CVE-2024-2357
Description
A flaw was found in Libreswan. This issue causes Libreswan to restart under some IKEv2 retransmit scenarios when a connection is configured to use PreSharedKeys (authby=secret), and the connection cannot find a matching configured secret. When automatically added on startup using the auto= keyword, it can cause repeated crashes, leading to a denial of service.
Statement
Libreswan may restart repeatedly under certain IKEv2 retransmission scenarios when using PreSharedKeys (authby=secret) if the connection cannot find a matching configured secret. If such a connection is added automatically on startup using the auto= keyword, it can lead to repeated crashes, causing a denial of service. The vulnerability arises when IKEv2 fails to find its PreSharedKey for the AUTH payload in the IKE_AUTH Exchange, resulting in assertion failure and daemon crashes. This vulnerability is triggered by local misconfiguration, and there is no known exploitation by external peers.
Mitigation
As a workaround to prevent the misconfiguration from causing the crash, place an unguessable long random "catch-all" secret in /etc/ipsec.secrets, for example, using the following command:
echo -e "# CVE-2024-2357 workaround\n: PSK \"$(openssl rand -hex 32)\"" >> /etc/ipsec.secrets
This will ensure a PSK secret is always found, but it will always be wrong, and thus authentication will still properly fail.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5 | N/A | 6.5 |
| Attack Vector | Local | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | Low | N/A | Low |
| User Interaction | Required | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | None |
| Integrity Impact | None | N/A | None |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory); DoS: Resource Consumption (Other)
If an attacker can trigger the allocation of the limited resources, but the number or size of the resources is not controlled, then the most common result is denial of service. This would prevent valid users from accessing the product, and it could potentially have an impact on the surrounding environment, i.e., the product may slow down, crash due to unhandled errors, or lock out legitimate users. For example, a memory exhaustion attack against an application could slow down the application as well as its host operating system.
Access Control,Other
Technical Impact: Bypass Protection Mechanism; Other
In some cases it may be possible to force the product to "fail open" in the event of resource exhaustion. The state of the product -- and possibly the security functionality - may then be compromised.
Acknowledgements
Red Hat would like to thank Andrew Vaughn for reporting this issue.
Frequently Asked Questions
Not sure what something means? Check out our Security Glossary.
Want to get errata notifications? Sign up here.
