An enterprise friendly way of detecting and preventing secrets in code.

detect-secrets

About

detect-secrets is an aptly named module for (surprise, surprise) detecting secrets within a code base.

However, unlike other similar packages that solely focus on finding secrets, this package is designed with the enterprise client in mind: providing a backwards compatible, systematic means of:

1. Preventing new secrets from entering the code base,
2. Detecting if such preventions are explicitly bypassed, and
3. Providing a checklist of secrets to roll, and migrate off to a more secure storage.

This way, you create a separation of concern: accepting that there may currently be secrets hiding in your large repository (this is what we refer to as a baseline), but preventing this issue from getting any larger, without dealing with the potentially gargantuous effort of moving existing secrets away.

It does this by running periodic diff outputs against heuristically crafted regex statements, to identify whether any new secret has been committed. This way, it avoids the overhead of digging through all git history, as well as the need to scan the entire repository every time.

For a look at recent changes, please see CHANGELOG.md.

If you are looking to contribute, please see CONTRIBUTING.md.

For more detailed documentation, check out our other documentation.

Examples

Quickstart:

Create a baseline of potential secrets currently found in your git repository.

$ detect-secrets scan > .secrets.baseline

Scanning non-git tracked files:

$ detect-secrets scan test_data/ --all-files > .secrets.baseline

Adding New Secrets to Baseline:

This will rescan your codebase, and:

1. Update/upgrade your baseline to be compatible with the latest version,
2. Add any new secrets it finds to your baseline,
3. Remove any secrets no longer in your codebase

This will also preserve any labelled secrets you have.

$ detect-secrets scan --baseline .secrets.baseline

For baselines older than version 0.9, just recreate it.

Alerting off newly added secrets:

Scanning Staged Files Only:

$ detect-secrets-hook --baseline .secrets.baseline $(git diff --staged --name-only)

Scanning All Tracked Files:

$ detect-secrets-hook --baseline .secrets.baseline $(git ls-files)

Viewing All Enabled Plugins:

$ detect-secrets scan --list-all-plugins
ArtifactoryDetector
AWSKeyDetector
AzureStorageKeyDetector
BasicAuthDetector
CloudantDetector
Base64HighEntropyString
HexHighEntropyString
IbmCloudIamDetector
IbmCosHmacDetector
JwtTokenDetector
KeywordDetector
MailchimpDetector
NpmDetector
PrivateKeyDetector
SlackDetector
SoftlayerDetector
StripeDetector
TwilioKeyDetector

Disabling Plugins:

$ detect-secrets scan --disable-plugin KeywordDetector --disable-plugin AWSKeyDetector

If you want to only run a specific plugin, you can do:

$ detect-secrets scan --list-all-plugins | \
    grep -v 'BasicAuthDetector' | \
    sed "s#^#--disable-plugin #g" | \
    xargs detect-secrets scan test_data

Auditing a Baseline:

This is an optional step to label the results in your baseline. It can be used to narrow down your checklist of secrets to migrate, or to better configure your plugins to improve its signal-to-noise ratio.

$ detect-secrets audit .secrets.baseline

Usage in Other Python Scripts

Basic Use:

from detect_secrets import SecretsCollection
from detect_secrets.settings import default_settings

secrets = SecretsCollection()
with default_settings():
    secrets.scan_file('test_data/config.ini')


import json
print(json.dumps(secrets.json(), indent=2))

More Advanced Configuration:

from detect_secrets import SecretsCollection
from detect_secrets.settings import transient_settings

secrets = SecretsCollection()
with transient_settings({
    # Only run scans with only these plugins.
    # This format is the same as the one that is saved in the generated baseline.
    'plugins_used': [
        # Example of configuring a built-in plugin
        {
            'name': 'Base64HighEntropyString',
            'limit': 5.0,
        },

        # Example of using a custom plugin
        {
            'name': 'HippoDetector',
            'path': 'file:///Users/aaronloo/Documents/github/detect-secrets/testing/plugins.py',
        },
    ],

    # We can also specify whichever additional filters we want.
    # This is an example of using the function `is_identified_by_ML_model` within the
    # local file `./private-filters/example.py`.
    'filters_used': [
        {
            'path': 'file://private-filters/example.py::is_identified_by_ML_model',
        },
    ]
}) as settings:
    # If we want to make any further adjustments to the created settings object (e.g.
    # disabling default filters), we can do so as such.
    settings.disable_filters(
        'detect_secrets.filters.heuristic.is_prefixed_with_dollar_sign',
        'detect_secrets.filters.heuristic.is_likely_id_string',
    )

    secrets.scan_file('test_data/config.ini')

Installation

$ pip install detect-secrets
✨🍰✨

Usage

detect-secrets comes with three different tools, and there is often confusion around which one to use. Use this handy checklist to help you decide:

1. Do you want to add secrets to your baseline? If so, use detect-secrets scan.
2. Do you want to alert off new secrets not in the baseline? If so, use detect-secrets-hook.
3. Are you analyzing the baseline itself? If so, use detect-secrets audit.

