Contents
git secrets --scan [-r|--recursive] [--cached] [--no-index] [--untracked] [<files>...] git secrets --scan-history git secrets --install [-f|--force] [<target-directory>] git secrets --list [--global] git secrets --add [-a|--allowed] [-l|--literal] [--global] <pattern> git secrets --add-provider [--global] <command> [arguments...] git secrets --register-aws [--global] git secrets --aws-provider [<credentials-file>]
git-secrets scans commits, commit messages, and --no-ff merges to
prevent adding secrets into your git repositories. If a commit,
commit message, or any commit in a --no-ff merge history matches one of
your configured prohibited regular expression patterns, then the commit is
rejected.
git-secrets must be placed somewhere in your PATH so that it is picked up
by git when running git secrets.
You can use the install target of the provided Makefile to install git secrets and the man page.
You can customize the install path using the PREFIX and MANPREFIX variables.
make install
Run the provided install.ps1 powershell script. This will copy the needed files
to an installation directory (%USERPROFILE%/.git-secrets by default) and add
the directory to the current user PATH.
PS > ./install.ps1
brew install git-secrets
Warning
You're not done yet! You MUST install the git hooks for every repo that
you wish to use with git secrets --install.
Here's a quick example of how to ensure a git repository is scanned for secrets on each commit:
cd /path/to/my/repo git secrets --install git secrets --register-aws
Add a configuration template if you want to add hooks to all repositories you initialize or clone in the future.
git secrets --register-aws --global
Add hooks to all your local repositories.
git secrets --install ~/.git-templates/git-secrets git config --global init.templateDir ~/.git-templates/git-secrets
Add custom providers to scan for security credentials.
git secrets --add-provider -- cat /path/to/secret/file/patterns
With git-secrets is also possible to scan a repository including all revisions:
git secrets --scan-history
Each of these options must appear first on the command line.
--install- Installs git hooks for a repository. Once the hooks are installed for a git repository, commits and non-fast-forward merges for that repository will be prevented from committing secrets.
--scan- Scans one or more files for secrets. When a file contains a secret, the
matched text from the file being scanned will be written to stdout and the
script will exit with a non-zero status. Each matched line will be written with
the name of the file that matched, a colon, the line number that matched,
a colon, and then the line of text that matched. If no files are provided,
all files returned by
git ls-filesare scanned. --scan-history- Scans repository including all revisions. When a file contains a secret, the matched text from the file being scanned will be written to stdout and the script will exit with a non-zero status. Each matched line will be written with the name of the file that matched, a colon, the line number that matched, a colon, and then the line of text that matched.
--list- Lists the
git-secretsconfiguration for the current repo or in the global git config. --add- Adds a prohibited or allowed pattern.
--add-provider- Registers a secret provider. Secret providers are executables that when
invoked output prohibited patterns that
git-secretsshould treat as prohibited. --register-awsAdds common AWS patterns to the git config and ensures that keys present in
~/.aws/credentialsare not found in any commit. The following checks are added:- AWS Access Key IDs via
(A3T[A-Z0-9]|AKIA|AGPA|AIDA|AROA|AIPA|ANPA|ANVA|ASIA)[A-Z0-9]{16} - AWS Secret Access Key assignments via ":" or "=" surrounded by optional quotes
- AWS account ID assignments via ":" or "=" surrounded by optional quotes
- Allowed patterns for example AWS keys (
AKIAIOSFODNN7EXAMPLEandwJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY) - Known credentials from
~/.aws/credentials
Note
While the patterns registered by this command should catch most instances of AWS credentials, these patterns are not guaranteed to catch them all.
git-secretsshould be used as an extra means of insurance -- you still need to do your due diligence to ensure that you do not commit credentials to a repository.- AWS Access Key IDs via
--aws-provider- Secret provider that outputs credentials found in an INI file. You can optionally provide the path to an INI file.
-f, --force- Overwrites existing hooks if present.
