CVE-2020-25685
20.01.2021, 16:15
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.Enginsight
| Vendor | Product | Version |
|---|---|---|
| thekelleys | dnsmasq | 𝑥 < 2.83 |
| debian | debian_linux | 10.0 |
| arista | eos | 4.21 ≤ 𝑥 < 4.21.14m |
| arista | eos | 4.22 ≤ 𝑥 < 4.22.9m |
| arista | eos | 4.23 ≤ 𝑥 < 4.23.7m |
| arista | eos | 4.24 ≤ 𝑥 < 4.24.5m |
| arista | eos | 4.25 ≤ 𝑥 < 4.25.2f |
𝑥
= Vulnerable software versions
Debian Releases
Ubuntu Releases
Ubuntu Product | |||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| dnsmasq |
|
Common Weakness Enumeration
References