CVE-2018-14464 in tcpdump
Summary
by MITRE
The LMP parser in tcpdump before 4.9.3 has a buffer over-read in print-lmp.c:lmp_print_data_link_subobjs().
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Analysis
by VulDB Data Team • 01/03/2024
The vulnerability identified as CVE-2018-14464 represents a critical buffer over-read flaw within the Link Management Protocol (LMP) parser of tcpdump version 4.9.2 and earlier. This issue specifically manifests in the print-lmp.c source file at the lmp_print_data_link_subobjs() function, where improper input validation allows for memory access beyond allocated buffer boundaries. The vulnerability occurs during packet processing when tcpdump encounters malformed LMP packets that contain oversized or malformed data link subobjects, creating conditions where the parser attempts to read memory locations that are not part of the intended data structure. Such buffer over-read conditions can result in unpredictable behavior including program crashes, data corruption, or potentially exploitable memory access violations that may be leveraged by attackers to execute arbitrary code.
The technical implementation of this vulnerability stems from inadequate bounds checking within the LMP packet parsing logic. When tcpdump processes incoming network packets containing LMP data, the lmp_print_data_link_subobjs() function fails to properly validate the length of data link subobjects before attempting to read them into memory. This deficiency creates a classic buffer over-read scenario where the parser assumes a certain data structure size without verifying that the actual packet data conforms to expected parameters. The vulnerability is particularly concerning because LMP is used in various networking contexts including ATM and MPLS environments where tcpdump is commonly deployed for network monitoring and analysis. The lack of proper input sanitization means that an attacker who can inject maliciously crafted LMP packets into the network traffic can trigger this condition, potentially leading to denial of service or more severe exploitation outcomes depending on the execution environment.
From an operational impact perspective, this vulnerability poses significant risks to network monitoring infrastructure that relies on tcpdump for packet analysis. Network administrators and security professionals who use tcpdump for troubleshooting, security auditing, or network traffic analysis may find their monitoring tools become unstable or crash when processing maliciously crafted LMP packets. The vulnerability affects systems where tcpdump is actively monitoring networks containing LMP traffic, which includes various telecommunications and enterprise networking environments where ATM and MPLS protocols are deployed. The potential for denial of service represents a serious operational concern since network monitoring tools are typically expected to remain stable and available during critical network events. Additionally, the vulnerability may be exploited in conjunction with other attack vectors to gain unauthorized access to monitoring systems, particularly in environments where tcpdump is run with elevated privileges or in automated monitoring workflows.
Mitigation strategies for CVE-2018-14464 should prioritize immediate patching of tcpdump installations to version 4.9.3 or later, which contains the necessary fixes for the buffer over-read condition. System administrators should also implement network segmentation and access controls to limit exposure to potentially malicious LMP traffic, particularly in environments where tcpdump is actively monitoring untrusted network segments. Additional defensive measures include implementing network intrusion detection systems that can identify and block malformed LMP packets, configuring tcpdump to run with minimal privileges, and establishing robust monitoring for system crashes or unexpected behavior in network monitoring tools. The vulnerability aligns with CWE-125: "Out-of-bounds Read" and may be categorized under ATT&CK technique T1059.007: "Command and Scripting Interpreter: Python" when considering the potential for exploitation through automated network monitoring tool compromise. Organizations should also conduct regular vulnerability assessments of their network monitoring infrastructure to identify similar buffer over-read conditions in other network analysis tools and protocols, as this represents a common class of vulnerabilities in network protocol parsers that require consistent input validation and bounds checking mechanisms.