vulnerability

Amazon Linux 2023: CVE-2024-33655: Important priority package update for unbound

Severity
4
CVSS
(AV:N/AC:M/Au:N/C:N/I:N/A:P)
Published
May 9, 2024
Added
Feb 17, 2025
Modified
Jul 9, 2025

Description

The DNS protocol in RFC 1035 and updates allows remote attackers to cause a denial of service (resource consumption) by arranging for DNS queries to be accumulated for seconds, such that responses are later sent in a pulsing burst (which can be considered traffic amplification in some cases), aka the "DNSBomb" issue.
A DNSBomb flaw was found in the unbound package. The DNSBomb attack works by sending low-rate spoofed queries for a malicious zone to Unbound. By controlling the delay of the malicious authoritative answers, Unbound slowly accumulates pending answers for the spoofed addresses. When the authoritative answers become available to Unbound at the same time, Unbound starts serving all the accumulated queries. This results in large-sized, concentrated response bursts to the spoofed addresses.

Solutions

amazon-linux-2023-upgrade-python3-unboundamazon-linux-2023-upgrade-python3-unbound-debuginfoamazon-linux-2023-upgrade-unboundamazon-linux-2023-upgrade-unbound-anchoramazon-linux-2023-upgrade-unbound-anchor-debuginfoamazon-linux-2023-upgrade-unbound-debuginfoamazon-linux-2023-upgrade-unbound-debugsourceamazon-linux-2023-upgrade-unbound-develamazon-linux-2023-upgrade-unbound-libsamazon-linux-2023-upgrade-unbound-libs-debuginfoamazon-linux-2023-upgrade-unbound-utilsamazon-linux-2023-upgrade-unbound-utils-debuginfo
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