` is `CEL`. #### Identifier Format The format of the `identifier` value depends on the `rule_type`: Rule Type Identifier Format Example `BINARY` SHA-256 hash (64 hex characters) `a1b2c3d4...` (64 chars) `CERTIFICATE` SHA-256 hash (64 hex characters) `a1b2c3d4...` (64 chars) `TEAMID` 10-character alphanumeric Team ID `EQHXZ8M8AV` `SIGNINGID` `TeamID:SigningID` format `EQHXZ8M8AV:com.google.Chrome` `CDHASH` Code Directory Hash (40 hex characters) `ea7c2330699c760b2d6c2c3e703fde01ca54e9b4` For `SIGNINGID` rules targeting platform binaries (those shipped with macOS), use `platform` as the Team ID prefix (e.g., `platform:com.apple.curl`). #### Supported Policies Value Description `ALLOWLIST` Allow execution `ALLOWLIST_COMPILER` Allow execution and enable transitive allowlisting (if configured) `BLOCKLIST` Block execution `SILENT_BLOCKLIST` Block execution without showing a notification `CEL` Evaluate a CEL expression to determine the action #### Example Rules Rules are typically provided either as part of the [`StaticRules`](https://northpole.security/docs/santa/configuration/keys#StaticRules) configuration key or from a sync server. Below are examples of individual rule dictionaries. **Block a specific binary by SHA-256 hash:** ``` identifier a1b2c3d4e5f6... rule_type BINARY policy BLOCKLIST custom_msg This application is not permitted by company policy. ``` **Allow all apps from a specific Team ID:** ``` identifier EQHXZ8M8AV rule_type TEAMID policy ALLOWLIST ``` **Allow a specific Signing ID:** ``` identifier EQHXZ8M8AV:com.google.Chrome rule_type SIGNINGID policy ALLOWLIST ``` **CEL rule to only allow recently signed versions:** ``` identifier EQHXZ8M8AV:com.google.Chrome rule_type SIGNINGID policy CEL cel_expr target.signing_time >= timestamp('2025-01-01T00:00:00Z') ``` When using `StaticRules`, these dictionaries are placed in an array under the `StaticRules` key in a configuration profile. When received from a sync server, the same structure is used but in JSON format. ## Rule Layering Since Santa is a first match system, there are some interesting ways you can layer rules to achieve different policies. For example if you want to allow all applications from a publisher (e.g. the Acme software company) you might start with an allow rule for the TeamID (ABCDEF1234) to allow all applications from that publisher. However if you then need to prevent a specific cloud-storage application written by the same provider, you can then use a higher precedence SigningID rule to block that company’s cloud storage product. Using `santactl` this would look like the following: ``` santactl rule --allow --teamid --identifier ABCDEF1234 santactl rule --block \ --signingid \ --identifier ABCDEF1234:com.acme-example.cloud-storage ``` You could also do the inverse and block everything by a publisher but allow a specific application by having a TeamID block rule and a SigningID allow rule. For example if you instead wanted to block everything from the Acme company except for the company’s cloud storage product you’d make a TeamID block rule for `ABCDEF1234` and a SigningID allow rule for the specific cloud storage product. Using `santactl` this would look like the following: ``` santactl rule --block --teamid --identifier ABCDEF1234 santactl rule --allow \ --signingid \ --identifier ABCDEF1234:com.acme-example.cloud-storage ``` ## Scope In addition to rules, Santa can allow or block based on scopes. Currently, only a few scopes are implemented. Scopes are evaluated after rules, with block evaluation preceding allow. Scope Allow/Block Configurable Description Blocked Path Regex Block [Yes](https://northpole.security/docs/santa/configuration/keys#BlockedPathRegex) A regex which the binary path is executed from is matched against. If the path matches the regex, the execution is blocked. Bad Signature Protection Block [Yes](https://northpole.security/docs/santa/configuration/keys#EnableBadSignatureProtection) If enabled, a binary that is executed with a bad signing chain will be blocked. Allowed Path Regex Allow [Yes](https://northpole.security/docs/santa/configuration/keys#AllowedPathRegex) A regex which the binary path is executed from is matched against. If the path matches the regex, the execution is allowed. Not a Mach-O Allow No Files which are not Mach-O binaries are ignored. ## Client Mode If Santa hasn’t made a decision based on existing Rules or due to a scope, the action that is taken depends on what mode Santa is running in. In event/telemetry output this is the `UNKNOWN` case: - Monitor: All unknown executions are allowed. - Lockdown: All unknown executions are blocked. - Standalone: All unknown executions are held until the user approves them, either by using TouchID or entering their password. If they approve the execution the execution is allowed to continue (without requiring re-execution) and a local SigningID or SHA-256 rule is automatically created. ## Sitemap - [Home](https://northpole.security/index.md) - [Workshop](https://northpole.security/workshop.md) - [Santa](https://northpole.security/santa.md) - [Features](https://northpole.security/features.md) - [Cookbook](https://northpole.security/cookbook.md) - [Docs](https://northpole.security/docs.md) - [Blog](https://northpole.security/blog.md) - [Glossary](https://northpole.security/glossary.md) - [About](https://northpole.security/about.md) - [Contact](https://northpole.security/contact.md)