<target-directory>When provided, installs git hooks to the given directory. The current directory is assumed if
<target-directory>is not provided.If the provided
<target-directory>is not in a git repository, the directory will be created and hooks will be placed in<target-directory>/hooks. This can be useful for creating git template directories using withgit init --template <target-directory>.You can run
git initon a repository that has already been initialized. From the git init documentation:From the git documentation: Running
git initin an existing repository is safe. It will not overwrite things that are already there. The primary reason for rerunninggit initis to pick up newly added templates (or to move the repository to another place if--separate-git-diris given).The following git hooks are installed:
pre-commit: Used to check if any of the files changed in the commit use prohibited patterns.commit-msg: Used to determine if a commit message contains a prohibited patterns.prepare-commit-msg: Used to determine if a merge commit will introduce a history that contains a prohibited pattern at any point. Please note that this hook is only invoked for non fast-forward merges.
Note
Git only allows a single script to be executed per hook. If the repository contains Debian-style subdirectories like
pre-commit.dandcommit-msg.d, then the git hooks will be installed into these directories, which assumes that you've configured the corresponding hooks to execute all of the scripts found in these directories. If these git subdirectories are not present, then the git hooks will be installed to the git repo's.git/hooksdirectory.
Install git hooks to the current directory:
cd /path/to/my/repository git secrets --install
Install git hooks to a repository other than the current directory:
git secrets --install /path/to/my/repository
Create a git template that has git-secrets installed, and then copy that
template into a git repository:
git secrets --install ~/.git-templates/git-secrets git init --template ~/.git-templates/git-secrets
Overwrite existing hooks if present:
git secrets --install -f
-r, --recursiveScans the given files recursively. If a directory is encountered, the directory will be scanned. If
-ris not provided, directories will be ignored.-rcannot be used alongside--cached,--no-index, or--untracked.--cached- Searches blobs registered in the index file.
--no-index- Searches files in the current directory that is not managed by git.
--untracked- In addition to searching in the tracked files in the working tree,
--scanalso in untracked files. <files>...The path to one or more files on disk to scan for secrets.
If no files are provided, all files returned by
git ls-filesare scanned.
Scan all files in the repo:
git secrets --scan
Scans a single file for secrets:
git secrets --scan /path/to/file
Scans a directory recursively for secrets:
git secrets --scan -r /path/to/directory
Scans multiple files for secrets:
git secrets --scan /path/to/file /path/to/other/file
You can scan by globbing:
git secrets --scan /path/to/directory/*
Scan from stdin:
echo 'hello!' | git secrets --scan -
--global- Lists only git-secrets configuration in the global git config.
--global- Adds patterns to the global git config
-l, --literal- Escapes special regular expression characters in the provided pattern so that the pattern is searched for literally.
-a, --allowed- Mark the pattern as allowed instead of prohibited. Allowed patterns are used to filter out false positives.
<pattern>- The regex pattern to search.
Adds a prohibited pattern to the current repo:
git secrets --add '[A-Z0-9]{20}'
Adds a prohibited pattern to the global git config:
git secrets --add --global '[A-Z0-9]{20}'
Adds a string that is scanned for literally (+ is escaped):
git secrets --add --literal 'foo+bar'
Add an allowed pattern:
git secrets --add -a 'allowed pattern'
--global- Adds AWS specific configuration variables to the global git config.
[<credentials-file>]- If provided, specifies the custom path to an INI file to scan. If not
provided,
~/.aws/credentialsis assumed.
--global- Adds the provider to the global git config.
<command>- Provider command to invoke. When invoked the command is expected to write prohibited patterns separated by new lines to stdout. Any extra arguments provided are passed on to the command.
Registers a secret provider with arguments:
git secrets --add-provider -- git secrets --aws-provider
Cats secrets out of a file:
git secrets --add-provider -- cat /path/to/secret/file/patterns
egrep-compatible regular expressions are used to determine if a commit or
commit message contains any prohibited patterns. These regular expressions are
defined using the git config command. It is important to note that
different systems use different versions of egrep. For example, when running on
macOS, you will use a different version of egrep than when running on something
like Ubuntu (BSD vs GNU).
