QID 357294

Date Published: 2024-03-06

QID 357294: Amazon Linux Security Advisory for unbound : ALAS2023-2024-553

Certain dnssec aspects of the dns protocol (in rfc 4035 and related rfcs) allow remote attackers to cause a denial of service (cpu consumption) via one or more dnssec responses when there is a zone with many dnskey and rrsig records, aka the "keytrap" issue.
The protocol specification implies that an algorithm must evaluate all combinations of dnskey and rrsig records. (
( CVE-2023-50387) the closest encloser proof aspect of the dns protocol (in rfc 5155 when rfc 9276 guidance is skipped) allows remote attackers to cause a denial of service (cpu consumption for sha-1 computations) via dnssec responses in a random subdomain attack, aka the "nsec3" issue.
The rfc 5155 specification implies that an algorithm must perform thousands of iterations of a hash function in certain situations. (
( CVE-2023-50868)



Note: The preceding description block is extracted directly from the security advisory. Using automation, we have attempted to clean and format it as much as possible without introducing additional issues.

Successful exploitation of this vulnerability could lead to a securitybreach or could affect integrity, availability, and confidentiality.

  • CVSS V3 rated as High - 7.5 severity.
  • CVSS V2 rated as Medium - 5.4 severity.
    • Solution
    Please refer to Amazon advisory: ALAS2023-2024-553 for affected packages and patching details, or update with your package manager.
    Vendor References

    CVEs related to QID 357294

    CVE-2023-50387 | CVE-2023-50868 |
    Software Advisories
    Advisory ID Software Component Link
    ALAS2023-2024-553 amazon linux 2023 URL Logo alas.aws.amazon.com/AL2023/ALAS-2024-553.html
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