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Script to detect stale AWS security groups
#!/usr/bin/env python
import boto3
import argparse
class StaleSGDetector(object):
"""
Class to hold the logic for detecting AWS security groups that are stale.
"""
def __init__(self, **kwargs):
super(StaleSGDetector, self).__init__()
self.region = kwargs["region"]
self.profile = kwargs["profile"]
self.all_groups = set()
self.security_groups_in_use = set()
self.stale_groups = set()
self.ec2_instances_count = 0
self.network_interfaces_count = 0
self.elbs_count = 0
self.albs_count = 0
self.rds_count = 0
self.redshift_count = 0
def get_session(self):
"""Gets a new boto3 session"""
kwargs = {}
kwargs['profile_name'] = self.profile
kwargs['region_name'] = self.region
session = boto3.Session(**kwargs)
return session
def run(self):
self.session = self.get_session()
self.get_all_security_groups()
self.get_ec2_security_groups()
self.get_network_interfaces_security_groups()
self.get_elb_security_groups()
self.get_alb_security_groups()
self.get_rds_security_groups()
self.get_redshift_security_groups()
self.calculate_stale_security_groups()
def get_all_security_groups(self):
"""Adds all existing security groups used in the region."""
ec2_client = self.session.client('ec2')
security_groups_dict = ec2_client.describe_security_groups()
security_groups = security_groups_dict['SecurityGroups']
for group in security_groups:
# Default SGs don't have to be deleted.
if group['GroupName'] == 'default':
self.security_groups_in_use.add(group['GroupId'])
self.all_groups.add(group['GroupId'])
def get_ec2_security_groups(self):
"""Adds security groups used by EC2 instances."""
ec2_client = self.session.client('ec2')
instances = ec2_client.describe_instances()
reservations = instances['Reservations']
for reservation in reservations:
for instance in reservation['Instances']:
self.ec2_instances_count += 1
for group in instance['SecurityGroups']:
self.security_groups_in_use.add(group['GroupId'])
def get_network_interfaces_security_groups(self):
"""Adds security groups used by Network Interfaces (ENIs)."""
ec2_client = self.session.client('ec2')
enis = ec2_client.describe_network_interfaces()
for eni in enis['NetworkInterfaces']:
self.network_interfaces_count += 1
for group in eni['Groups']:
self.security_groups_in_use.add(group['GroupId'])
def get_elb_security_groups(self):
"""Adds security groups used by classic elastic loadbalancers (ELBs)."""
elb_client = self.session.client('elb')
elbs = elb_client.describe_load_balancers()
for elb in elbs['LoadBalancerDescriptions']:
self.elbs_count += 1
for group in elb['SecurityGroups']:
self.security_groups_in_use.add(group)
def get_alb_security_groups(self):
"""Adds security groups used by application loadbalancers (ALBs)."""
alb_client = self.session.client('elbv2')
albs = alb_client.describe_load_balancers()
for alb in albs['LoadBalancers']:
self.albs_count += 1
for group in alb['SecurityGroups']:
self.security_groups_in_use.add(group)
def get_rds_security_groups(self):
"""Adds security groups used by RDS."""
rds_client = self.session.client('rds')
rdses = rds_client.describe_db_instances()
for rds in rdses['DBInstances']:
self.rds_count += 1
for group in rds['VpcSecurityGroups']:
self.security_groups_in_use.add(group['VpcSecurityGroupId'])
def get_redshift_security_groups(self):
"""Adds security groups used by Redshift."""
redshift_client = self.session.client('redshift')
redshifts = redshift_client.describe_clusters()
for cluster in redshifts['Clusters']:
self.redshift_count += 1
for group in cluster['VpcSecurityGroups']:
self.security_groups_in_use.add(group['VpcSecurityGroupId'])
def calculate_stale_security_groups(self):
self.stale_groups = self.all_groups.difference(self.security_groups_in_use)
# Check if there is a SG in usd SGs but not in all.
# Could that ever be true?
assert(not self.security_groups_in_use.difference(self.all_groups))
def report(detector_object):
print("---------------")
search_log = (
"Searched through {} EC2 instances, "
"{} network interfaces, {} ELBs, {} ALBs, "
"{} RDS instances, {} Redshift clusters"
).format(
detector_object.ec2_instances_count,
detector_object.network_interfaces_count,
detector_object.elbs_count, detector_object.albs_count,
detector_object.rds_count, detector_object.redshift_count
)
print(search_log)
sg_log = "Found {} Security Groups in total, which {} are in-use.".format(
len(detector_object.all_groups), len(detector_object.security_groups_in_use)
)
print(sg_log)
stale_log = "Following {} security groups don't seem to be used:".format(
len(detector_object.stale_groups)
)
print(stale_log)
for sg in detector_object.stale_groups:
print " - ", sg
print("---------------")
if __name__ == "__main__":
parser = argparse.ArgumentParser(description="Show unused security groups")
parser.add_argument(
"-p", "--profile", type=str, default="default",
help="The AWS profile that will be used."
)
parser.add_argument(
"-r", "--region", type=str, default="eu-west-1",
help="The default region is eu-west-1."
)
parser.add_argument(
"-d", "--delete", help="Delete security groups from AWS",
action="store_true"
)
parser.add_argument(
"-n", "--no-report", help="Skip showing report for Security Groups",
action="store_true", default=False
)
args = parser.parse_args()
detector = StaleSGDetector(
**{"region": args.region, "profile": args.profile}
)
detector.run()
if not args.no_report:
report(detector)
@pierreozoux

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@pierreozoux pierreozoux commented Nov 14, 2017

Thanks for your amazing script, I was exactly looking for that, and thanks to Last week in AWS, here I am!

I did one modification to allow boto to read AWS_PROFILE env variable (instead of reading from args).
This is my workflow, I find it better and I think most tools follow this paradigm, so it is a bit counter intuitive to have to specify it.

If you want, take my fork, and update yours: https://gist.github.com/pierreozoux/98dae7f3f2a5a7bbb40a78f3b7976f33 I think more people would benefit! (No PR on gists :/ )

@craighurley

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@craighurley craighurley commented Dec 21, 2017

line 146:

        print "  - ", sg

should read:

        print("  - ", sg)
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