Cloud edge

Lookup an IP to find the cloud provider and other details based on the provider’s published JSON data

Cloud edge is a recon tool focused on exploring cloud service providers. Can be used for pentesting, bug bounty, red teaming, or general R&D of cloud providers. Edge automatically loads Cloud Service Provider (CSP) published IP address ranges (AWS, Azure, GCP) JSON files and performs a prefix lookup based on the input IP address. Can be used to integrate in with other recon tooling. In a black box network pentest, edge quickly discovers which cloud CSP the customer is hosted with, or just double-verifying the scope for rules of engagment. Each of the big three CSPs (Amazon, Azure, GCP) publish a list of all of their IP prefixes and/or netblocks. In some cases this also includes the region/data center and service name. This can be useful for recon and this tool can quickly parse and do a lookup based on IP prefix.

Demo

Cloud edge demo

Input and Output

Here are a few notes on how the tool works for inputs and output.

JSON files from cloud providers

When the tool runs, it looks for the three cloud provider IP address ranges JSON files in the working directory. These files are included in this repo.

If found in working directory, all IP prefixes are loaded into memory. To update the files, you can use the included tool in this repo compiled from http.go to download Google and AWS JSON. Or you can download the latest versions manually. For the Azure JSON file, it needs to be manually downloaded and renamed in the current working directory to azure.json.

The cloud provider IP ranges json files always attempt to load from the working directory. Enabling the actual lookup is done with the -prefix flag.

When -dns mode is enabled, DNS lookups for both A and CNAME records are buffered without display until all DNS queries are finished. After the queries are finished, the output is displayed.

Default CSV Output

With -dns or crt mode, the output is is sent by default to the console as comma delimited results. This makes it easy to use other tools to parse these results.

FQDN,IP,SOURCE,CNAME,DESCRIPTION
  • FQDN: This is the DNS lookup as a FQDN.
  • IP: This is the IP address returned from an A record if found.
  • SOURCE: This is the source of the lookup. Either A, CNAME, or Certificate.
  • CNAME: This returns the CNAME or ALIAS if the request is a CNAME.
  • DESCRIPTION: This returns any results from the IP address ranges description if -prefix is enabled.

With -prefix mode and either -ip or -nmap, the output is sent by default to the console as comma delimited results:

IP,DESCRIPTION

The IP is the IP address and the DESCRIPTION is the results from the IP address ranges lookup in the cloud provider IP address ranges JSON files, if applicable.

With -ptr mode and either ip or nmap, the output is sent by default to the console as comma delimited results:

IP,PTR

The IP is the IP address and the PTR is the results from the DNS PTR lookup if found.

IP Address files with -IP

The -ip flag signals to iterate through a list of IP addresses and can be used in prefix or ptr mode. When you run the tool with -ip <hosts.txt>, it expects each IP address in a separate line, and will iterate through the list doing lookups. Here is an example of the file contents:

[email protected]:~/demo$ cat ip.txt 
3.133.110.237
18.117.232.92
18.221.247.211
3.137.199.52

Nmap XML files

The -nmap flag signals to parse an nmap XML file. It will look for any host in the nmap scan file marked as “Up.” For example, -nmap scan1.xml will tell the tool to parse the scan1.xml file and look for any hosts marked as Up by nmap. You then run it with either -ptr or -prefix to do a lookup of the IP.

Subdomain enumeration with -wordlist

The tool performs classic subdomain enumeration by iterating through a wordlist containing hostnames, one hostname per line. This is used in -dns mode with -wordlist <hosts.txt>. An example of what this looks like for the hosts.txt file:

[email protected]:~/demo$ more subdomains-5k.txt 
www
blog
news
blogs
en
online

Options

$ edge -help
Usage of edge:
  -crt
    	Certificate transparency lookup mode
  -csv string
    	Output results to CSV file
  -dns
    	A and CNAME record lookup mode
  -domain string
    	The domain to perform guessing against.
  -ip string
    	The text file to use with IP addresses
  -nmap string
    	Nmap scan xml file to use.
  -output
    	Enable output to CSV
  -prefix
    	IP Prefix CSP lookup mode
  -ptr
    	PTR lookup mode
  -resolver string
    	The DNS server to use. (default "8.8.8.8:53")
  -verbose
    	Enable verbose output
  -wordlist string
    	The wordlist to use for guessing.
  -workers int
    	The amount of workers to use. (default 10)

Examples

  • $ edge -domain <domain> -dns -crt -prefix -wordlist <wordlist.txt>

Description: Perform a wordlist subdomain enumeration of all A and CNAME records based on wordlist.txt against domain with certificate transparency lookup. For each enumerated host found with Cert transparency, also do a DNS lookup. Do an IP prefix lookup of the IP address across all three cloud service provider’s published list of IP prefixes.

  • $ edge -domain <domain> -dns -wordlist <wordlist.txt>

Description: Perform just a wordlist scan of all A and CNAME records based on wordlist.

  • $ edge -domain <domain> -dns -wordlist <wordlist.txt> -prefix

Description: Perform just a wordlist scan of all A and CNAME records based on wordlist. For every IP address enumerated, perform a prefix lookup.

  • $ edge -domain <domain> -crt

Description: Do a Certificate Transparency log lookup using https://crt.sh

  • $ edge -domain <domain> -dns -crt

Description: Perform a Certificate transparency lookup. For each host discovered via Cert Transparency, do a full DNS A or CNAME lookup.

  • $ edge -prefix -ip <ip-hosts.txt>

Description: Perform a lookup of the IP address for the cloud service provider IP prefix. Takes a list of IP addresses in ip-hosts.txt and looks through it doing a lookup. One IP address per line.

  • $ edge -ptr -ip <ip-hosts.txt>

Description: Does a DNS PTR lookup based on the IP address on each line of ip-hosts.txt.

  • $ edge -prefix -nmap <results.xml>

Description: Parses an nmap scan XML file, identifying all “Up” hosts. For every “Up” host in nmap XML scan results, do an IP prefix lookup for the cloud service provider.

  • $ edge -ptr -nmap <results.txt>

Description: Parses an nmap scan XML file, and does a PTR lookup of every “Up” host.

  • $ edge -domain <domain> -dns -wordlist <wordlist.txt> -workers 100

Description: Uses a DNS concurrency scan of 100 workers. This increases the scan speed. Default workers: 10.

  • $ edge -domain <domain> -dns -wordlist <wordlist.txt> -resolver 8.8.4.4:53

Description: Specify a DNS resolver of 8.8.4.4 on port 53. Default is 8.8.8.8.

  • $ edge -crt -domain <domain> -output -csv <output.csv>

Description: Output results to a CSV file, output.csv.

  • $ edge -crt -domain <domain> -verbose

Description: Enable verbose output.

Installing

Binaries

You can grab the pre-compiled binaries or build it. Make sure you also get the cloud provider IP prefix JSON files.

Building

Tested with go1.18

$ git clone https://github.com/iknowjason/edge.git
$ cd edge
~/edge$ go get -u github.com/miekg/dns
~/edge$ go get -u golang.org/x/net/html
~/edge$ go env -w GO111MODULE=off
~/edge$ go build edge.go
~/edge$ ./edge (Verify it)

Credits

@mosesrenegade for tool inspiration

@0xdabbad00 for general AWS tools and inspiration

This tool was inspired from many other tools and authors, including dnsrecon and gobuster. Yeah I know. Not a lot new here – just another subdomain enumeration tool. I just really wanted to learn Golang 🙂

“Black Hat Go” book

GitHub

View Github