CVE-2017-13042 in macOS
Summary
by MITRE
The HNCP parser in tcpdump before 4.9.2 has a buffer over-read in print-hncp.c:dhcpv6_print().
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Analysis
by VulDB Data Team • 09/08/2024
The vulnerability identified as CVE-2017-13042 represents a critical buffer over-read flaw within the HNCP protocol parser of tcpdump software version 4.9.1 and earlier. This issue specifically manifests in the print-hncp.c source file at the dhcpv6_print() function, where insufficient input validation allows maliciously crafted network packets to trigger unauthorized memory access patterns. The HNCP protocol, which stands for Host Name and Configuration Protocol, is designed to facilitate network configuration and host name resolution within IPv6 networks, making this vulnerability particularly concerning for network infrastructure monitoring tools.
The technical implementation of this buffer over-read occurs when tcpdump processes network packets containing HNCP data structures that are malformed or contain unexpected data lengths. During packet analysis, the dhcpv6_print() function attempts to parse DHCPv6 options within HNCP messages without proper bounds checking, leading to memory access beyond allocated buffer boundaries. This flaw can be exploited by attackers who craft specially formatted network packets containing malformed HNCP data, potentially causing the tcpdump application to read memory locations that do not belong to the intended buffer region. The vulnerability falls under CWE-125, which specifically addresses out-of-bounds read conditions in software implementations.
From an operational impact perspective, this vulnerability poses significant risks to network monitoring and security operations. When tcpdump is deployed in production environments for network traffic analysis, intrusion detection systems, or security monitoring, an attacker could leverage this flaw to cause application crashes, leading to denial of service conditions that disrupt network visibility. Additionally, the buffer over-read could potentially expose sensitive memory contents to unauthorized parties, creating information disclosure risks. The vulnerability's exploitation requires minimal network access and can be performed through standard network packet injection techniques, making it particularly dangerous in environments where tcpdump is used for continuous network monitoring.
The security implications extend beyond simple service disruption to include potential privilege escalation and information leakage scenarios. Attackers could construct malicious packets that cause tcpdump to read memory addresses containing sensitive data such as authentication credentials, cryptographic keys, or system configuration information. This vulnerability aligns with ATT&CK technique T1046, which involves network service scanning and reconnaissance, and T1059, which encompasses command and scripting interpreters. Organizations using tcpdump for network analysis should consider this vulnerability as part of their broader security posture assessment, particularly in environments where network monitoring tools are deployed in sensitive network segments. The recommended mitigation involves upgrading to tcpdump version 4.9.2 or later, which includes proper bounds checking and input validation mechanisms that prevent the buffer over-read condition from occurring during packet processing operations.
This vulnerability demonstrates the critical importance of input validation in network protocol parsers and highlights the potential for seemingly benign network monitoring tools to become attack vectors when proper security controls are not implemented. The flaw serves as a reminder that network infrastructure tools must be rigorously tested against malformed inputs and that security patches should be applied promptly to prevent exploitation of known vulnerabilities in widely deployed network monitoring software.