CVE-1999-1024 in tcpdump
Summary
by MITRE
ip_print procedure in Tcpdump 3.4a allows remote attackers to cause a denial of service via a packet with a zero length header, which causes an infinite loop and core dump when tcpdump prints the packet.
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Analysis
by VulDB Data Team • 11/27/2024
The vulnerability identified as CVE-1999-1024 affects tcpdump version 3.4a and represents a classic denial of service flaw stemming from inadequate input validation within the ip_print procedure. This issue arises when tcpdump processes network packets that contain zero length headers, creating a condition where the software enters an infinite loop during packet analysis. The flaw demonstrates a fundamental lack of boundary checking and input sanitization that was prevalent in network analysis tools of that era, particularly highlighting the absence of proper error handling for malformed network traffic. The vulnerability operates at the protocol parsing layer where tcpdump attempts to interpret and display network packets, making it a critical point of failure in network monitoring and security analysis operations.
The technical exploitation of this vulnerability occurs through the manipulation of packet headers to contain zero length values, which triggers an infinite loop in the ip_print function. When tcpdump encounters such malformed packets, the program's packet parsing logic fails to properly handle the edge case of zero-length headers, causing the software to repeatedly process the same packet data without proper termination conditions. This results in continuous CPU utilization and eventually leads to system resource exhaustion, ultimately causing tcpdump to crash and generate core dumps. The infinite loop mechanism typically involves a packet header parsing routine that fails to account for the possibility of zero-length fields, creating a condition where loop counters or pointer advancement mechanisms become stuck in perpetual iteration.
From an operational perspective, this vulnerability presents significant risks to network monitoring infrastructure and security operations centers that rely on tcpdump for packet analysis. The denial of service impact can be severe as it renders network monitoring tools ineffective during attacks, potentially masking malicious activity or preventing security analysts from investigating network incidents. The vulnerability affects tcpdump's ability to maintain continuous packet capture operations, which are essential for network security monitoring, intrusion detection, and forensic analysis. Organizations using tcpdump for network traffic analysis would experience complete service disruption when encountering specially crafted packets designed to trigger this flaw, leading to potential gaps in network visibility and security coverage.
The vulnerability aligns with CWE-129, which addresses improper validation of input boundaries, and demonstrates characteristics consistent with CWE-691, which covers inadequate loop termination conditions. From an ATT&CK framework perspective, this vulnerability maps to the T1498 technique of network denial of service, where adversaries can exploit software flaws to disrupt network monitoring capabilities. The flaw also relates to T1046 network service scanning, as attackers may use this vulnerability to identify and target systems running vulnerable versions of tcpdump. Mitigation strategies should include immediate patching of tcpdump to version 3.5 or later, which contains fixes for this specific vulnerability, along with implementing network segmentation and monitoring to detect anomalous packet patterns that might indicate exploitation attempts. Network administrators should also consider deploying intrusion prevention systems that can detect and block malformed packets before they reach vulnerable tcpdump instances, while maintaining regular software updates to address similar vulnerabilities in network analysis tools.