CloudFrunt - A Tool For Identifying Misconfigured CloudFront Domains

CloudFrunt is a tool for identifying misconfigured CloudFront domains.

Background

CloudFront is a Content Delivery Network (CDN) provided by Amazon Web Services (AWS). CloudFront users create "distributions" that serve content from specific sources (an S3 bucket, for example).

Each CloudFront distribution has a unique endpoint for users to point their DNS records to (ex. d111111abcdef8.cloudfront.net). All of the domains using a specific distribution need to be listed in the "Alternate Domain Names (CNAMEs)" field in the options for that distribution.

When a CloudFront endpoint receives a request, it does NOT automatically serve content from the corresponding distribution. Instead, CloudFront uses the HOST header of the request to determine which distribution to use. This means two things:

1. If the HOST header does not match an entry in the "Alternate Domain Names (CNAMEs)" field of the intended distribution, the request will fail.
   
2. Any other distribution that contains the specific domain in the HOST header will receive the request and respond to it normally.
   

This is what allows the domains to be hijacked. There are many cases where a CloudFront user fails to list all the necessary domains that might be received in the HOST header. For example:

• The domain "test.disloops.com" is a CNAME record that points to "disloops.com".
• The "disloops.com" domain is set up to use a CloudFront distribution.
• Because "test.disloops.com" was not added to the "Alternate Domain Names (CNAMEs)" field for the distribution, requests to "test.disloops.com" will fail.
• Another user can create a CloudFront distribution and add "test.disloops.com" to the "Alternate Domain Names (CNAMEs)" field to hijack the domain.

This means that the unique endpoint that CloudFront binds to a single distribution is effectively meaningless. A request to one specific CloudFront subdomain is not limited to the distribution it is associated with.

Installation

$ pip install boto3
$ pip install netaddr
$ pip install dnspython
$ git clone https://github.com/disloops/cloudfrunt.git
$ cd cloudfrunt
$ git clone https://github.com/darkoperator/dnsrecon.git

CloudFrunt expects the dnsrecon script to be cloned into a subdirectory called dnsrecon.

Usage

cloudfrunt.py [-h] [-l TARGET_FILE] [-d DOMAINS] [-o ORIGIN] [-i ORIGIN_ID] [-s] [-N]

-h, --help                      Show this message and exit
-s, --save                      Save the results to results.txt
-N, --no-dns                    Do not use dnsrecon to expand scope
-l, --target-file TARGET_FILE   File containing a list of domains (one per line)
-d, --domains DOMAINS           Comma-separated list of domains to scan
-o, --origin ORIGIN             Add vulnerable domains to new distributions with this origin
-i, --origin-id ORIGIN_ID       The origin ID to use with new distributions

Example

$ python cloudfrunt.py -o cloudfrunt.com.s3-website-us-east-1.amazonaws.com -i S3-cloudfrunt -l list.txt

 CloudFrunt v1.0.3

 [+] Enumerating DNS entries for google.com
 [-] No issues found for google.com

 [+] Enumerating DNS entries for disloops.com
 [+] Found CloudFront domain --> cdn.disloops.com
 [+] Found CloudFront domain --> test.disloops.com
 [-] Potentially misconfigured CloudFront domains:
 [#] --> test.disloops.com
 [+] Created new CloudFront distribution EXBC12DE3F45G
 [+] Added test.disloops.com to CloudFront distribution EXBC12DE3F45G

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goGetBucket - A Penetration Testing Tool To Enumerate And Analyse Amazon S3 Buckets Owned By A Domain

When performing a recon on a domain - understanding assets they own is very important. AWS S3 bucket permissions have been confused time and time again, and have allowed for the exposure of sensitive material.

What this tool does, is enumerate S3 bucket names using common patterns I have identified during my time bug hunting and pentesting. Permutations are supported on a root domain name using a custom wordlist. I highly recommend the one packaged within AltDNS.

The following information about every bucket found to exist will be returned:

• List Permission
• Write Permission
• Region the Bucket exists in
• If the bucket has all access disabled

Installation

go get -u github.com/glen-mac/goGetBucket

Usage
goGetBucket -m ~/tools/altdns/words.txt -d <domain> -o <output> -i <wordlist>

Usage of ./goGetBucket:
  -d string
        Supplied domain name (used with mutation flag)
  -f string
        Path to a testfile (default "/tmp/test.file")
  -i string
        Path to input wordlist to enumerate
  -k string
        Keyword list (used with mutation flag)
  -m string
        Path to mutation wordlist (requires domain flag)
  -o string
        Path to output file to store log
  -t int
        Number of concurrent threads (default 100)

Throughout my use of the tool, I have produced the best results when I feed in a list (-i) of subdomains for a root domain I am interested in. E.G:

www.domain.com
mail.domain.com
dev.domain.com

The test file (-f) is a file that the script will attempt to store in the bucket to test write permissions. So maybe store your contact information and a warning message if this is performed during a bounty?
The keyword list (-k) is concatenated with the root domain name (-d) and the domain without the TLD to permutate using the supplied permuation wordlist (-m).
Be sure not to increase the threads too high (-t) - as the AWS has API rate limiting that will kick in and start giving an undesired return code.

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