Adding Secrets to Baseline

$ detect-secrets scan --help
usage: detect-secrets scan [-h] [--string [STRING]] [--only-allowlisted]
                           [--all-files] [--baseline FILENAME]
                           [--force-use-all-plugins] [--slim]
                           [--list-all-plugins] [-p PLUGIN]
                           [--base64-limit [BASE64_LIMIT]]
                           [--hex-limit [HEX_LIMIT]]
                           [--disable-plugin DISABLE_PLUGIN]
                           [-n | --only-verified]
                           [--exclude-lines EXCLUDE_LINES]
                           [--exclude-files EXCLUDE_FILES]
                           [--exclude-secrets EXCLUDE_SECRETS]
                           [--word-list WORD_LIST_FILE] [-f FILTER]
                           [--disable-filter DISABLE_FILTER]
                           [path [path ...]]

Scans a repository for secrets in code. The generated output is compatible
with `detect-secrets-hook --baseline`.

positional arguments:
  path                  Scans the entire codebase and outputs a snapshot of
                        currently identified secrets.

optional arguments:
  -h, --help            show this help message and exit
  --string [STRING]     Scans an individual string, and displays configured
                        plugins' verdict.
  --only-allowlisted    Only scans the lines that are flagged with `allowlist
                        secret`. This helps verify that individual exceptions
                        are indeed non-secrets.

scan options:
  --all-files           Scan all files recursively (as compared to only
                        scanning git tracked files).
  --baseline FILENAME   If provided, will update existing baseline by
                        importing settings from it.
  --force-use-all-plugins
                        If a baseline is provided, detect-secrets will default
                        to loading the plugins specified by that baseline.
                        However, this may also mean it doesn't perform the
                        scan with the latest plugins. If this flag is
                        provided, it will always use the latest plugins
  --slim                Slim baselines are created with the intention of
                        minimizing differences between commits. However, they
                        are not compatible with the `audit` functionality, and
                        slim baselines will need to be remade to be audited.

plugin options:
  Configure settings for each secret scanning ruleset. By default, all
  plugins are enabled unless explicitly disabled.

  --list-all-plugins    Lists all plugins that will be used for the scan.
  -p PLUGIN, --plugin PLUGIN
                        Specify path to custom secret detector plugin.
  --base64-limit [BASE64_LIMIT]
                        Sets the entropy limit for high entropy strings. Value
                        must be between 0.0 and 8.0, defaults to 4.5.
  --hex-limit [HEX_LIMIT]
                        Sets the entropy limit for high entropy strings. Value
                        must be between 0.0 and 8.0, defaults to 3.0.
  --disable-plugin DISABLE_PLUGIN
                        Plugin class names to disable. e.g.
                        Base64HighEntropyString

filter options:
  Configure settings for filtering out secrets after they are flagged by the
  engine.

  -n, --no-verify       Disables additional verification of secrets via
                        network call.
  --only-verified       Only flags secrets that can be verified.
  --exclude-lines EXCLUDE_LINES
                        If lines match this regex, it will be ignored.
  --exclude-files EXCLUDE_FILES
                        If filenames match this regex, it will be ignored.
  --exclude-secrets EXCLUDE_SECRETS
                        If secrets match this regex, it will be ignored.
  --word-list WORD_LIST_FILE
                        Text file with a list of words, if a secret contains a
                        word in the list we ignore it.
  -f FILTER, --filter FILTER
                        Specify path to custom filter. May be a python module
                        path (e.g.
                        detect_secrets.filters.common.is_invalid_file) or a
                        local file path (e.g.
                        file://path/to/file.py::function_name).
  --disable-filter DISABLE_FILTER
                        Specify filter to disable. e.g.
                        detect_secrets.filters.common.is_invalid_file