You can add prohibited regular expression patterns to your git config using
git secrets --add <pattern>.
Sometimes a regular expression might match false positives. For example, git commit SHAs look a lot like AWS access keys. You can specify many different regular expression patterns as false positives using the following command:
git secrets --add --allowed 'my regex pattern'
You can also add regular expressions patterns to filter false positives to a
.gitallowed file located in the repository's root directory. Lines starting
with # are skipped (comment line) and empty lines are also skipped.
First, git-secrets will extract all lines from a file that contain a prohibited match. Included in the matched results will be the full path to the name of the file that was matched, followed by ':', followed by the line number that was matched, followed by the entire line from the file that was matched by a secret pattern. Then, if you've defined allowed regular expressions, git-secrets will check to see if all of the matched lines match at least one of your registered allowed regular expressions. If all of the lines that were flagged as secret are canceled out by an allowed match, then the subject text does not contain any secrets. If any of the matched lines are not matched by an allowed regular expression, then git-secrets will fail the commit/merge/message.
Important
Just as it is a bad practice to add prohibited patterns that are too
greedy, it is also a bad practice to add allowed patterns that are too
forgiving. Be sure to test out your patterns using ad-hoc calls to
git secrets --scan $filename to ensure they are working as intended.
Sometimes you want to check for an exact pattern match against a set of known
secrets. For example, you might want to ensure that no credentials present in
~/.aws/credentials ever show up in a commit. In these cases, it's better to
leave these secrets in one location rather than spread them out across git
repositories in git configs. You can use "secret providers" to fetch these
types of credentials. A secret provider is an executable that when invoked
outputs prohibited patterns separated by new lines.
You can add secret providers using the --add-provider command:
git secrets --add-provider -- git secrets --aws-provider
Notice the use of --. This ensures that any arguments associated with the
provider are passed to the provider each time it is invoked when scanning
for secrets.
Let's take a look at an example. Given the following subject text (stored in
/tmp/example):
This is a test! password=ex@mplepassword password=****** More test...
And the following registered patterns:
git secrets --add 'password\s*=\s*.+' git secrets --add --allowed --literal 'ex@mplepassword'
Running git secrets --scan /tmp/example, the result will
result in the following error output:
/tmp/example:3:password=****** [ERROR] Matched prohibited pattern Possible mitigations: - Mark false positives as allowed using: git config --add secrets.allowed ... - List your configured patterns: git config --get-all secrets.patterns - List your configured allowed patterns: git config --get-all secrets.allowed - Use --no-verify if this is a one-time false positive
Breaking this down, the prohibited pattern value of password\s*=\s*.+ will
match the following lines:
/tmp/example:2:password=ex@mplepassword /tmp/example:3:password=******
...But the first match will be filtered out due to the fact that it matches the
allowed regular expression of ex@mplepassword. Because there is still a
remaining line that did not match, it is considered a secret.
Because that matching lines are placed on lines that start with the filename
and line number (e.g., /tmp/example:3:...), you can create allowed
patterns that take filenames and line numbers into account in the regular
expression. For example, you could whitelist an entire file using something
like:
git secrets --add --allowed '/tmp/example:.*' git secrets --scan /tmp/example && echo $? # Outputs: 0
Alternatively, you could allow a specific line number of a file if that line is unlikely to change using something like the following:
git secrets --add --allowed '/tmp/example:3:.*' git secrets --scan /tmp/example && echo $? # Outputs: 0
Keep this in mind when creating allowed patterns to ensure that your allowed patterns are not inadvertently matched due to the fact that the filename is included in the subject text that allowed patterns are matched against.
Use the --no-verify option in the event of a false positive match in a
commit, merge, or commit message. This will skip the execution of the
git hook and allow you to make the commit or merge.
- Author: Michael Dowling
- Issue tracker: This project's source code and issue tracker can be found at https://github.com/awslabs/git-secrets
- Special thanks to Adrian Vatchinsky and Ari Juels of Cornell University for providing suggestions and feedback.
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