Squealer

Telling tales on you for leaking secrets!

Squealer scans a git repository or filesystem for secrets that are being leaked deep within the commit history.

The built-in configuration has the following checks;

AWS

• access key id
• access secret key

Github

• github token

Slack

• slack token OAUTH
• webhook url

Other

• Asymmetric Private Key

Sometimes we have secrets committed to our projects, generally we can invalidate them and move on. If squealer is telling tales about a secret that you are aware of and has been mitigated, you can use the exception rule found in the output to register it as ignored.

Installation

curl -s "https://raw.githubusercontent.com/owenrumney/squealer/main/scripts/install.sh" | bash

Usage

Squealer is intended to be run either locally or as part of a CI process.

./squealer --help
Telling tales on your secret leaking

Usage:
  squealer [flags]

Flags:
      --concise                Reduced output.
      --config-file string     Path to the config file with the rules.
      --debug                  Include debug output.
      --everything             Scan all commits.... everywhere.
      --from-hash string       The hash to work back to from the starting hash.
  -h, --help                   help for squealer
      --no-git                 Scan as a directory rather than a git history.
      --output-format string   The format that the output should come in (default, json, sarif.
      --redacted               Display the results redacted.
      --to-hash string         The most recent hash to start with.

Config File

rules:
- rule: (A3T[A-Z0-9]|AKIA|AGPA|AIDA|AROA|AIPA|ANPA|ANVA|ASIA)[A-Z0-9]{16}
  description: Check for AWS Access Key Id
- rule: (?i)aws(.{0,20})?(?-i)['\"][0-9a-zA-Z\/+]{40}['\"]
  description: Check for AWS Secret Access Key
- rule: (?i)github[_\-\.]?token[\s:,="\]']+?(?-i)[0-9a-zA-Z]{35,40}
  description: Check for Github Token 
- rule: https://hooks.slack.com/services/T[a-zA-Z0-9_]{8}/B[a-zA-Z0-9_]{8}/[a-zA-Z0-9_]{24}
  description: Check for Slack webhook
- rule: xox[baprs]-([0-9a-zA-Z]{10,48})?
  description: Check for Slack token
- rule: '-----BEGIN ((EC|PGP|DSA|RSA|OPENSSH) )?PRIVATE KEY( BLOCK)?-----'
  description: Check for Private Asymetric Key
ignore_paths:
- vendor
- node_modules
ignore_extensions:
- .zip
- .png
- .jpg
- .pdf
- .xls
- .doc
- .docx
exceptions:
- exception: release/update.go:D2IDetI6aidl58GE6dv5uAaWmXM=
  reason: This is a webhook that we got rid of - can be ignored in this file

Config breakdown

The config file is made up of the rules, ignore_prefixes, ignore_extensions and exceptions.

rules

Rules define the regular expression that is used to detect the secret. Requires a description for posterity.

ignore_paths

Ignore paths are folders that you don't want to look ing - generally vendor and the like.

ignore_extensions

Ignore extensions have the file types that won't be scanned. Binaries are automatically ignored.

exceptions

Exceptions are the entries that you've already handled and don't want to be reported any more.

Example Output

INFO[0000] Using a git scanner to process ../../tfsec/tfsec
INFO[0000] starting at hash 3bd04e7e17f2aad9e5f38826d88325798534a289

Content:      | access_key = "AKIAABCD12ABCDEF1ABC"
Filename:     | internal/app/tfsec/checks/aws044.go
Line No:      | 21
Secret Hash:  | bcE9jU2WV11OYs63eGHPZf1l9v8=
Commit:       | 4e68e1c5b3bc66982e4b7e6c5cc1c1642c87f83d
Committer:    | GitHub ([email protected])
Committed:    | 2020-10-21 21:59:22 +0100 +0100
Exclude rule: | internal/app/tfsec/checks/aws044.go:bcE9jU2WV11OYs63eGHPZf1l9v8=

Content:      | access_key = "AKIAABCD12ABCDEF1ABC"
Filename:     | docs-website/docs/aws/AWS044.md
Line No:      | 26
Secret Hash:  | bcE9jU2WV11OYs63eGHPZf1l9v8=
Commit:       | 8a7715f2cf5a2ac74a1e186792c476fd52ee1474
Committer:    | ¨Owen Rumney ([email protected])
Committed:    | 2021-01-24 19:04:27 +0000 +0000
Exclude rule: | docs-website/docs/aws/AWS044.md:bcE9jU2WV11OYs63eGHPZf1l9v8=

Processing:
  duration:     2.99s
  commits:      503
  commit files: 4095

transgressionMap:
  identified:   6
  ignored:      0
  reported:     2


INFO[0002] Exit code: 1

It's worth noting that these are known because they're examples in the documentation for tfsec - I can add them to the config.yaml as exclusions y using the Exclude rule

Using as a library

Squealer can be used for scanning a specific string using either the default config or by passing your own file in.

Adding the library

go get -u github.com/owenrumney/squealer

Using as a library

Git and Directory Scanning

package main

import (
	"fmt"
	
	"github.com/owenrumney/squealer/pkg/squealer"
	"github.com/owenrumney/squealer/pkg/config"
)

func main() {

	// create a new scanner (optionally load your own config in)
	scanner, err :=  squealer.New(
		squealer.OptionWithConfig(config.DefaultConfig()), // if not supplied , config.DefaultConfig() used
		squealer.OptionRedactedSecrets(true), // defaults to true, secrets in output redacted
		squealer.OptionNoGitScan(false), // Treat Directories with .git in them as Directories, defaults to false
		squealer.OptionWithBasePath("."), // The path to scan, default is '.'
		squealer.OptionWithFromHash(""), // Specify the starting hash for the scan, useful for PRs
		squealer.OptionWithToHash(""), // Specify the hash to stop scanning, useful for PRs scanning
		squealer.OptionWithScanEverything(false), // Scan everything in every branch, defaults to only the current branch
		squealer.OptionWithCommitListFile(""), // a file of commits that you want to explicitly scan in a text file.
	)

	transgressions, err := scanner.Scan()
	if err != nil {
		panic(err)
	}
	
	for _, t := range transgressions {
		fmt.Printf("%s[%d]\n", t.Filename, t.LineNo)
    }
}

String Scanning

package main

import (
	"fmt"

	"github.com/owenrumney/squealer/pkg/squealer"
)

func main() {

  // create a new scanner (optionally load your own config in)
	scanner := squealer.NewStringScanner()
	testString := `password = "superSecretPassword"`

  // scan the string and if a transgression is found, report it.
	if result := scanner.Scan(testString); result.TransgressionFound {
		fmt.Printf("found an issue in [%s]. %s\n", testString, result.Description)
	}
}

Credits

Image by Derangedmisfit