CVE-2019-10155 in Libreswan
Summary
by MITRE
The Libreswan Project has found a vulnerability in the processing of IKEv1 informational exchange packets which are encrypted and integrity protected using the established IKE SA encryption and integrity keys, but as a receiver, the integrity check value was not verified. This issue affects versions before 3.29.
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Analysis
by VulDB Data Team • 10/05/2023
The vulnerability identified as CVE-2019-10155 resides within the Libreswan implementation of the Internet Key Exchange version 1 protocol, specifically during the processing of informational exchange packets. This flaw represents a critical security weakness in the cryptographic integrity verification mechanisms that protect IKEv1 communications. The Libreswan project, which provides open source implementations of IPsec and IKE protocols for secure network communications, was found to have a significant gap in its packet validation logic that could allow attackers to manipulate encrypted informational exchanges without detection.
The technical flaw manifests in the improper handling of integrity checks during IKEv1 informational exchanges that are encrypted using established IKE Security Associations. While these packets are correctly encrypted with the session keys, the system fails to validate the integrity check values that should be verified upon receipt. This represents a direct violation of cryptographic best practices and security protocols, as the system accepts potentially tampered packets without confirming their authenticity. The vulnerability exists specifically in versions prior to 3.29, indicating that this was a well-known issue that required a specific version update to resolve.
The operational impact of this vulnerability is substantial as it allows for undetected manipulation of informational exchange packets within IKEv1 communications. Attackers could potentially modify parameters, flags, or other data within these packets without the receiving system detecting the tampering, potentially leading to unauthorized changes in security policies, altered authentication parameters, or other malicious modifications to the IKE exchange process. This weakness undermines the fundamental security guarantees that IKEv1 is designed to provide, creating opportunities for man-in-the-middle attacks, session hijacking, or other forms of cryptographic manipulation that could compromise the entire IPsec tunnel establishment process.
This vulnerability aligns with CWE-310, which addresses cryptographic issues related to the lack of proper integrity checking mechanisms. The flaw also maps to ATT&CK technique T1552.001, which covers unsecured credentials, as the inability to verify packet integrity could lead to credential manipulation within the IKE exchange. Organizations using vulnerable versions of Libreswan should immediately implement the patch available in version 3.29 or later, which properly implements integrity verification checks for informational exchange packets. Network administrators should also consider implementing additional monitoring for unusual IKE traffic patterns and ensure that all IPsec implementations are regularly updated to maintain security posture against known vulnerabilities in cryptographic protocol implementations.