About CORScanner
CORScanner is a python tool designed to discover CORS misconfigurations vulnerabilities of websites. It helps website administrators and penetration testers to check whether the domains/urls they are targeting have insecure CORS policies.
The correct configuration of CORS policy is critical to website security, but CORS configurations have many error-prone corner cases. Web developers who are not aware of these corner cases are likely to make mistakes. Thus, we summarize different common types of CORS misconfigurations and integrate them into this tool, to help developers/security-practioners quickly locate and detect such security issues.
Screenshots
Installation
- Download this tool
git clone https://github.com/chenjj/CORScanner.git
- Install dependencies
sudo pip install -r requirements.txt
CORScanner depends on the requests, gevent, tld and argparse python modules.
Recommended Python Version:
- The recommended version for Python 2 is 2.7.x
Usage
| Short Form | Long Form | Description |
|---|---|---|
| -u | --url | URL/domain to check it's CORS policy |
| -i | --input | URL/domain list file to check their CORS policy |
| -t | --threads | Number of threads to use for CORS scan |
| -o | --output | Save the results to text file |
| -v | --verbose | Enable the verbose mode and display results in realtime |
| -h | --help | show the help message and exit |
Examples
- To check CORS misconfigurations of specific domain:
python cors_scan.py -u example.com
- To check CORS misconfigurations of specific URL:
python cors_scan.py -u http://example.com/restapi
- To check CORS misconfigurations of multiple domains/URLs:
python cors_scan.py -i top_100_domains.txt -t 100
- To list all the basic options and switches use -h switch:
python cors_scan.py -h
Misconfiguration types
| Misconfiguration type | Description |
|---|---|
| Reflect_any_origin | Blindly reflect the Origin header value in Access-Control-Allow-Origin headers in responses |
| Prefix_match | wwww.example.com trusts example.com.evil.com |
| Suffix_match | wwww.example.com trusts evilexample.com |
| Not_escape_dot | wwww.example.com trusts wwwaexample.com |
| Substring match | wwww.example.com trusts example.co |
| trust_null | wwww.example.com trusts null, which can be forged by iframe sandbox scripts |
| HTTPS_trust_HTTP | Risky trust dependency, a MITM attacker may steal HTTPS site secrets |
| trust_any_subdomain | Risky trust dependency, a subdomain XSS may steal its secrets |
License
CORScanner is licensed under the MIT license. take a look at the LICENSE for more information.
Credits
This work is inspired by the following excellent researches:
- James Kettle, “Exploiting CORS misconfigurations for Bitcoins and bounties”, AppSecUSA 2016*
- Evan Johnson, “Misconfigured CORS and why web appsec is not getting easier”, AppSecUSA 2016*
- Von Jens Müller, "CORS misconfigurations on a large scale", CORStest*
Version
Current version is 1.0