CVE-2017-12990 in macOS
Summary
by MITRE
The ISAKMP parser in tcpdump before 4.9.2 could enter an infinite loop due to bugs in print-isakmp.c, several functions.
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Analysis
by VulDB Data Team • 12/04/2025
The vulnerability identified as CVE-2017-12990 represents a critical flaw in the ISAKMP parser implementation within tcpdump versions prior to 4.9.2. This issue manifests as an infinite loop condition that occurs when processing specifically crafted ISAKMP packets, fundamentally compromising the network traffic analysis capabilities of systems relying on this tool. The vulnerability resides within the print-isakmp.c source file, where multiple functions contain logic errors that prevent proper packet parsing and lead to unbounded execution cycles. The affected tcpdump versions create a scenario where legitimate network monitoring operations can be disrupted or completely halted by maliciously constructed ISAKMP traffic, potentially enabling denial-of-service attacks against network infrastructure.
The technical nature of this vulnerability stems from improper input validation and handling within the ISAKMP protocol parser component. When tcpdump encounters malformed or specially crafted ISAKMP packets, the parser fails to properly terminate its processing loop, causing the application to consume excessive CPU resources and potentially hang indefinitely. This behavior violates fundamental principles of defensive programming and demonstrates a lack of proper boundary checking and state management in the parser implementation. The vulnerability is particularly concerning because ISAKMP is commonly used in IPsec implementations for establishing secure communication channels, making this flaw exploitable in environments where such protocols are actively monitored or analyzed.
From an operational perspective, this vulnerability presents significant risks to network security operations and infrastructure reliability. Network administrators who rely on tcpdump for monitoring IPsec traffic or conducting security assessments may find their monitoring tools become unresponsive when encountering maliciously crafted packets. The infinite loop condition effectively renders the monitoring system ineffective for the duration of the attack, potentially masking other security incidents or creating blind spots in network visibility. This vulnerability can be exploited by attackers to perform denial-of-service attacks against network monitoring infrastructure, potentially disrupting security operations and creating opportunities for more sophisticated attacks to go undetected.
The impact of CVE-2017-12990 aligns with CWE-835, which specifically addresses the issue of infinite loops in software implementations. This weakness falls under the broader category of software reliability failures that can lead to system instability and service disruption. The vulnerability also maps to ATT&CK technique T1499.004, which covers network disruption attacks through resource exhaustion, as the infinite loop effectively consumes system resources and prevents normal operation. Organizations using tcpdump for network analysis should prioritize immediate patching to version 4.9.2 or later, as this update contains the necessary fixes to properly handle ISAKMP packet parsing and prevent the infinite loop conditions that previously occurred. Additionally, network security teams should implement monitoring for unusual cpu usage patterns that might indicate exploitation attempts, and consider deploying network segmentation or packet filtering rules to limit exposure to potentially malicious ISAKMP traffic.