CVE-2013-7294 in libreswan
Summary
by MITRE
The ikev2parent_inI1outR1 function in pluto/ikev2_parent.c in libreswan before 3.7 allows remote attackers to cause a denial of service (restart) via an IKEv2 I1 notification without a KE payload.
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Analysis
by VulDB Data Team • 12/22/2024
The vulnerability identified as CVE-2013-7294 represents a critical denial of service weakness within the libreswan IPsec implementation, specifically affecting versions prior to 3.7. This flaw resides in the ikev2parent_inI1outR1 function located within the pluto/ikev2_parent.c source file, which governs the processing of IKEv2 protocol messages during the parent SA establishment phase. The vulnerability manifests when the system receives an IKEv2 I1 notification message that lacks the required KE (Key Exchange) payload, creating an exploitable condition that can be leveraged by remote attackers to disrupt the IKE daemon's operation.
The technical nature of this vulnerability stems from insufficient input validation within the IKEv2 processing logic. When the ikev2parent_inI1outR1 function processes incoming IKEv2 messages, it fails to properly validate the presence of mandatory KE payloads in I1 notifications. This oversight creates a path where an attacker can craft malicious IKEv2 packets that bypass normal processing routines, leading to an unexpected state within the pluto daemon. The absence of proper error handling for malformed notifications causes the system to restart or crash, effectively rendering the IPsec service unavailable to legitimate users. This behavior aligns with CWE-476, which describes NULL pointer dereference vulnerabilities, and represents a classic case of inadequate input validation leading to service disruption.
The operational impact of this vulnerability extends beyond simple service interruption, as it can be exploited by remote attackers without requiring authentication or privileged access. The denial of service condition affects the entire IKE daemon, which serves as the core component responsible for establishing and maintaining IPsec security associations. When the pluto service restarts due to this vulnerability, it disrupts all active IPsec connections and prevents new connections from being established, potentially compromising network security by leaving systems unprotected during the restart period. Network administrators may experience significant operational challenges as the service instability can affect multiple connected systems and may require manual intervention to restore normal operations.
Mitigation strategies for this vulnerability should focus on immediate patching of affected libreswan installations to version 3.7 or later, which contains the necessary code fixes to properly validate IKEv2 notification messages. Network defenders should implement monitoring solutions to detect unusual restart patterns in IKE daemons, which could indicate exploitation attempts. The vulnerability's characteristics align with ATT&CK technique T1499.004, which covers network disruption attacks, and organizations should consider implementing network segmentation to limit the impact of such attacks. Additionally, regular security assessments of IPsec implementations and maintaining up-to-date security patches are essential practices to prevent exploitation of similar vulnerabilities in the broader IPsec ecosystem. System administrators should also consider implementing intrusion detection systems that can identify malformed IKEv2 packets and alert security teams to potential exploitation attempts.