NLnet Labs Unbound, up to and including version 1.16.1, is vulnerable to a novel type of the "ghost domain names" attack. The vulnerability works by targeting an Unbound instance. Unbound is queried for a rogue domain name when the cached delegation information is about to expire. The rogue nameserver delays the response so that the cached delegation information is expired. Upon receiving the delayed answer containing the delegation information, Unbound overwrites the now expired entries. This action can be repeated when the delegation information is about to expire making the rogue delegation information ever-updating. From version 1.16.2 on, Unbound stores the start time for a query and uses that to decide if the cached delegation information can be overwritten. https://www.nlnetlabs.nl/downloads/unbound/CVE-2022-30698_CVE-2022-30699.txt
Upstream Patch: https://github.com/NLnetLabs/unbound/commit/f6753a0f1018133df552347a199e0362fc1dac68
Created unbound tracking bugs for this issue: Affects: fedora-35 [bug 2116735] Affects: fedora-36 [bug 2116736]
This issue has been addressed in the following products: Red Hat Enterprise Linux 8 Via RHSA-2022:7622 https://access.redhat.com/errata/RHSA-2022:7622
This issue has been addressed in the following products: Red Hat Enterprise Linux 9 Via RHSA-2022:8062 https://access.redhat.com/errata/RHSA-2022:8062
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s): https://access.redhat.com/security/cve/cve-2022-30699