The OWASP Amass tool suite obtains subdomain names by scraping data sources, recursive brute forcing, crawling web archives, permuting/altering names and reverse DNS sweeping. Additionally, Amass uses the IP addresses obtained during resolution to discover associated netblocks and ASNs. All the information is then used to build maps of the target networks.
A precompiled version is available for each release.
If you are on a distribution such as Kali Linux, and have never used snap previously, follow these steps to access snap packages:
$ sudo apt install snapd
$ sudo systemctl start snapd
Add the snap binaries to your PATH using a method similar to the following:
$ export PATH=$PATH:/snap/bin
If your operating environment supports Snap, you can click here to install, or perform the following from the command-line:
$ sudo snap install amass
If you would like snap to get you the latest unstable build of OWASP Amass, type the following command:
$ sudo snap install --edge amass
Periodically, execute the following command to update all your snap packages:
$ sudo snap refresh
- Build the Docker image:
sudo docker build -t amass https://github.com/OWASP/Amass.git
- Run the Docker image:
sudo docker run amass --passive -d example.com
If you would prefer to build your own binary from the latest version of the source code, make sure you have a correctly configured Go >= 1.10 environment. More information about how to achieve this can be found on the golang website. Then, take the following steps:
- Download amass:
$ go get -u github.com/OWASP/Amass/...
- If you wish to rebuild the binaries from the source code:
$ cd $GOPATH/src/github.com/OWASP/Amass
$ go install ./...
At this point, the binaries should be in $GOPATH/bin.
- Several wordlists can be found in the following directory:
$ ls $GOPATH/src/github.com/OWASP/Amass/wordlists/
The most basic use of the tool, which includes reverse DNS lookups and name alterations:
$ amass -d example.com
The example below is a good place to start with amass:
$ amass -v -ip -brute -min-for-recursive 3 -d example.com
[Google] www.example.com
[VirusTotal] ns.example.com
...
13139 names discovered - archive: 171, cert: 2671, scrape: 6290, brute: 991, dns: 250, alt: 2766
Add some additional domains to the enumeration:
$ amass -d example1.com,example2.com -d example3.com
Switches available through the amass CLI:
Flag | Description | Example |
---|---|---|
-active | Enable active recon methods | amass -active -d example.com net -p 80,443,8080 |
-bl | Blacklist undesired subdomains from the enumeration | amass -bl blah.example.com -d example.com |
-blf | Identify blacklisted subdomains from a file | amass -blf data/blacklist.txt -d example.com |
-brute | Perform brute force subdomain enumeration | amass -brute -d example.com |
-d | Provide a domain name to include in the enumeration | amass -d example.com |
-df | Specify the domains to be enumerated via text file | amass -df domains.txt |
-do | Write all the data operations to a JSON file | amass -do data.json -d example.com |
-h | Show the amass usage information | amass -h |
-ip | Print IP addresses with the discovered names | amass -ip -d example.com |
-json | All discoveries written as individual JSON objects | amass -json out.json -d example.com |
-l | List all the domains to be used during enumeration | amass -whois -l -d example.com |
-log | Log all error messages to a file | amass -log amass.log -d example.com |
-min-for-recursive | Number of subdomain names required for recursive brute forcing to begin | amass -brute -min-for-recursive 3 -d example.com |
-noalts | Disable alterations of discovered names | amass -noalts -d example.com |
-passive | A purely passive mode of execution | amass --passive -d example.com |
-norecursive | Disable recursive brute forcing | amass -brute -norecursive -d example.com |
-o | Write the results to a text file | amass -o out.txt -d example.com |
-oA | Output to all available file formats with prefix | amass -oA amass_scan -d example.com |
-r | Specify your own DNS resolvers | amass -r 8.8.8.8,1.1.1.1 -d example.com |
-rf | Specify DNS resolvers with a file | amass -rf data/resolvers.txt -d example.com |
-v | Output includes data source and summary information | amass -v -d example.com |
-version | Print the version number of amass | amass -version |
-w | Change the wordlist used during brute forcing | amass -brute -w wordlist.txt -d example.com |
-whois | Search using reverse whois information | amass -whois -d example.com |
If you need Amass to run faster, then you have three choices:
- Only use the passive data sources:
$ amass --passive -d example.com
- Turn off the subdomain name alteration / permutation service:
$ amass --noalts -d example.com
- Increase the maximum number of file descriptors for a process:
The following Linux/Unix command will show you the hard limit for file descriptors used by amass.
$ ulimit -Hn
The superuser can change this hard limit to grant a larger number of file descriptors to running processes. Raising this limit will cause amass to perform more DNS resolutions simultaneously, and allow enumerations to complete faster. On Linux systems, this can usually be accomplished within the /etc/security/limits.conf file.
Caution: If you use the amass.netdomains tool, it will attempt to reach out to every IP address within the identified infrastructure and obtain domains names from reverse DNS requests and TLS certificates. This is "loud" and can reveal your reconnaissance activities to the organization being investigated.
Lookup ASNs by searching the descriptions registered by organizations:
$ amass.netdomains -org Facebook
32934, US, ARIN, FACEBOOK - Facebook, Inc., US
54115, US, ARIN, FACEBOOK-CORP - Facebook Inc, US
63293, US, ARIN, FACEBOOK-OFFNET - Facebook, Inc., US
To discover all domains hosted within target ASNs, use the following option:
$ amass.netdomains -asn 13374,14618
To investigate target CIDRs, use this option:
$ amass.netdomains -cidr 192.184.113.0/24,104.154.0.0/15
For specific IPs or address ranges, use this option:
$ amass.netdomains -addr 192.168.1.44,192.168.2.1-64
By default, port 443 will be checked for certificates, but the ports can be changed as follows:
$ amass.netdomains -cidr 192.168.1.0/24 -p 80,443,8080
Create enlightening network graph visualizations that provide structure to the information you gather. This tool requires an input file generated by the amass '-do' flag.
Switches for outputting the DNS and infrastructure findings as a network graph:
Flag | Description | Example |
---|---|---|
-d3 | Output a D3.js v4 force simulation HTML file | amass.viz -d3 net.html -i data_ops.json |
-gexf | Output to Graph Exchange XML Format (GEXF) | amass.viz -gephi net.gexf -i data_ops.json |
-graphistry | Output Graphistry JSON | amass.viz -graphistry net.json -i data_ops.json |
-visjs | Output HTML that employs VisJS | amass.viz -visjs net.html -i data_ops.json |
Have amass send all the DNS and infrastructure information gathered to a graph database. This tool requires an input file generated by the amass '-do' flag.
$ amass.db -neo4j neo4j:DoNotUseThisPassword@localhost:7687 -i data_ops.json
If you are using the amass package within your own Go code, be sure to properly seed the default pseudo-random number generator:
import(
"fmt"
"math/rand"
"time"
"github.com/OWASP/Amass/amass"
)
func main() {
rand.Seed(time.Now().UTC().UnixNano())
enum := amass.NewEnumeration()
go func() {
for result := range enum.Output {
fmt.Println(result.Name)
}
}()
enum.AddDomain("example.com")
enum.Start()
}
- Setup a new local transform within Maltego:
- Configure the local transform to properly execute the go program:
- Go into the Transform Manager, and disable the debug info option:
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Presented at Facebook (and shared publically) for the Sept. 2018 OWASP London Chapter meeting: