CVE-2017-5205 in macOS
Summary
by MITRE
The ISAKMP parser in tcpdump before 4.9.0 has a buffer overflow in print-isakmp.c:ikev2_e_print().
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 05/16/2026
The vulnerability identified as CVE-2017-5205 represents a critical buffer overflow flaw within the ISAKMP parser functionality of tcpdump software versions prior to 4.9.0. This issue specifically manifests in the print-isakmp.c source file at the ikev2_e_print() function, where inadequate input validation and memory management practices create exploitable conditions that can lead to arbitrary code execution or system compromise. The ISAKMP protocol, which stands for Internet Security Association and Key Management Protocol, is fundamental to establishing secure communications in VPN environments and is widely used in enterprise network security implementations. When tcpdump processes network traffic containing malformed ISAKMP packets, particularly those following the IKEv2 protocol version, the vulnerable code fails to properly bounds-check data structures before copying them into fixed-size buffers, creating opportunities for attackers to manipulate memory layout and potentially execute malicious code with the privileges of the tcpdump process.
The technical exploitation of this vulnerability follows a well-established pattern that aligns with CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations. The flaw occurs during packet processing when tcpdump encounters specially crafted ISAKMP messages that contain oversized or malformed payload data within the IKEv2 extended payload fields. The ikev2_e_print() function does not adequately validate the length of incoming data before attempting to copy it into internal buffers, allowing attackers to overflow these buffers and potentially overwrite return addresses, function pointers, or other critical memory segments. This vulnerability particularly affects systems where tcpdump is executed with elevated privileges, such as when running in promiscuous mode or when used for network monitoring in security-sensitive environments. The attack vector requires the attacker to either be on the same network segment to inject malicious packets or to have some form of network injection capability that allows them to craft and transmit specially formatted ISAKMP traffic toward systems running vulnerable versions of tcpdump.
The operational impact of this vulnerability extends beyond simple denial of service conditions to encompass potential complete system compromise and unauthorized access to network monitoring capabilities. When exploited successfully, the buffer overflow can result in arbitrary code execution, allowing attackers to gain control over the tcpdump process and potentially escalate privileges to the full system level depending on how tcpdump is configured and executed. Network security monitoring systems that rely on tcpdump for packet analysis become particularly vulnerable, as attackers could use this flaw to either corrupt the monitoring process or to inject malicious code that could persist across system reboots. Organizations using tcpdump for security auditing, intrusion detection, or network forensics are at significant risk since these tools often run with elevated privileges and may be deployed in environments where network traffic is continuously monitored. The vulnerability affects not only direct tcpdump usage but also applications that depend on tcpdump for packet analysis, including various network security appliances, IDS/IPS systems, and forensic analysis tools that incorporate tcpdump functionality.
Mitigation strategies for CVE-2017-5205 should prioritize immediate software updates to tcpdump version 4.9.0 or later, which contains the necessary patches to address the buffer overflow condition in the ISAKMP parser. System administrators should also implement network segmentation and access controls to limit exposure of systems running tcpdump to untrusted network segments where malicious packet injection is possible. Network administrators should consider deploying intrusion prevention systems that can detect and block malformed ISAKMP traffic patterns that could be indicators of exploitation attempts. Additionally, organizations should conduct comprehensive vulnerability assessments to identify all systems running vulnerable versions of tcpdump and ensure that appropriate monitoring is in place for detection of potential exploitation attempts. The remediation process should include verification that updated tcpdump installations properly handle ISAKMP packet parsing without overflowing memory buffers, and that normal packet processing continues to function correctly. This vulnerability also highlights the importance of maintaining up-to-date network security tools and implementing robust software supply chain security practices to prevent similar issues from occurring in other security-critical applications that may be vulnerable to similar buffer overflow conditions. From an operational security perspective, organizations should consider implementing network traffic filtering rules that can help prevent the injection of malformed ISAKMP packets into monitored networks, particularly in environments where tcpdump is actively used for security monitoring purposes.