PowerDNS Security Advisory 2020-07: Cache pollution
- CVE: CVE-2020-25829
- Date: 13th of October 2020
- Affects: PowerDNS Recursor up to and including 4.3.4, 4.2.4 and 4.1.17
- Not affected: 4.3.5, 4.2.5, 4.1.18
- Severity: High
- Impact: Denial of service
- Exploit: This problem can be triggered by sending DNS queries
- Risk of system compromise: No
- Solution: Upgrade to a non-affected version
- Workaround: Filter ANY queries to prevent them from reaching the
recursor.
An issue has been found in PowerDNS Recursor where a remote attacker
can cause the cached records for a given name to be updated to the
‘Bogus’ DNSSEC validation state, instead of their actual DNSSEC
‘Secure’ state, via a DNS ANY query. This results in a denial of
service for installations that always validate (dnssec=validate)
and for clients requesting validation when on-demand validation is
enabled (dnssec=process).