CVE-2017-13027 in macOS
Summary
by MITRE
The LLDP parser in tcpdump before 4.9.2 has a buffer over-read in print-lldp.c:lldp_mgmt_addr_tlv_print().
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Analysis
by VulDB Data Team • 12/05/2025
The vulnerability identified as CVE-2017-13027 represents a critical buffer over-read flaw within the Link Layer Discovery Protocol (LLDP) parser functionality of tcpdump software version 4.9.1 and earlier. This issue manifests specifically within the print-lldp.c source file at the lldp_mgmt_addr_tlv_print() function, where improper input validation leads to memory access violations. The LLDP protocol serves as a critical network discovery mechanism that allows network devices to advertise their identity, configuration, and capabilities to neighboring devices, making it an essential component for network management and troubleshooting operations.
The technical implementation of this vulnerability stems from inadequate boundary checking during the parsing of LLDP management address TLV (Type-Length-Value) structures. When tcpdump processes network packets containing LLDP information, the parser fails to validate the length field of the management address TLV against the actual available buffer space. This allows an attacker to craft malicious LLDP packets with malformed TLV structures that cause the application to read beyond allocated memory boundaries. The buffer over-read occurs because the code assumes that the length field accurately represents the available data, without performing proper validation checks that would prevent reading past the intended buffer limits. This flaw directly maps to CWE-125, which describes out-of-bounds read vulnerabilities where an application accesses memory beyond the boundaries of a buffer.
The operational impact of this vulnerability extends beyond simple denial-of-service conditions, as it creates potential attack vectors for more sophisticated exploitation techniques. Network administrators who rely on tcpdump for network monitoring and analysis face significant risk when processing traffic containing malicious LLDP frames, as the over-read could potentially lead to application crashes, memory corruption, or even remote code execution depending on the specific memory layout and subsequent exploitation attempts. The vulnerability affects any system running tcpdump versions prior to 4.9.2, making it particularly concerning for enterprise network environments where packet capture and analysis tools are widely deployed. This issue aligns with ATT&CK technique T1046 which involves network service scanning and reconnaissance activities that can be amplified through malformed packet processing.
Mitigation strategies for CVE-2017-13027 primarily focus on immediate software updates to tcpdump version 4.9.2 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 LLDP traffic, particularly in critical network segments where tcpdump monitoring is actively deployed. Additional defensive measures include implementing network-based intrusion detection systems that can identify and block malformed LLDP packets, deploying tcpdump with restricted privileges to limit potential impact from exploitation, and establishing regular vulnerability assessment procedures to identify other potentially affected components. Network administrators should also consider implementing automated patch management processes to ensure timely deployment of security updates across all network monitoring infrastructure. The vulnerability demonstrates the importance of proper input validation in network protocol parsing libraries and highlights the need for comprehensive security testing of network analysis tools in production environments.