CVE-2017-13689 in macOS
Summary
by MITRE
The IKEv1 parser in tcpdump before 4.9.2 has a buffer over-read in print-isakmp.c:ikev1_id_print().
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Analysis
by VulDB Data Team • 12/05/2025
The vulnerability identified as CVE-2017-13689 represents a critical buffer over-read flaw within the Internet Key Exchange version 1 implementation of the tcpdump network analysis tool. This issue specifically affects versions prior to 4.9.2 and resides within the print-isakmp.c source file at the ikev1_id_print() function. The flaw manifests when tcpdump processes network packets containing IKEv1 protocol data, particularly during the parsing of identity payloads within the ISAKMP framework. The vulnerability stems from inadequate bounds checking during the processing of variable-length identity attributes that are part of the IKEv1 protocol negotiation process.
The technical implementation of this vulnerability allows an attacker to craft malicious IKEv1 packets that, when processed by an affected tcpdump instance, trigger a buffer over-read condition. This occurs because the ikev1_id_print() function fails to properly validate the length of incoming identity data before attempting to read beyond the allocated buffer boundaries. The issue is classified as a CWE-125 vulnerability, representing an out-of-bounds read where the application accesses memory locations beyond the intended buffer limits. This type of flaw can lead to information disclosure, application instability, or potentially remote code execution depending on the specific memory layout and exploitation circumstances.
The operational impact of CVE-2017-13689 extends beyond simple network monitoring capabilities, as it affects the fundamental security posture of systems relying on tcpdump for network traffic analysis. When exploited, this vulnerability can cause tcpdump to crash or behave unpredictably, potentially leading to denial of service conditions for network monitoring infrastructure. The attack vector requires only that an attacker be able to inject malicious IKEv1 packets into the network traffic that tcpdump is capturing, which is particularly concerning in environments where network monitoring tools are deployed in critical security infrastructure. This vulnerability aligns with ATT&CK technique T1046, where adversaries may leverage network analysis tools to gain insights into network traffic patterns or exploit weaknesses in monitoring systems to achieve broader objectives.
Organizations utilizing tcpdump for network security monitoring and incident response activities should prioritize immediate remediation of this vulnerability. The most effective mitigation involves upgrading to tcpdump version 4.9.2 or later, which includes proper bounds checking in the ikev1_id_print() function. Additionally, network administrators should consider implementing network segmentation and access controls to limit exposure to potentially malicious IKEv1 traffic, particularly in environments where untrusted network traffic may be present. The vulnerability demonstrates the importance of proper input validation in network protocol parsers and highlights the need for continuous security assessment of network monitoring tools that process potentially malicious traffic. Security teams should also consider implementing intrusion detection systems that can identify and alert on suspicious IKEv1 traffic patterns that may indicate exploitation attempts.