CVE-2018-14467 in tcpdump
Summary
by MITRE
The BGP parser in tcpdump before 4.9.3 has a buffer over-read in print-bgp.c:bgp_capabilities_print() (BGP_CAPCODE_MP).
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Analysis
by VulDB Data Team • 12/03/2025
The vulnerability identified as CVE-2018-14467 represents a critical buffer over-read flaw within the Border Gateway Protocol parser of tcpdump software version 4.9.2 and earlier. This issue specifically affects the bgp_capabilities_print() function located in the print-bgp.c source file, where the parser encounters a malformed BGP capability message with the BGP_CAPCODE_MP identifier. The flaw occurs when tcpdump processes incoming BGP packets that contain improperly formatted multiprotocol extensions, leading to memory access beyond the allocated buffer boundaries. Such buffer over-read conditions typically arise when network packet parsing functions fail to properly validate input data lengths before accessing memory regions, creating potential avenues for exploitation. The vulnerability exists in the context of network traffic analysis tools that process BGP protocol data, which is fundamental to internet routing operations and widely deployed across network infrastructure. This type of memory corruption vulnerability can potentially be exploited by malicious actors to disrupt network monitoring systems or execute arbitrary code on affected systems.
The technical implementation of this vulnerability stems from inadequate input validation within the BGP capability parsing logic. When tcpdump encounters a BGP_CAPCODE_MP capability code, the bgp_capabilities_print() function attempts to read beyond the bounds of a pre-allocated buffer without proper boundary checks. This buffer over-read condition manifests when processing malformed BGP messages that contain unexpected data lengths or malformed capability extensions. The flaw demonstrates characteristics consistent with CWE-125, which describes out-of-bounds read vulnerabilities where programs access memory locations beyond the intended buffer limits. The function fails to validate the length of incoming capability data before attempting to parse and display BGP capabilities, creating a scenario where memory adjacent to the allocated buffer can be accessed and potentially modified. This type of vulnerability falls under the broader category of memory safety issues that have historically been exploited in network protocol parsers due to insufficient bounds checking mechanisms.
The operational impact of CVE-2018-14467 extends beyond simple denial of service conditions to potentially enable more sophisticated attacks on network infrastructure monitoring systems. Network administrators who rely on tcpdump for BGP traffic analysis and troubleshooting may find their monitoring tools compromised when processing maliciously crafted BGP packets. The vulnerability affects systems where tcpdump is deployed for network protocol analysis, particularly in environments where BGP traffic monitoring is critical for network operations and security event detection. When exploited, this buffer over-read could result in application crashes, data corruption, or potentially remote code execution depending on the specific system configuration and memory layout. The attack surface includes any network monitoring system that utilizes tcpdump for BGP packet analysis, making it relevant to network security operations centers, internet service providers, and enterprise network monitoring infrastructures. The vulnerability is particularly concerning because BGP protocol traffic is essential for internet routing and is commonly analyzed by network security tools for detecting anomalies and potential security incidents.
Mitigation strategies for CVE-2018-14467 should prioritize immediate software updates to tcpdump version 4.9.3 or later, which contains the necessary patches to address the buffer over-read condition. Organizations should also implement network segmentation and access controls to limit exposure to potentially malicious BGP traffic, particularly in environments where BGP monitoring is critical. Network administrators should consider deploying intrusion detection systems that can identify and block malformed BGP packets before they reach tcpdump processing components. Additionally, regular vulnerability assessments should include checks for outdated tcpdump installations, and security monitoring should be enhanced to detect unusual tcpdump behavior or application crashes that might indicate exploitation attempts. The fix implemented in tcpdump 4.9.3 addresses the core issue by adding proper bounds checking to the bgp_capabilities_print() function, ensuring that capability data lengths are validated before memory access operations occur. Security teams should also consider implementing network traffic filtering rules that can prevent malformed BGP packets from reaching systems running tcpdump, providing an additional layer of protection against this vulnerability. These measures align with ATT&CK technique T1071.004 for application layer protocol traffic filtering and T1566 for malicious network traffic injection, demonstrating the comprehensive approach needed to defend against such network protocol vulnerabilities.