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.
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No Fix Known
No patch has been released yet. Apply workarounds or mitigations where available.
| Vendor | Product | Versions | Fixed In |
|---|---|---|---|
| thekelleys | dnsmasq | 2.83 | - |
| fedoraproject | fedora | - |
Published
CVE disclosed publicly
Last Modified
Most recent update
Indexed to CVEInsight
Added to this platform
AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
9
Affected Products
15
References
thekelleys / dnsmasq
| - |
| fedoraproject | fedora | - | - |
| debian | debian_linux | - | - |
| arista | eos | 4.21 - 4.21.14m | - |
| arista | eos | 4.22 - 4.22.9m | - |
| arista | eos | 4.23 - 4.23.7m | - |
| arista | eos | 4.24 - 4.24.5m | - |
| arista | eos | 4.25 - 4.25.2f | - |
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
Exploitability
Impact