Offensive Security Tool: Whispers
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Offensive Security Tool: Whispers
Whispers
Hardcoded secrets have always been a problem in organizations and are one of the first things Bug Bounty Hunters / Pentesters look for during a penetration test. When developers write secrets such as passwords and API keys directly into source code, these secrets can make their way to public repos or application packages, then into an attacker’s hands. As microservice architectures and API-centric applications become mainstream, developers often need to exchange credentials and other secrets programmatically. This means that developers can sometimes make mistakes when handling sensitive data.
Whispers by Skyscanner, is a static code analysis tool designed for parsing various common data formats in search of hardcoded credentials and dangerous functions. Whispers can run in the CLI or you can integrate it in your CI/CD pipeline.
Detects
- Passwords
- API tokens
- AWS keys
- Private keys
- Hashed credentials
- Authentication tokens
- Dangerous functions
- Sensitive files
See Also: Microsoft is disabling Excel 4.0 macros by default to protect users
Supported Formats
Whispers is intended to be a structured text parser, not a code parser.
The following commonly used formats are currently supported:
- YAML
- JSON
- XML
- npmrc
- pypirc
- htpasswd
- properties
- pip.conf
- conf / ini
- Dockerfile
- Dockercfg
- Shell scripts
- Python3
Python3 files are parsed as ASTs because of native language support.
See Also: Offensive Security & Ethical Hacking Course
Declaration & Assignment Formats
The following language files are parsed as text, and checked for common variable declaration and assignment patterns:
- JavaScript
- Java
- Go
- PHP
Special Formats
- AWS credentials files
- JDBC connection strings
- Jenkins config files
- SpringFramework Beans config files
- Java Properties files
- Dockercfg private registry auth files
- Github tokens
Installation
From PyPI
pip3 install whispers
From GitHub
git clone https://github.com/Skyscanner/whispers
cd whispers
make install
Usage
CLI
whispers –help
whispers –info
whispers source/code/fileOrDir
whispers –config config.yml source/code/fileOrDir
whispers –output /tmp/secrets.yml source/code/fileOrDir
whispers –rules aws-id,aws-secret source/code/fileOrDir
whispers –severity BLOCKER,CRITICAL source/code/fileOrDir
whispers –exitcode 7 source/code/fileOrDir
Python
from whispers.cli import parse_args
from whispers.core import run
src = “tests/fixtures”
configfile = “whispers/config.yml”
args = parse_args([“-c”, configfile, src])
for secret in run(args):
print(secret)
Config
There are several configuration options available in Whispers. It’s possible to include/exclude results based on file path, key, or value. File path specifications are interpreted as globs. Keys and values accept regular expressions and several other parameters. There is a default configuration file built-in that will be used if you don’t provide a custom one.
config.yml should have the following structure:
include:
files:
– “**/*.yml”
exclude:
files:
– “**/test/**/*”
– “**/tests/**/*”
keys:
– ^foo
values:
– bar$
rules:
starks:
message: Whispers from the North
severity: CRITICAL
value:
regex: (Aria|Ned) Stark
ignorecase: True
The fastest way to tweak detection (ie: remove false positives and unwanted results) is to copy the default config.yml into a new file, adapt it, and pass it as an argument to Whispers.
whispers –config config.yml –rules starks src/file/or/dir
Custom Rules
Rules specify the actual things that should be pulled out from key-value pairs. There are several common ones that come built-in, such as AWS keys and passwords, but the tool is made to be easily expandable with new rules.
- Custom rules can be defined in the main config file under rules:
- Custom rules can be added to whispers/rules
rule-id: # unique rule name
description: Values formatted like AWS Session Token
message: AWS Session Token # report will show this message
severity: BLOCKER # one of BLOCKER, CRITICAL, MAJOR, MINOR, INFO
key: # specify key format
regex: (aws.?session.?token)?
ignorecase: True # case-insensitive matching
value: # specify value format
regex: ^(?=.*[a-z])(?=.*[A-Z])[A-Za-z0-9\+\/]{270,450}$
ignorecase: False # case-sensitive matching
minlen: 270 # value is at least this long
isBase64: True # value is base64-encoded
isAscii: False # value is binary data when decoded
isUri: False # value is not formatted like a URI
similar: 0.35 # maximum allowed similarity between key and value
# (1.0 being exactly the same)
Plugins
All parsing functionality is implemented via plugins. Each plugin implements a class with the pairs() method that runs through files and returns the key-value pairs to be checked with rules.
class PluginName:
def pairs(self, file):
yield “key”, “value”
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