10.4 | Analyzing source code | Languages | Secrets

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Secrets are pieces of user-specific or system-level credentials that should be protected and accessible to legitimate users only. SonarQube detects exposed Secrets in all files processed by the language analyzers and in all files configured through the sonar.text.inclusions property.

Secrets analysis is available starting in Community Edition.

Language-specific properties

Discover and update the Secrets-specific properties in Administration > Configuration > General Settings > Languages > Secrets. 

Defining custom secret patterns

The custom secret patterns feature is available starting in Enterprise Edition.

In order to detect secrets that are specific to your company, you can define custom rules based on your own secret patterns. 

In a given custom rule, the secret detection is specified as follows:

  • The secret patterns to detect are defined through regular expressions. A context can be added to restrict the matching.
  • Specific files can be excluded from the secret detection based on the file name or content. This allows improving the detection accuracy and time.
  • Obvious false-positive matches can be excluded from the detection results.

The main steps to create a custom rule are: 

  1. Define and test the regular expressions matching the secrets to detect. 
  2. Specify the rule’s secret detection in YAML format.
  3. Create the corresponding secret detection rule in SonarQube and add it to your quality profile for secrets.

These steps are described below.

Define the regular expressions matching the secrets to detect

Define and validate the regular expression(s) matching the secrets to be detected by your custom rule. 

To build, test, and debug regular expressions, we recommend that you use https://regex101.com/

In addition, you can apply the Sonar’s rules dedicated to regular expressions to your regular expressions to make sure there are no mistakes and no performance problems, and possibly to find out a simpler way to write the same regular expression. To do so, proceed as follows:

Step 1: Create a small Java project (since the secret detection feature uses Java) and put your regular expressions into it. In the project example below, replace CustomRegExpExample with your regular expression.

import java.util.regex.Pattern;

public class CustomSecretRegExpCheck {
    public static void main(String[] args) {
        CustomSecretRegExpCheck checker = new CustomSecretRegExpCheck();
        final String INPUT = "Hello, World!";

        System.out.println("Result: " + checker.isMatchingCustomRegExpExample(INPUT));

    public boolean isMatchingCustomRegExpExample(String input) {
        Pattern pattern = Pattern.compile("CustomRegExpExample.*");
        return pattern.matcher(input).find();

Step 2: Run a SonarQube analysis on your project. Note that if you use an IDE running SonarLint, you will get immediate feedback and this step is not necessary.

Specify the rule’s secret detection in YAML format

You must specify the secret detection in YAML format according to the Detection section of this schema. This section consists of three subsections:

  • pre: Defines the files to be excluded from the secret detection based on file name or content.
  • matching: Contains the regular expressions used to detect the secrets. 
  • post: Defines the obvious false-positive to be excluded from the matching candidates. 

Examples of the matching subsection

To match a string corresponding to MyCustomSecret_123, a minimal configuration would be :

  pattern: "MyCustomSecret_\\d{3}"

You can also restrict the detection to particular contexts. For example, if you want to detect MyCustomSecret_123 only if:

  • either preceded by beforeContext 
  • or followed by afterContext

Then, you could use the following matching configuration:

  pattern: "MyCustomSecret_\\d{3}"
      - patternBefore: "beforeContext"
      - patternAfter: "afterContext"

Create the corresponding secret detection rule in SonarQube

You can now create the corresponding custom rule in SonarQube. To do so, you'll create an instance of the rule template S6784: User-specified secrets should not be disclosed.

Proceed as follows:

Step 1: In the top navigation bar of SonarQube, click Rules.

Step 2: Set the rule search filter as follows:

    1. In the Language option, select Secrets.
    2. In the Template option, click Show Templates Only

Step 3: In the search results, click the User-specified secrets should not be disclosed rule.

Step 4: At the bottom of the rule page, in the Custom Rules section, click Create. The Create Custom Rule dialog opens.

Step 5: Fill in the rule parameter fields:

    • Name: Rule title.
      We recommend making it very explicit about the service, department, and in-house application.
      Example: AppXZY tokens should not be disclosed
    • Key: Unique identifier of the rule.
      We recommend following a naming convention to make it easier to retrieve your custom secrets.
    • Type: Rule type. Default (recommended): Vulnerability.
    • Severity: Rule severity. Default (recommended): Blocker.
    • Status: Rule status. Default (recommended): Ready.
    • Description: Rule description. The description should be as detailed as possible in order to allow the developer to know what to do in case of a secret detection. In this field, you can describe the procedure to be followed in your company for such cases.
    • DetectionSpecification: Copy and paste into this field the specification you created in the Specify the rule’s secret detection in YAML format step as illustrated below.

Step 6: Click Create. The dialog closes and the new rule is created.

Step 7: Add the new rule to the quality profile that you use for secrets: see Quality Profiles. If you don’t already have a custom quality profile for secrets, you must create one (to do so, it’s strongly recommended to extend the Sonar way.). 

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