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Centos Linux: CVE-2020-25685: Important: dnsmasq security update (Multiple Advisories)

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Centos Linux: CVE-2020-25685: Important: dnsmasq security update (Multiple Advisories)

Severity
4
CVSS
(AV:N/AC:M/Au:N/C:N/I:P/A:N)
Published
01/19/2021
Created
01/20/2021
Added
01/20/2021
Modified
03/03/2021

Description

A flaw was found in dnsmasq before version 2.83. 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 (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. 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.

Solution(s)

  • centos-upgrade-dnsmasq
  • centos-upgrade-dnsmasq-debuginfo
  • centos-upgrade-dnsmasq-debugsource
  • centos-upgrade-dnsmasq-utils
  • centos-upgrade-dnsmasq-utils-debuginfo

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