CVE-2018-5388 in strongSwan
Summary
by MITRE
In stroke_socket.c in strongSwan before 5.6.3, a missing packet length check could allow a buffer underflow, which may lead to resource exhaustion and denial of service while reading from the socket.
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Analysis
by VulDB Data Team • 01/27/2025
The vulnerability identified as CVE-2018-5388 affects strongSwan versions prior to 5.6.3 and resides within the stroke_socket.c component of the software. This issue represents a critical flaw in the handling of network packet data that can be exploited to compromise system availability. The vulnerability specifically manifests in the absence of proper validation for packet length parameters during socket operations, creating a condition where malformed or truncated packets can trigger unexpected behavior in the application's memory management routines.
The technical root cause of this vulnerability stems from a buffer underflow condition that occurs when the software attempts to process incoming network data without adequate verification of packet boundaries. This type of flaw falls under the CWE-121 category of buffer underflows, which is classified as a fundamental memory safety issue in software development practices. The missing packet length check creates an environment where the application's socket reading functions can access memory locations beyond the intended buffer boundaries, potentially leading to unpredictable system behavior and resource corruption.
From an operational perspective, this vulnerability presents a significant risk to systems relying on strongSwan for IPsec connectivity and VPN services. Attackers can exploit this weakness by sending specially crafted packets to the affected system, triggering the buffer underflow condition that results in resource exhaustion and subsequent denial of service. The impact extends beyond simple service disruption as the vulnerability can cause the application to crash or become unresponsive, effectively rendering the VPN services unavailable to legitimate users. This makes the vulnerability particularly dangerous in environments where continuous network connectivity is essential for business operations or security infrastructure.
The exploitation of CVE-2018-5388 aligns with several tactics described in the MITRE ATT&CK framework, particularly those related to denial of service attacks and system compromise through memory corruption vulnerabilities. The vulnerability can be classified as a privilege escalation vector in certain scenarios where the affected service runs with elevated privileges, though the primary impact remains focused on availability rather than confidentiality or integrity. Network administrators should consider this vulnerability as part of their broader threat landscape analysis, particularly in environments where IPsec services are exposed to untrusted network segments.
Mitigation strategies for this vulnerability primarily focus on applying the official patches released by strongSwan developers for versions 5.6.3 and later. Organizations should prioritize immediate deployment of these updates across all affected systems to eliminate the buffer underflow condition. Additionally, network segmentation and access control measures can provide temporary protection by limiting exposure of vulnerable systems to potentially malicious traffic. Monitoring systems should be configured to detect unusual patterns in socket operations and packet processing that might indicate exploitation attempts. Regular security assessments and vulnerability scanning should include verification of strongSwan versions to prevent recurrence of this and similar memory safety issues in the software infrastructure.