Firewall bypass via ICMPv6 state collision
Published Aug 11, 2024 · Updated Nov 26, 2024
Firewall bypass in FreeBSD 13.3 before p5, 14.0 before p9, and 14.1 before p3 allows remote attackers to trigger blocked ICMPv6 Echo Replies. pf keys ICMPv6 state matches on the zero identifier shared by Neighbor Discovery and crafted Echo Requests, so an Echo Request reuses the Neighbor Solicitation state. The packet must come from the host that sent the solicitation, and pf must allow Neighbor Discovery while blocking inbound Echo Requests; successful exploitation returns an Echo Reply that the rule intended to block.
Summary
What happened
Firewall bypass in FreeBSD 13.3 before p5, 14.0 before p9, and 14.1 before p3 allows remote attackers to trigger blocked ICMPv6 Echo Replies. pf keys ICMPv6 state matches on the zero identifier shared by Neighbor Discovery and crafted Echo Requests, so an Echo Request reuses the Neighbor Solicitation state. The packet must come from the host that sent the solicitation, and pf must allow Neighbor Discovery while blocking inbound Echo Requests; successful exploitation returns an Echo Reply that the rule intended to block.
The record
- CVE
- CVE-2024-6640
- Published
- Aug 11, 2024
- Updated
- Nov 26, 2024
- Vendor
- The FreeBSD Project
- Product
- FreeBSD
- Classifications
- CWE-276
- Attack vector
- adjacent
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 11, 2024CVE publishedPublication date reported by the CVE source.
- Nov 26, 2024Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=13.3-RELEASE <p5
- Affected versionversion=14.0-RELEASE <p9
- Affected versionversion=14.1-RELEASE <p3
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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