Overview
- 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.
- Source
- secalert@redhat.com
- NVD status
- Modified
Risk scores
CVSS 3.1
- Type
- Primary
- Base score
- 3.7
- Impact score
- 1.4
- Exploitability score
- 2.2
- Vector string
- CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
- Severity
- LOW
CVSS 2.0
- Type
- Primary
- Base score
- 4.3
- Impact score
- 2.9
- Exploitability score
- 8.6
- Vector string
- AV:N/AC:M/Au:N/C:N/I:P/A:N
Social media
- Hype score
- Not currently trending
Configurations
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