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https://github.com/aquasecurity/cfsec

Static analysis for CloudFormation templates to identify common misconfiguration
https://github.com/aquasecurity/cfsec

aws aws-cloudformation aws-sam aws-sam-cli cloudformation cloudsecurity go golang hacktoberfest static-analysis

Last synced: about 1 month ago
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Static analysis for CloudFormation templates to identify common misconfiguration

Host: GitHub
URL: https://github.com/aquasecurity/cfsec
Owner: aquasecurity
License: mit
Archived: true
Created: 2021-08-12T13:33:06.000Z (over 3 years ago)
Default Branch: master
Last Pushed: 2022-02-16T13:55:40.000Z (almost 3 years ago)
Last Synced: 2024-08-02T07:22:57.502Z (4 months ago)
Topics: aws, aws-cloudformation, aws-sam, aws-sam-cli, cloudformation, cloudsecurity, go, golang, hacktoberfest, static-analysis
Language: Go
Homepage: https://aquasecurity.github.io/cfsec
Size: 9.79 MB
Stars: 58
Watchers: 3
Forks: 7
Open Issues: 0
Metadata Files:
- Readme: README.md
- License: LICENSE

Awesome Lists containing this project

DevSecOps - https://github.com/aquasecurity/cfsec - the-badge) | (Infrastructure as code security)

README

> ⚠️ The CloudFormation scanning logic is now integrated with [Aquasecurity Trivy](https://github.com/aquasecurity/trivy). cfsec will no longer be maintained as a stand alone scanner and Trivy should be used

[![GoReportCard](https://goreportcard.com/badge/github.com/aquasecurity/cfsec)](https://goreportcard.com/report/github.com/aquasecurity/cfsec)
[![GitHub All Releases](https://img.shields.io/github/downloads/aquasecurity/cfsec/total)](https://github.com/aquasecurity/cfsec/releases)

## What is it?

cfsec scans your yaml or json CloudFormation configuration files for common security misconfigurations.

## Installation

### Home Brew - Mac and Linux

```shell
brew tap cfsec/cfsec
```

### Chocolatey - Windows

```shell
choco install cfsec
```

### Scoop - Windows

```shell
scoop install cfsec
```

### Installing latest from source

```shell
go install github.com/aquasecurity/cmd/cfsec@latest
```

## An Example

Given the CloudFormation configuration file below;

```yaml
---
AWSTemplateFormatVersion: "2010-09-09"
Description: An example Stack for a bucket
Parameters:
BucketName:
Type: String
Default: naughty-bucket
EncryptBucket:
Type: Boolean
Default: false
Resources:
S3Bucket:
Type: 'AWS::S3::Bucket'
Properties:
BucketName:
Ref: BucketName
PublicAccessBlockConfiguration:
BlockPublicAcls: false
BlockPublicPolicy: false
IgnorePublicAcls: true
RestrictPublicBuckets: false
BucketEncryption:
ServerSideEncryptionConfiguration:
- BucketKeyEnabled: !Ref EncryptBucket
```

Running the command `cfsec example.yaml`

The output would be

```
Result 1

Impact: PUT calls with public ACLs specified can make objects public
Resolution: Enable blocking any PUT calls with a public ACL specified

More Info:
- https://cfsec.dev/docs/s3/block-public-acls/#s3
- https://docs.aws.amazon.com/AmazonS3/latest/userguide/access-control-block-public-access.html

Result 2

Impact: Users could put a policy that allows public access
Resolution: Prevent policies that allow public access being PUT

More Info:
- https://cfsec.dev/docs/s3/block-public-policy/#s3
- https://docs.aws.amazon.com/AmazonS3/latest/dev-retired/access-control-block-public-access.html

Result 3

Impact: The bucket objects could be read if compromised
Resolution: Configure bucket encryption

More Info:
- https://cfsec.dev/docs/s3/enable-bucket-encryption/#s3
- https://docs.aws.amazon.com/AmazonS3/latest/userguide/bucket-encryption.html

Result 4

Impact: There is no way to determine the access to this bucket
Resolution: Add a logging block to the resource to enable access logging

More Info:
- https://cfsec.dev/docs/s3/enable-bucket-logging/#s3
- https://docs.aws.amazon.com/AmazonS3/latest/dev/ServerLogs.html

Result 5

Impact: Deleted or modified data would not be recoverable
Resolution: Enable versioning to protect against accidental/malicious removal or modification

More Info:
- https://cfsec.dev/docs/s3/enable-versioning/#s3
- https://docs.aws.amazon.com/AmazonS3/latest/userguide/Versioning.html

Result 6

Impact: Public buckets can be accessed by anyone
Resolution: Limit the access to public buckets to only the owner or AWS Services (eg; CloudFront)

More Info:
- https://cfsec.dev/docs/s3/no-public-buckets/#s3
- https://docs.aws.amazon.com/AmazonS3/latest/dev-retired/access-control-block-public-access.html

6 potential problems detected.

```

## More Information

cfsec scans single file Stack configurations with support for Parameters, Mappings and Resources.

## Ignoring Findings

Ignores are available in yaml configurations only.

To add an ignore to a resource - on the line of the check add the ignore.

For example, to ignore S3 bucket encryption errors, you might use

```yaml
---
Resources:
UnencrypedBucketWithIgnore:
Type: AWS::S3::Bucket
Properties:
AccessControl: Private
BucketName: unencryptedbits
BucketEncryption:
ServerSideEncryptionConfiguration:
- BucketKeyEnabled: false # cfsec:ignore:aws-s3-enable-bucket-encryption

```

## Supported Intrinsic functions

Not all CloudFormation intrinsic functions are supported, we cover the list below

```
Ref
Fn::Base64
Fn::Equals
Fn::FindInMap
Fn::GetAtt
Fn::Join
Fn::Select
Fn::Split
Fn::Sub
```

In yaml configurations, cfsec supports both standard an short notation i.e; `!Base64` or `Fn::Base64`

## Limitations

- Not all intrinsic functions are supported
- `ImportValue` requires access to the AWS account which is not currently supported
- `GetAtt` is extremely naive. We don't have visibility of attribute values so it is best effort
- No support for nested stacks. cfsec takes the individual files in isolation with no visibility of what exists in the AWS account

## Comments, Suggestions, Issues

cfsec is very early stages, and we are committed to making it the best it can be. Please raise issues or suggestions through GitHub issues or discussion as appropriate.

`cfsec` is an [Aqua Security](https://aquasec.com) open source project.
Learn about our open source work and portfolio [here](https://www.aquasec.com/products/open-source-projects/).
Join the community, and talk to us about any matter in [GitHub Discussion](https://github.com/aquasecurity/cfsec/discussions) or [Slack](https://slack.aquasec.com).