CVE-2018-16230 in tcpdump
Summary
by MITRE
The BGP parser in tcpdump before 4.9.3 has a buffer over-read in print-bgp.c:bgp_attr_print() (MP_REACH_NLRI).
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Analysis
by VulDB Data Team • 12/03/2025
The vulnerability identified as CVE-2018-16230 represents a critical buffer over-read flaw in the Border Gateway Protocol parser of tcpdump software versions prior to 4.9.3. This issue resides within the print-bgp.c source file at the bgp_attr_print() function specifically when processing MP_REACH_NLRI attributes. The buffer over-read occurs during network traffic analysis operations where tcpdump processes BGP messages to extract routing information for network monitoring and debugging purposes. The flaw enables attackers to craft malicious BGP messages that can trigger memory access violations when the parser attempts to read beyond allocated buffer boundaries.
The technical implementation of this vulnerability stems from inadequate input validation within the BGP attribute parsing logic. When tcpdump encounters an MP_REACH_NLRI attribute in a BGP message, the bgp_attr_print() function fails to properly verify the length of the attribute data before attempting to read from memory locations beyond the intended buffer limits. This condition creates a scenario where a carefully constructed malicious BGP packet can cause the tcpdump process to access invalid memory addresses, potentially leading to application crashes or, in more sophisticated attack scenarios, arbitrary code execution. The vulnerability specifically affects the handling of Multi-Protocol Reachable Network Layer Reachability Information attributes that are commonly used in BGP implementations for advertising routes across different network protocols.
From an operational perspective, this vulnerability poses significant risks to network monitoring infrastructure that relies on tcpdump for traffic analysis. Network administrators and security professionals who use tcpdump to monitor BGP traffic for security events, troubleshooting, or network visibility purposes are at risk when systems are running vulnerable versions of the software. The impact extends beyond simple denial of service as the buffer over-read could potentially be exploited to execute malicious code on systems running affected tcpdump versions. The attack vector requires an attacker to have the ability to inject or redirect BGP messages toward a target system running vulnerable tcpdump, making it particularly concerning for network operators who do not properly filter or validate BGP traffic from external peers. This vulnerability aligns with CWE-125: Out-of-bounds Read which classifies buffer over-read conditions as a fundamental memory safety issue.
The operational impact of CVE-2018-16230 can manifest in various ways depending on the execution environment and attack methodology employed. Systems utilizing tcpdump for BGP monitoring may experience unexpected process termination or system instability when processing maliciously crafted BGP messages. Network infrastructure components that depend on tcpdump for traffic analysis and security monitoring could become unavailable or unreliable, potentially disrupting network operations. The vulnerability also presents potential for privilege escalation or information disclosure in scenarios where the buffer over-read could be manipulated to access sensitive memory regions. Organizations using tcpdump for security monitoring, network debugging, or compliance auditing are particularly vulnerable since these systems often run continuously and process large volumes of network traffic including potentially malicious BGP advertisements.
Mitigation strategies for CVE-2018-16230 focus primarily on immediate software updates and network segmentation approaches. The most effective solution involves upgrading tcpdump to version 4.9.3 or later where the buffer over-read has been patched through proper input validation and bounds checking in the bgp_attr_print() function. Network administrators should also implement BGP route filtering and access control lists to limit exposure to potentially malicious BGP advertisements from untrusted peers. Additional protective measures include deploying intrusion detection systems that can detect and block malformed BGP traffic patterns, implementing network monitoring to identify unusual BGP message characteristics, and establishing proper network segmentation to limit the impact of potential exploitation. The remediation process should also include comprehensive testing of updated tcpdump installations in staging environments to ensure compatibility with existing network monitoring workflows and security policies. Organizations should also consider implementing automated patch management processes to ensure timely deployment of security updates across all network monitoring infrastructure components. This vulnerability demonstrates the importance of maintaining current network security tooling and implementing robust input validation practices in network protocol parsers to prevent memory safety issues that could compromise system integrity and availability.