Defining custom patterns for secret scanning

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 20 custom patterns for each organization or enterprise account, and 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. On your GitHub Enterprise Server instance, navigate to the main page of the repository.

2. リポジトリ名の下の [ 設定] をクリックします。

3. In the left sidebar, click Security & analysis.

4. [コードのセキュリティと分析] の下で、「GitHub Advanced Security」を見つけてく� さい。

5. [Secret scanning] の [カスタ�  パターン] で、 [新しいカスタ�  パターン] をクリックします。

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.

   

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

After your pattern is created, secret scanningはGitHubリポジトリ中に存在するすべてのブランチのGit履歴全体に対して、あらゆるシークレットをスキャンします。 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:

Characteristic	Field and regular expression
Length between 5 and 10 characters	Secret format: [$#%@AA-Za-z0-9]{5,10}
Does not end in a .	After secret: [^\.]
Contains numbers and uppercase letters	Additional requirements: secret must match [A-Z] and [0-9]
Does not include more than one lowercase letter in a row	Additional 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."

1. GitHub Enterprise Server の右上隅にあるプロファイル写真をクリックし、 [自分の Organization] をクリックします。

2. 組織の隣の [設定] をクリックします。

3. In the left sidebar, click Security & analysis.

4. [コードのセキュリティと分析] の下で、「GitHub Advanced Security」を見つけてく� さい。

5. [Secret scanning] の [カスタ�  パターン] で、 [新しいカスタ�  パターン] をクリックします。

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.

   

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

Before defining a custom pattern, you must ensure that you enable secret scanning for your enterprise account. For more information, see "Enabling GitHub Advanced Security for your enterprise."

1. GitHub Enterprise Server の右上で、ご自分のプロファイル写真をクリックしてから、 [Enterprise 設定] をクリックします。

2. Enterprise サイドバーで、 [ポリシー] をクリックします。

3. [ ポリシー] で、[Advanced Security] をクリックします。

4. [GitHub Advanced Security] の [セキュリティ機能] タブをクリックします。

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

   

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

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.

   • For a repository or organization, display the "Security & analysis" settings for the repository or organization where the custom pattern was created. For more information, see "Defining a custom pattern for a repository" or "Defining a custom pattern for an organization" above.
   • For an enterprise, under "Policies" display the "Advanced Security" area, and then click Security features. For more information, see "Defining a custom pattern for an enterprise account" above.

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

3. Review the confirmation, and click Remove custom pattern.