CVE-2022-40617

strongSwan before 5.9.8 allows remote attackers to cause a denial of service in the revocation plugin by sending a crafted end-entity (and intermediate CA) certificate that contains a CRL/OCSP URL that points to a server (under the attackers control) that doesnt properly respond but (for example) just does nothing after the initial TCP handshake, or sends an excessive amount of application data.

Weakness

The product does not properly control the allocation and maintenance of a limited resource.

Affected Software

Potential Mitigations

• Mitigation of resource exhaustion attacks requires that the target system either:

• The first of these solutions is an issue in itself though, since it may allow attackers to prevent the use of the system by a particular valid user. If the attacker impersonates the valid user, they may be able to prevent the user from accessing the server in question.

• The second solution is simply difficult to effectively institute – and even when properly done, it does not provide a full solution. It simply makes the attack require more resources on the part of the attacker.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/147.html
• https://cwe.mitre.org/data/definitions/227.html
• https://cwe.mitre.org/data/definitions/492.html

References

• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/J3GAYIOCSLU57C45CO4UE4IV4JZE4W3L/
• https://www.strongswan.org/blog/2022/10/03/strongswan-vulnerability-%28cve-2022-40617%29.html
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/J3GAYIOCSLU57C45CO4UE4IV4JZE4W3L/
• https://www.strongswan.org/blog/2022/10/03/strongswan-vulnerability-%28cve-2022-40617%29.html