CVE-2015-3966 in mGuard
Summary
by MITRE
The IPsec SA establishment process on Innominate mGuard devices with firmware 8.x before 8.1.7 allows remote authenticated users to cause a denial of service (VPN service restart) by leveraging a peer relationship to send a crafted configuration with compression.
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Analysis
by VulDB Data Team • 06/13/2022
The vulnerability identified as CVE-2015-3966 affects Innominate mGuard devices running firmware versions 8.x before 8.1.7, specifically targeting the IPsec Security Association (SA) establishment process. This flaw represents a critical weakness in the device's ability to handle peer relationships and configuration parameters, particularly those involving compression mechanisms. The vulnerability operates within the context of virtual private network infrastructure where secure communication channels are established through IPsec protocols. The affected devices are designed to provide enterprise-grade security services, making this vulnerability particularly concerning for organizations relying on these systems for network protection.
The technical flaw manifests during the IPsec SA establishment phase when the device receives a crafted configuration from a peer relationship that includes compression parameters. This vulnerability stems from inadequate input validation and error handling within the device's IPsec processing engine. When the mGuard device encounters the specially crafted configuration, it fails to properly validate the compression settings, leading to a buffer overflow or memory corruption condition. The device's failure to handle malformed compression parameters results in an abrupt termination of the IPsec service, causing the VPN service to restart. This behavior aligns with CWE-121, which describes conditions where insufficient memory allocation or improper handling of input data leads to system instability and potential service disruption.
The operational impact of this vulnerability extends beyond simple service interruption, as it can be exploited by remote authenticated users who have already gained access to the device's management interface or network. This makes the attack vector particularly dangerous since the attacker does not need to compromise additional authentication mechanisms to execute the denial of service attack. The VPN service restart can result in significant business disruption, as it immediately terminates active connections and forces users to re-establish their secure network access. Organizations may experience reduced productivity, interrupted critical communications, and potential security gaps during the service restart period. The vulnerability also provides attackers with an opportunity to test system resilience and potentially identify additional weaknesses in the device's security posture.
Mitigation strategies for CVE-2015-3966 should prioritize immediate firmware updates to version 8.1.7 or later, which contain patches addressing the compression parameter handling issue. Network administrators should implement monitoring solutions to detect unusual patterns in IPsec configuration changes and service restarts that may indicate exploitation attempts. The principle of least privilege should be enforced by limiting the number of users with authentication credentials capable of modifying IPsec configurations. Additionally, implementing network segmentation and access controls can reduce the attack surface by limiting which systems can establish peer relationships with the mGuard devices. Organizations should also consider deploying intrusion detection systems specifically configured to monitor for IPsec-related anomalies that could indicate exploitation attempts. From an ATT&CK framework perspective, this vulnerability maps to techniques involving service stoppage and denial of service, while the exploitation process aligns with privilege escalation and persistence mechanisms that attackers might use to maintain access to compromised systems.