CVE-2024-6640

MEDIUM

Incorrect Default Permissions (CWE-276)

2024-08-12 secteam@freebsd.org

Privilege Escalation

6.3

CVSS 3.1 · Vendor: freebsd

Severity by source

Vendor (freebsd) PRIMARY

6.3 MEDIUM

AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L

Primary rating from Vendor (freebsd) · only source for this CVE.

CVSS VectorVendor: freebsd

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

Low

Availability

Low

Lifecycle Timeline

CVE Published

Aug 12, 2024 - 13:38 cve.org

MEDIUM 6.3

DescriptionCVE.org

In ICMPv6 Neighbor Discovery (ND), the ID is always 0. When pf is configured to allow ND and block incoming Echo Requests, a crafted Echo Request packet after a Neighbor Solicitation (NS) can trigger an Echo Reply. The packet has to come from the same host as the NS and have a zero as identifier to match the state created by the Neighbor Discovery and allow replies to be generated.

ICMPv6 packets with identifier value of zero bypass firewall rules written on the assumption that the incoming packets are going to create a state in the state table.

AnalysisAI

In ICMPv6 Neighbor Discovery (ND), the ID is always 0. Rated medium severity (CVSS 6.3), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.

Technical ContextAI

This vulnerability is classified as Incorrect Default Permissions (CWE-276), which allows attackers to access resources due to overly permissive default settings. In ICMPv6 Neighbor Discovery (ND), the ID is always 0. When pf is configured to allow ND and block incoming Echo Requests, a crafted Echo Request packet after a Neighbor Solicitation (NS) can trigger an Echo Reply. The packet has to come from the same host as the NS and have a zero as identifier to match the state created by the Neighbor Discovery and allow replies to be generated. ICMPv6 packets with identifier value of zero bypass firewall rules written on the assumption that the incoming packets are going to create a state in the state table.

Affected ProductsAI

See vendor advisory for affected versions.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Set restrictive default permissions, follow principle of least privilege, review defaults during deployment.