Blocking Secrets not in Baseline

$ detect-secrets-hook --help
usage: detect-secrets-hook [-h] [-v] [--version] [--baseline FILENAME]
                           [--list-all-plugins] [-p PLUGIN]
                           [--base64-limit [BASE64_LIMIT]]
                           [--hex-limit [HEX_LIMIT]]
                           [--disable-plugin DISABLE_PLUGIN]
                           [-n | --only-verified]
                           [--exclude-lines EXCLUDE_LINES]
                           [--exclude-files EXCLUDE_FILES]
                           [--exclude-secrets EXCLUDE_SECRETS]
                           [--word-list WORD_LIST_FILE] [-f FILTER]
                           [--disable-filter DISABLE_FILTER]
                           [filenames [filenames ...]]

positional arguments:
  filenames             Filenames to check.

optional arguments:
  -h, --help            show this help message and exit
  -v, --verbose         Verbose mode.
  --version             Display version information.
  --baseline FILENAME   Explicitly ignore secrets through a baseline generated
                        by `detect-secrets scan`

plugin options:
  Configure settings for each secret scanning ruleset. By default, all
  plugins are enabled unless explicitly disabled.

  --list-all-plugins    Lists all plugins that will be used for the scan.
  -p PLUGIN, --plugin PLUGIN
                        Specify path to custom secret detector plugin.
  --base64-limit [BASE64_LIMIT]
                        Sets the entropy limit for high entropy strings. Value
                        must be between 0.0 and 8.0, defaults to 4.5.
  --hex-limit [HEX_LIMIT]
                        Sets the entropy limit for high entropy strings. Value
                        must be between 0.0 and 8.0, defaults to 3.0.
  --disable-plugin DISABLE_PLUGIN
                        Plugin class names to disable. e.g.
                        Base64HighEntropyString

filter options:
  Configure settings for filtering out secrets after they are flagged by the
  engine.

  -n, --no-verify       Disables additional verification of secrets via
                        network call.
  --only-verified       Only flags secrets that can be verified.
  --exclude-lines EXCLUDE_LINES
                        If lines match this regex, it will be ignored.
  --exclude-files EXCLUDE_FILES
                        If filenames match this regex, it will be ignored.
  --exclude-secrets EXCLUDE_SECRETS
                        If secrets match this regex, it will be ignored.
  -f FILTER, --filter FILTER
                        Specify path to custom filter. May be a python module
                        path (e.g.
                        detect_secrets.filters.common.is_invalid_file) or a
                        local file path (e.g.
                        file://path/to/file.py::function_name).
  --disable-filter DISABLE_FILTER
                        Specify filter to disable. e.g.
                        detect_secrets.filters.common.is_invalid_file

We recommend setting this up as a pre-commit hook. One way to do this is by using the pre-commit framework:

# .pre-commit-config.yaml
repos:
-   repo: https://github.com/Yelp/detect-secrets
    rev: v1.0.0
    hooks:
    -   id: detect-secrets
        args: ['--baseline', '.secrets.baseline']
        exclude: package.lock.json

Inline Allowlisting

There are times when we want to exclude a false positive from blocking a commit, without creating a baseline to do so. You can do so by adding a comment as such:

secret = "hunter2"      # pragma: allowlist secret

or

//  pragma: allowlist nextline secret
const secret = "hunter2";

Auditing Secrets in Baseline

$ detect-secrets audit --help
usage: detect-secrets audit [-h] [--diff] [--stats] [--json]
                            filename [filename ...]

Auditing a baseline allows analysts to label results, and optimize plugins for
the highest signal-to-noise ratio for their environment.

positional arguments:
  filename    Audit a given baseline file to distinguish the difference
              between false and true positives.

optional arguments:
  -h, --help  show this help message and exit
  --diff      Allows the comparison of two baseline files, in order to
              effectively distinguish the difference between various plugin
              configurations.
  --stats     Displays the results of an interactive auditing session which
              have been saved to a baseline file.

analytics:
  Quantify the success of your plugins based on the labelled results in your
  baseline. To be used with the statisitcs mode (--stats).

  --json      Outputs results in a machine-readable format.

Configuration

This tool operates through a system of plugins and filters.

• Plugins find secrets in code
• Filters ignore false positives to increase scanning precision

You can adjust both to suit your precision/recall needs.

Plugins

There are three different strategies we employ to try and find secrets in code:

1. Regex-based Rules

   These are the most common type of plugin, and work well with well-structured secrets. These secrets can optionally be verified, which increases scanning precision. However, solely depending on these may negatively affect the recall of your scan.

