NLnet Labs Unbound up to and including version 1.21.0 contains a vulnerability when handling replies with very large RRsets that it needs to perform name compression for. Malicious upstreams responses with very large RRsets can cause Unbound to spend a considerable time applying name compression to downstream replies. This can lead to degraded performance and eventually denial of service in well orchestrated attacks. The vulnerability can be exploited by a malicious actor querying Unbound for the specially crafted contents of a malicious zone with very large RRsets. Before Unbound replies to the query it will try to apply name compression which was an unbounded operation that could lock the CPU until the whole packet was complete. Unbound version 1.21.1 introduces a hard limit on the number of name compression calculations it is willing to do per packet. Packets that need more compression will result in semi-compressed packets or truncated packets, even on TCP for huge messages, to avoid locking the CPU for long. This change should not affect normal DNS traffic.
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History
Fri, 04 Oct 2024 13:15:00 +0000
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Thu, 03 Oct 2024 18:30:00 +0000
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Nlnetlabs
Nlnetlabs unbound |
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CPEs | cpe:2.3:a:nlnetlabs:unbound:*:*:*:*:*:*:*:* | |
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Nlnetlabs
Nlnetlabs unbound |
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Thu, 03 Oct 2024 16:45:00 +0000
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Description | NLnet Labs Unbound up to and including version 1.21.0 contains a vulnerability when handling replies with very large RRsets that it needs to perform name compression for. Malicious upstreams responses with very large RRsets can cause Unbound to spend a considerable time applying name compression to downstream replies. This can lead to degraded performance and eventually denial of service in well orchestrated attacks. The vulnerability can be exploited by a malicious actor querying Unbound for the specially crafted contents of a malicious zone with very large RRsets. Before Unbound replies to the query it will try to apply name compression which was an unbounded operation that could lock the CPU until the whole packet was complete. Unbound version 1.21.1 introduces a hard limit on the number of name compression calculations it is willing to do per packet. Packets that need more compression will result in semi-compressed packets or truncated packets, even on TCP for huge messages, to avoid locking the CPU for long. This change should not affect normal DNS traffic. | |
Title | Unbounded name compression could lead to Denial of Service | |
Weaknesses | CWE-606 | |
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cvssV3_1
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MITRE
Status: PUBLISHED
Assigner: NLnet Labs
Published: 2024-10-03T16:27:54.540Z
Updated: 2024-11-14T21:02:40.473Z
Reserved: 2024-09-06T11:47:59.783Z
Link: CVE-2024-8508
Vulnrichment
Updated: 2024-11-14T21:02:40.473Z
NVD
Status : Awaiting Analysis
Published: 2024-10-03T17:15:15.323
Modified: 2024-10-04T13:50:43.727
Link: CVE-2024-8508
Redhat