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OVAL

ALAS2-2021-1587 --- dnsmasq

ID: oval:org.secpod.oval:def:1700544Date: (C)2021-01-28   (M)2023-12-20
Class: PATCHFamily: unix




A flaw was found in dnsmasq. When getting a reply from a forwarded query, dnsmasq checks in the forward.c:reply_query if the reply destination address/port is used by the pending forwarded queries. However, it does not use the address/port to retrieve the exact forwarded query, substantially reducing the number of attempts an attacker on the network would have to perform to forge a reply and get it accepted by dnsmasq. This issue contrasts with RFC5452, which specifies a query"s attributes that all must be used to match a reply. This flaw allows an attacker to perform a DNS Cache Poisoning attack. If chained with CVE-2020-25685 or CVE-2020-25686 , the attack complexity of a successful attack is reduced. The highest threat from this vulnerability is to data integrity. A flaw was found in 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. Due to the weak hash 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. 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. This flaw could be abused to perform a DNS Cache Poisoning attack. If chained with CVE-2020-25684 the attack complexity of a successful attack is reduced. The highest threat from this vulnerability is to data integrity. A flaw was found in dnsmasq. When receiving a query, dnsmasq does not check for an existing pending request for the same name and forwards a new request. 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. 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. This issue is mentioned in the "Birthday Attacks" section of RFC5452. If chained with CVE-2020-25684 , the attack complexity of a successful attack is reduced. The highest threat from this vulnerability is to data integrity

Platform:
Amazon Linux 2
Product:
dnsmasq
Reference:
ALAS2-2021-1587
CVE-2020-25684
CVE-2020-25685
CVE-2020-25686
CVE    3
CVE-2020-25686
CVE-2020-25685
CVE-2020-25684
CPE    2
cpe:/o:amazon:linux:2
cpe:/a:thekelleys:dnsmasq

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