2. Entropy Detector

   This searches for “secret-looking” strings through a variety of heuristical approaches. This is great for non-structured secrets, but may require tuning to adjust the scanning precision.

3. Keyword Detector

   This ignores the secret value, and searches for variable names that are often associated with assigning secrets with hard-coded values. This is great for “non-secret-looking” strings (e.g. le3tc0de passwords), but may require tuning filters to adjust the scanning precision.

Want to find a secret that we don’t currently catch? You can also (easily) develop your own plugin, and use it with the engine! For more information, check out the plugin documentation.

Filters

detect-secrets comes with several different in-built filters that may suit your needs.

–exclude-lines

Sometimes, you want to be able to globally allow certain lines in your scan, if they match a specific pattern. You can specify a regex rule as such:

$ detect-secrets scan --exclude-lines 'password = (blah|fake)'

Or you can specify multiple regex rules as such:

$ detect-secrets scan --exclude-lines 'password = blah' --exclude-lines 'password = fake'

–exclude-files

Sometimes, you want to be able to ignore certain files in your scan. You can specify a regex pattern to do so, and if the filename meets this regex pattern, it will not be scanned:

$ detect-secrets scan --exclude-files '.*\.signature$'

Or you can specify multiple regex patterns as such:

$ detect-secrets scan --exclude-files '.*\.signature$' --exclude-files '.*/i18n/.*'

–exclude-secrets

Sometimes, you want to be able to ignore certain secret values in your scan. You can specify a regex rule as such:

$ detect-secrets scan --exclude-secrets '(fakesecret|\${.*})'

Or you can specify multiple regex rules as such:

$ detect-secrets scan --exclude-secrets 'fakesecret' --exclude-secrets '\${.*})'

Inline Allowlisting

Sometimes, you want to apply an exclusion to a specific line, rather than globally excluding it. You can do so with inline allowlisting as such:

API_KEY = 'this-will-ordinarily-be-detected-by-a-plugin'    # pragma: allowlist secret

These comments are supported in multiple languages. e.g.

const GoogleCredentialPassword = "something-secret-here";     //  pragma: allowlist secret

You can also use:

# pragma: allowlist nextline secret
API_KEY = 'WillAlsoBeIgnored'

This may be a convenient way for you to ignore secrets, without needing to regenerate the entire baseline again. If you need to explicitly search for these allowlisted secrets, you can also do:

$ detect-secrets scan --only-allowlisted

Want to write more custom logic to filter out false positives? Check out how to do this in our filters documentation.

Extensions

wordlist

The --exclude-secrets flag allows you to specify regex rules to exclude secret values. However, if you want to specify a large list of words instead, you can use the --word-list flag.

To use this feature, be sure to install the pyahocorasick package, or simply use:

$ pip install detect-secrets[word_list]

Then, you can use it as such:

$ cat wordlist.txt
not-a-real-secret
$ cat sample.ini
password = not-a-real-secret

# Will show results
$ detect-secrets scan sample.ini

# No results found
$ detect-secrets scan --word-list wordlist.txt

Gibberish Detector

The Gibberish Detector is a simple ML model, that attempts to determine whether a secret value is actually gibberish, with the assumption that real secret values are not word-like.

To use this feature, be sure to install the gibberish-detector package, or use:

$ pip install detect-secrets[gibberish]

Check out the gibberish-detector package for more information on how to train the model. A pre-trained model (seeded by processing RFCs) will be included for easy use.

You can also specify your own model as such:

$ detect-secrets scan --gibberish-model custom.model

This is not a default plugin, given that this will ignore secrets such as password.

Caveats

This is not meant to be a sure-fire solution to prevent secrets from entering the codebase. Only proper developer education can truly do that. This pre-commit hook merely implements several heuristics to try and prevent obvious cases of committing secrets.

Things That Won’t Be Prevented:

• Multi-line secrets
• Default passwords that don’t trigger the KeywordDetector (e.g. login = "hunter2")

FAQ

General

• “Did not detect git repository.” warning encountered, even though I’m in a git repo.

  Check to see whether your git version is >= 1.8.5. If not, please upgrade it then try again. More details here.

Windows

• detect-secrets audit displays “Not a valid baseline file!” after creating baseline.

  Ensure the file encoding of your baseline file is UTF-8. More details here.