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.
References
Configurations
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History
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Information
Published : 2021-01-20 16:15
Updated : 2024-11-21 05:18
NVD link : CVE-2020-25685
Mitre link : CVE-2020-25685
CVE.ORG link : CVE-2020-25685
JSON object : View
Products Affected
fedoraproject
- fedora
debian
- debian_linux
thekelleys
- dnsmasq
arista
- eos
CWE
CWE-326
Inadequate Encryption Strength