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Defining custom patterns for secret scanning

You can extend secret scanning to detect secrets beyond the default patterns.

Secret scanning is available for organization-owned repositories in GitHub AE. This is a GitHub Advanced Security feature (free during the beta release).

About custom patterns for secret scanning

You can define custom patterns to identify secrets that are not detected by the default patterns supported by secret scanning. For example, you might have a secret pattern that is internal to your organization. For details of the supported secrets and service providers, see "Secret scanning patterns."

You can define custom patterns for your enterprise, organization, or repository. Secret scanning supports up to 100 custom patterns for each organization or enterprise account, and 20 per repository.

Regular expression syntax for custom patterns

You can specify custom patterns for secret scanning as one or more regular expressions.

  • Secret format: an expression that describes the format of the secret itself.
  • Before secret: an expression that describes the characters that come before the secret. By default, this is set to \A|[^0-9A-Za-z] which means that the secret must be at the start of a line or be preceded by a non-alphanumeric character.
  • After secret: an expression that describes the characters that come after the secret. By default, this is set to \z|[^0-9A-Za-z] which means that the secret must be followed by a new line or a non-alphanumeric character.
  • Additional match requirements: one or more optional expressions that the secret itself must or must not match.

For simple tokens you will usually only need to specify a secret format. The other fields provide flexibility so that you can specify more complex secrets without creating complex regular expressions. For an example of a custom pattern, see "Example of a custom pattern specified using additional requirements" below.

Secret scanning uses the Hyperscan library and only supports Hyperscan regex constructs, which are a subset of PCRE syntax. Hyperscan option modifiers are not supported. For more information on Hyperscan pattern constructs, see "Pattern support" in the Hyperscan documentation.

Defining a custom pattern for a repository

Before defining a custom pattern, you must ensure that secret scanning is enabled on your repository. For more information, see "Configuring secret scanning for your repositories."

  1. No your enterprise, navegue até a página principal do repositório.

  2. Abaixo do nome do repositório, clique em Configurações. Botão Configurações do repositório

  3. In the left sidebar, click Security & analysis. "Security & analysis" tab in repository settings

  4. Em "Segurança e análise de código", encontre o "GitHub Advanced Security".

  5. Em "Secret scanning", em "Padrões personalizados", clique em Novo padrão.

  6. Enter the details for your new custom pattern:

    1. You must at least provide the name for your pattern, and a regular expression for the format of your secret pattern.
    2. You can click More options to provide other surrounding content or additional match requirements for the secret format.
    3. Provide a sample test string to make sure your configuration is matching the patterns you expect.

    Create a custom secret scanning pattern form

  7. When you're satisfied with your new custom pattern, click Create pattern.

After your pattern is created, secret scanning verifica todos segredos em todo o histórico do Git em todos os branches presentes no repositório GitHub. For more information on viewing secret scanning alerts, see "Managing alerts from secret scanning."

Example of a custom pattern specified using additional requirements

A company has an internal token with five characteristics. They use the different fields to specify how to identify tokens as follows:

CharacteristicField and regular expression
Length between 5 and 10 charactersSecret format: [$#%@AA-Za-z0-9]{5,10}
Does not end in a .After secret: [^\.]
Contains numbers and uppercase lettersAdditional requirements: secret must match [A-Z] and [0-9]
Does not include more than one lowercase letter in a rowAdditional requirements: secret must not match [a-z]{2,}
Contains one of $%@!Additional requirements: secret must match [$%@!]

These tokens would match the custom pattern described above:

a9@AAfT!         # Secret string match: a9@AAfT
ee95GG@ZA942@aa  # Secret string match: @ZA942@a
a9@AA!ee9        # Secret string match: a9@AA

These strings would not match the custom pattern described above:

a9@AA.!
a@AAAAA
aa9@AA!ee9
aAAAe9

Defining a custom pattern for an organization

Before defining a custom pattern, you must ensure that you enable secret scanning for the repositories that you want to scan in your organization. To enable secret scanning on all repositories in your organization, see "Managing security and analysis settings for your organization."

Note: As there is no dry-run functionality, we recommend that you test your custom patterns in a repository before defining them for your entire organization. That way, you can avoid creating excess false-positive secret scanning alerts.

  1. No canto superior direito do GitHub AE, clique na foto do seu perfil e clique em Suas organizações. Suas organizações no menu de perfil

  2. Ao lado da organização, clique em Configurações. Botão de configurações

  3. In the left sidebar, click Security & analysis. "Security & analysis" tab in organization settings

  4. Em "Segurança e análise de código", encontre o "GitHub Advanced Security".

  5. Em "Secret scanning", em "Padrões personalizados", clique em Novo padrão.

  6. Enter the details for your new custom pattern:

    1. You must at least provide the name for your pattern, and a regular expression for the format of your secret pattern.
    2. You can click More options to provide other surrounding content or additional match requirements for the secret format.
    3. Provide a sample test string to make sure your configuration is matching the patterns you expect.

    Create a custom secret scanning pattern form

  7. When you're satisfied with your new custom pattern, click Create pattern.

After your pattern is created, secret scanning scans for any secrets in repositories in your organization, including their entire Git history on all branches. Organization owners and repository administrators will be alerted to any secrets found and can review the alert in the repository where the secret is found. For more information on viewing secret scanning alerts, see "Managing alerts from secret scanning."

Defining a custom pattern for an enterprise account

Note: As there is no dry-run functionality, we recommend that you test your custom patterns in a repository before defining them for your entire enterprise. That way, you can avoid creating excess false-positive secret scanning alerts.

  1. No canto superior à direita de GitHub AE, clique na foto do perfil e clique em Configurações da empresa. "Configurações da empresa" no menu suspenso da foto do perfil em GitHub AE

  2. Na barra lateral da empresa, clique em Políticas. Guia Políticas na barra lateral da conta corporativa

  3. Em Políticas, clique em "Segurança Avançada". Políticas de "Segurança Avançada" na barra lateral

  4. Em "GitHub Advanced Security", clique na guia Recursos de segurança.

  5. Under "Secret scanning custom patterns", click New pattern.

  6. Enter the details for your new custom pattern:

    1. You must at least provide the name for your pattern, and a regular expression for the format of your secret pattern.
    2. You can click More options to provide other surrounding content or additional match requirements for the secret format.
    3. Provide a sample test string to make sure your configuration is matching the patterns you expect.

    Create a custom secret scanning pattern form

  7. When you're satisfied with your new custom pattern, click Create pattern.

After your pattern is created, secret scanning scans for any secrets in repositories within your enterprise's organizations with GitHub Advanced Security enabled, including their entire Git history on all branches. Organization owners and repository administrators will be alerted to any secrets found, and can review the alert in the repository where the secret is found. For more information on viewing secret scanning alerts, see "Managing alerts from secret scanning."

Editing a custom pattern

When you save a change to a custom pattern, this closes all the secret scanning alerts that were created using the previous version of the pattern.

  1. Navigate to where the custom pattern was created. A custom pattern can be created in a repository, organization, or enterprise account.
  2. Under "Secret scanning", to the right of the custom pattern you want to edit, click .
  3. When you have reviewed and tested your changes, click Save changes.

Removing a custom pattern

  1. Navigate to where the custom pattern was created. A custom pattern can be created in a repository, organization, or enterprise account.

  2. To the right of the custom pattern you want to remove, click .

  3. Review the confirmation, and select a method for dealing with any open alerts relating to the custom pattern.

  4. Click Yes, delete this pattern.

    Confirming deletion of a custom secret scanning pattern