CVE-2019-1010220 in tcpdump
Summary
by MITRE
tcpdump.org tcpdump 4.9.2 is affected by: CWE-126: Buffer Over-read. The impact is: May expose Saved Frame Pointer, Return Address etc. on stack. The component is: line 234: "ND_PRINT((ndo, "%s", buf));", in function named "print_prefix", in "print-hncp.c". The attack vector is: The victim must open a specially crafted pcap file.
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Analysis
by VulDB Data Team • 08/30/2025
The vulnerability identified as CVE-2019-1010220 represents a critical buffer over-read condition within tcpdump version 4.9.2 that falls under the Common Weakness Enumeration category CWE-126. This flaw exists in the print-hncp.c source file at line 234 within the print_prefix function where the ND_PRINT macro is invoked with a format string that directly references the buf variable without proper bounds checking. The vulnerability occurs when tcpdump processes specially crafted pcap files that contain malformed hncp protocol data, creating a scenario where the application attempts to read beyond the allocated buffer boundaries. The technical implementation involves the function calling ND_PRINT with "%s" format specifier against a buffer that may not contain proper null termination, leading to potential information disclosure from adjacent memory locations.
The operational impact of this vulnerability extends beyond simple information disclosure as it can expose sensitive stack data including saved frame pointers and return addresses that are typically protected from direct access by normal program execution flows. This exposure creates potential attack surface for sophisticated adversaries who could leverage this information to bypass security mechanisms such as stack canaries, address space layout randomization, and other exploit mitigations that rely on memory layout unpredictability. The vulnerability's exploitation requires a specific attack vector where a victim must open a maliciously crafted pcap file, making it a targeted privilege escalation or information gathering threat rather than a widespread remote code execution vulnerability. The memory corruption occurs during protocol parsing when tcpdump attempts to display prefix information from the hncp protocol, which is commonly used in network configuration and routing protocols.
From a cybersecurity perspective, this vulnerability aligns with ATT&CK technique T1059.007 for execution through command-line interface and T1566 for social engineering via spearphishing attachments that could contain malicious pcap files. The flaw demonstrates poor input validation and memory management practices that are commonly addressed through secure coding guidelines such as those outlined in the CERT Secure Coding Standards. Organizations utilizing tcpdump for network analysis and packet capture operations face significant risk if they process untrusted pcap files, as the vulnerability could be exploited to extract sensitive information from memory that might contain cryptographic keys, session tokens, or other confidential data. The vulnerability's classification as CWE-126 indicates that the application fails to properly validate buffer boundaries during memory operations, which is a fundamental security principle that should be enforced through proper bounds checking and input sanitization.
Mitigation strategies for CVE-2019-1010220 should prioritize immediate patching of tcpdump installations to versions that address the buffer over-read condition in the print_prefix function. System administrators should implement strict file validation policies that prevent automatic processing of untrusted pcap files and establish network segmentation to limit the potential impact of successful exploitation attempts. Additional defensive measures include monitoring for suspicious packet capture file access patterns and implementing application whitelisting controls that restrict tcpdump execution to authorized users and environments. The vulnerability highlights the importance of regular security updates and the need for thorough code review processes that include memory safety checks, particularly in network protocol parsing functions that handle untrusted input data from network traffic captures. Organizations should also consider implementing network monitoring solutions that can detect and alert on suspicious tcpdump activity or unusual packet capture file processing patterns to provide additional layers of defense against potential exploitation attempts.