QID 357091

Date Published: 2024-02-20

QID 357091: Amazon Linux Security Advisory for unbound : ALAS2-2024-2452

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 subdomain of a rogue domain name.
The rogue nameserver returns delegation information for the subdomain that updates unbound's delegation cache.
This action can be repeated before expiry of the delegation information by querying unbound for a second level subdomain which the rogue nameserver provides new delegation information.
Since unbound is a child-centric resolver, the ever-updating child delegation information can keep a rogue domain name resolvable long after revocation.
From version 1.16.2 on, unbound checks the validity of parent delegation records before using cached delegation information. (
( CVE-2022-30698) nlnet labs unbound, up to and including version 1.16.1, is vulnerable to a novel type of the "ghost domain names" attack.
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.
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. (
( CVE-2022-30699)



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 - 7.8 severity.
  • CVSS V2 rated as Medium - 5.4 severity.
  • Solution
    Please refer to Amazon advisory: ALAS2-2024-2452 for affected packages and patching details, or update with your package manager.
    Vendor References

    CVEs related to QID 357091

    Software Advisories
    Advisory ID Software Component Link
    ALAS2-2024-2452 amazon linux 2 URL Logo alas.aws.amazon.com/AL2/ALAS-2024-2452.html