Google Cloud Platform Audit
gcp-audit takes a set of projects and audits them for common issues as defined by its ruleset. Issues can include, but are certainly not limited to, storage buckets with read/write permissions for anyone and compute engine instances with services exposed to the Internet.
The results are written to a report containing information about issues that were found along with information about which objects these issues were found in so that it’s possible to address the problems.
gcp-audit is currently in alpha status. We are actively improving it and Spotify’s production environment is our current test suite.
Installation
Run pip install git+https://github.com/spotify/gcp-audit.git.
Usage
usage: gcp-audit.py [-h] [-c CHECKS] [-k KEYFILE] [-o OUTPUT] [-p PROJECTS]
A tool for auditing security properties of GCP projects.
optional arguments:
-h, --help show this help message and exit
-c CHECKS, --checks CHECKS
comma separated list of types of checks to run
-k KEYFILE, --keyfile KEYFILE
keyfile to use for GCP credentials
-o OUTPUT, --output OUTPUT
file to output results to
-p PROJECTS, --projects PROJECTS
comma separated list of GCP projects to audit
Prerequisites
Make sure you have virtualenv (on OSX: brew install virtualenv) then run
virtualenv env
env/bin/pip install gcp-audit
GOOGLE_APPLICATION_CREDENTIALS=YourCredentials-abc123.json env/bin/python gcp-audit
Alternatively you can specify your credentials using the -k switch. Make sure your credentials have the Organization viewer role.
Supported Python versions: 2.7+
Rules
Rules are put in a subdirectory under rules/. The subdirectories are based on the check category. Currently checks for the following categories exist:
bucket_objects – objects within buckets (as opposed to the buckets themselves)
buckets – buckets. 🙂
firewalls – GCP firewall settings
cloudsql – CloudSQL instances
The rule language is fairly simplistic and can be done using YAML (which will be translated to JSON internally) or raw JSON. Each rule can specify the following:
name – the name of the rule that will be shown in reports etc.
filters – a list of filters that the engine should use to match the rule to the object that is being evaluated. This section needs a set of subproperties defined, see below.
matchtype – specifies how the engine should match filter properties. Valid values are “regex”, “exact”, “partial” and “count”. See the “Match types” section below for more details.
filter – a template of properties and values that will be matched against the object. The structure of the filter needs to mimic the structure of the object.
listcondition (OPTIONAL) – what boolean operator to apply if a rule specifies lists with values. Can be “and” or “or”. “and” means all list entries must match. “or” means at least one list entry must match.
filtercondition (OPTIONAL) – what boolean operator to apply between multiple filters. Can be “and” or “or”. “and” means all filters must match. “or” means at least one list entry must match. Default is “and”.
Rules will match against output received from the API’s Google exposes for each service supported by gcp-audit. The official documentation on the API’s can be found here but to make writing rules easier, sample objects for each category are provided in the docs/samples directory. As an example of what a rule can look like, this rule will find CloudSQL instances that are exposed to 0.0.0.0/0:
{
"name": "Traffic allowed from all IP's to CloudSQL instance",
"filters": [{
"matchtype": "exact",
"filter": {
"settings":{
"ipConfiguration":{
"authorizedNetworks":[{
"value":"0.0.0.0/0"
}]
}
}
}
}]
}
And here’s the same rule in YAML format:
name: Traffic allowed from all IP's to CloudSQL instance
filters:
- matchtype: exact
filter:
settings:
ipConfiguration:
authorizedNetworks:
- value: 0.0.0.0/0
The engine will apply the filters defined in the template to the object and check whether the properties match exactly and the values match according to the defined matchtype for each filter.
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