/posh-secrets-scan

A script to check a git repo for secrets

Primary LanguagePowerShellOtherNOASSERTION

Secrets Scan

This is a powershell script that will scan a directory for secret violations. These can be RSA keys, AWS Access Keys, or any other type of secrets that may be present in code.

This will not prevent someone from checking them in to a git repository. The purpose is for CI, like jenkins, to execute the scan before the build process, and fail the build if there are secrets found.

If you would like to prevent the commit from even happening, you should look at git-secrets from awslabs. This is a git hook bash script to run on your local development environment. They have a very detailed readme to explain how to configure it.

NOTE: All the password, access keys, tokens, etc. located within this repository are made up from a random string generation

Mitigations

  • Mark false positives as allowed by adding exceptions to .secrets-scan.json
  • Revoke the Secret that was identified. The secret is no longer secure as it now exists in the commit history, even if removed from code.

Install

The way we run this scan is on a Jenkins Windows Build Agent. On the build agent, we have a specific directory to scripts. We have an environment variable ENV:SCRIPTS_PATH defined that contains that path.

Here is a sample build configuration for a job to scan a repository:

  • The first block makes sure the build agent has the latest version of the script installed.
  • It does this by downloading a script that exists in this repository and executes it.
  • The downloaded script will download the necessary files to the specified -Path argument, which is set to the ENV:SCRIPTS_PATH in the example below.
  • The second block executes the scan and returns based on the result of the scan.

Windows Powershell:

$scriptsPath = "$ENV:SCRIPTS_PATH";
$initScript = (New-Object System.Net.WebClient).DownloadString("https://raw.githubusercontent.com/SavoLabs/posh-secrets-scan/master/Secret-Scan-Initialize.ps1");
& $([scriptblock]::Create($initScript)) -Path $scriptsPath;

Windows Powershell:

(& powershell.exe -File "$ENV:SCRIPTS_PATH\secrets-scan.ps1" -Path "$ENV:WORKSPACE" -ConfigFile "$ENV:SCRIPTS_PATH\.secrets-scan.json");
exit $LASTEXITCODE;

Usage

PS> ./Secrets-Scan.ps1 -Path "C:\code\my-project\"

Rules are defined in .secrets-scan.json in the root directory of the Secrets-Scan.ps1. Additionally, a scanned directory can contain its own .secrets-scan.json that will be merged with the root configuration. See the Rules section below for more information.

Example of passing all parameters:

PS> ./Secrets-Scan.ps1 -Path "C:\code\my-project\" -ConfigFile ".\.secrets-scan.json" -Quiet

Parameters

Name Description Required Type Default
Path The path to scan ☑ String NULL
ConfigFile The path to the Rules file ☐ String ./.secrets-scan.json
Quiet If provided, no output will be logged ☐ Switch false

Scanning

Scanning will happen recursivly through the specified Path. It will scan all files, including files within hidden folders, and hidden files.

Additionally, if git is found within the $ENV:PATH, an attempt to get commit history logs for the last 4 commits, and those diffs will be scanned.

Voilations that are found within the commit history will be identified by having [Commit] and the commit SHA Hash. An example can be found below under Allowed.

To disable scanning of commit history, set commits: false in the .secrets-scan.json file.

Violations

The exit code of the script will be 0 for success, or it will be the count of the number of Violations found. The script will output the full path of the files that have violations, and the matching violation. Warnings will not change the exit code.

[Warning]: Found 1 Violation that was overridden by exception rules.
    [-] C:\code\my-project\super-secret-key.txt: AWS_ACCESS_KEY=wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY

[Error]: Found 5 Violations.
    [x] C:\code\my-project\super-secret-key.txt: AWS_SECRET_KEY=PnsrlQ4QaWqISJ5zcNkma1ClqHBshI0Y65mYwnNT
    [x] C:\code\my-project\super-secret-key.txt: AWS_ACCESS_KEY=RtwpOEp4IeQqHawn7hsBIC13Cap2qCt1AmQqIOMY
		[x] C:\code\my-project\Subfolder\more-secrets.txt: aws_account_id:129398745743
		[x] C:\code\my-project\Subfolder\more-secrets.txt: [Commit]cd79426d236bf31f21933e0dd6cb604cb2958fd2: aws_account_id:129398745743
    [x] C:\code\my-project\Subfolder\my-key.pem: -----BEGIN RSA PRIVATE KEY-----


Possible mitigations:
    - Mark false positives as allowed by adding exceptions to '.secrets-scan.json'
    - Revoke the Secret that was identified. The secret is no longer secure as it
        now exists in the commit history, even if removed from code.

Rules

Rules are defined in .secrets-scan.json. In there, you define the matching patterns, and the allowed exceptions. Both patterns and allowed sections are arrays of regex patterns.

Pattern

This matches on the text in the file.

Allowed

This matches on the file name and the violation match.

/path/to/file.ext: VIOLATION_MATCH

Voilations that are identified within a git commit history will have [Commit]<COMMIT-SHA>: in the violation like the following:

/path/to/file.ext: [Commit]cd79426d236bf31f21933e0dd6cb604cb2958fd2: VIOLATION_MATCH

Ideally, only basic exceptions should be defined in the main .secrets-scan.json, other exceptions would be defined in a file, also called .secrets-scan.json, within the root directory of the repository to be scanned. The script will load, and merge, the 2 configurations together.

{
	"patterns": [
		"(?msi)(\"|')?(aws)?_?(secret)?_?(access)?_?(key)(\"|')?\\s*(:|=>|=)\\s*(\"|')?([a-z0-9/\\+=]{40}|[a-z0-9/\\+=]{20})(\"|')?",
		"(?msi)(?:key\\s*=\\s*)(?:\"|')?((?:aws)?_?(?:secret)?_?(?:access)?_?(?:key))(?:\"|')?\\s*(?:value\\s*=\\s*)(?:\"|')?([a-z0-9/\\+=]{40}|[a-z0-9/\\+=]{20})(?:\"|')?",
		"(?msi)(\"|')?((?:aws)?_?(?:account)_?(?:id)?)(\"|')?\\s*(:|=>|=)\\s*(\"|')?[0-9]{4}\\-?[0-9]{4}\\-?[0-9]{4}(\"|')?",
		"(?msi)(?:key\\s*=\\s*)(?:\"|')?((?:aws)?_?(?:account)_?(?:id)?)(?:\"|')?\\s*(?:value\\s*=\\s*)(?:\"|')?([0-9]{4}\\-?[0-9]{4}\\-?[0-9]{4})(?:\"|')?",
		"(?msi)-{5}begin\\s[rd]sa\\sprivate\\skey-{5}",
		"(?msi)\\[?(?:\"|'|:)?(p(?:ass)?w(?:or)?d)(?:\"|'|:)?\\]?\\s*(:|=>|=)\\s*(?:\"|')?([\\w\\s\\d\\-*\/~`!@\\#\\$%\\^&\\(\\)_\\<\\>;\\.,\\?\\$\"']+)(?:\"|'|)?"
	],
	"allowed": [
		"AKIAIOSFODNN7EXAMPLE",
		"wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY"
	],
	"commits": true
}