The highest threat from this vulnerability is to data integrity.Ī flaw was found in dnsmasq before version 2.83. If chained with CVE-2020-25684 the attack complexity of a successful attack is reduced. This flaw could be abused to perform a DNS Cache Poisoning attack. This is in contrast with RFC5452, which specifies that the query name is one of the attributes of a query that must be used to match a reply. Due to the weak hash (CRC32 when dnsmasq is compiled without DNSSEC, SHA-1 when it is) this flaw allows an off-path attacker to find several different domains all having the same hash, substantially reducing the number of attempts they would have to perform to forge a reply and get it accepted by dnsmasq. When getting a reply from a forwarded query, dnsmasq checks in forward.c:reply_query(), which is the forwarded query that matches the reply, by only using a weak hash of the query name. If chained with CVE-2020-25684, the attack complexity of a successful attack is reduced. This issue is mentioned in the "Birthday Attacks" section of RFC5452. This flaw allows an off-path attacker on the network to substantially reduce the number of attempts that it would have to perform to forge a reply and have it accepted by dnsmasq. By default, a maximum of 150 pending queries can be sent to upstream servers, so there can be at most 150 queries for the same name. When receiving a query, dnsmasq does not check for an existing pending request for the same name and forwards a new request. The highest threat from this vulnerability is to system availability.Ī flaw was found in dnsmasq before version 2.83. FIX CVE 2017 14491 FOR MAC CODEThis flaw is caused by the lack of length checks in rfc1035.c:extract_name(), which could be abused to make the code execute memcpy() with a negative size in sort_rrset() and cause a crash in dnsmasq, resulting in a denial of service. This flaw allows a remote attacker, who can create valid DNS replies, to cause an overflow in a heap-allocated memory. A heap-based buffer overflow was discovered in dnsmasq when DNSSEC is enabled and before it validates the received DNS entries. This flaw makes a DNS Cache Poisoning attack much easier. An attacker on the network, able to find the outgoing port used by dnsmasq, only needs to guess the random transmission ID to forge a reply and get it accepted by dnsmasq. When configured to use a specific server for a given network interface, dnsmasq uses a fixed port while forwarding queries. Authenticated attackers can reconfigure dnsmasq via a crafted extra_dhcp_opts value.Ī flaw was found in dnsmasq in versions before 2.85. Dnsmasq 2.86 has a heap-based buffer overflow in answer_request (called from FuzzAnswerTheRequest and fuzz_rfc1035.c).ĭnsmasq 2.86 has a heap-based buffer overflow in print_mac (called from log_packet and dhcp_reply).ĭnsmasq 2.86 has a heap-based buffer overflow in resize_packet (called from FuzzResizePacket and fuzz_rfc1035.c).ĭnsmasq 2.86 has a heap-based buffer overflow in extract_name (called from answer_auth and FuzzAuth).ĭnsmasq 2.86 has a heap-based buffer overflow in extract_name (called from hash_questions and fuzz_util.c).ĭnsmasq 2.86 has a heap-based buffer overflow in dhcp_reply (called from dhcp_packet and FuzzDhcp).ĭnsmasq 2.86 has a heap-based buffer overflow in check_bad_address (called from check_for_bogus_wildcard and FuzzCheckForBogusWildcard).Īn issue was discovered in OpenStack Neutron before 16.4.1, 17.x before 17.2.1, and 18.x before 18.1.1.
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