CVE-2017-13040 in macOS
Summary
by MITRE
The MPTCP parser in tcpdump before 4.9.2 has a buffer over-read in print-mptcp.c, several functions.
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Analysis
by VulDB Data Team • 12/04/2025
The vulnerability identified as CVE-2017-13040 represents a critical buffer over-read flaw within the Multipath TCP (MPTCP) parser implementation of tcpdump version 4.9.1 and earlier. This issue resides in the print-mptcp.c source file, which handles the parsing and display of MPTCP protocol packets during network traffic analysis. The vulnerability arises from insufficient input validation and boundary checking within the parser functions that process MPTCP options in TCP packets. When tcpdump encounters malformed or specially crafted MPTCP packets, the parser fails to properly validate the length of MPTCP options before attempting to read data beyond the allocated buffer boundaries, creating a scenario where adjacent memory regions can be accessed without proper authorization.
The technical exploitation of this vulnerability occurs when tcpdump processes network packets containing MPTCP options that exceed expected parameter lengths or contain malformed data structures. The buffer over-read condition manifests as the parser attempting to read memory locations that may contain sensitive information, potentially leading to information disclosure or system instability. This flaw falls under the CWE-125 vulnerability category, which specifically addresses out-of-bounds read conditions in software implementations. The vulnerability directly impacts the integrity and confidentiality of network traffic analysis operations since attackers could potentially craft malicious MPTCP packets that trigger the over-read condition and extract data from adjacent memory segments.
From an operational perspective, this vulnerability poses significant risks to network security monitoring and forensic analysis capabilities. Organizations relying on tcpdump for network traffic inspection and incident response activities face potential exposure to information leakage through the buffer over-read mechanism. The impact extends beyond simple data disclosure as the over-read could potentially reveal sensitive information about the system's memory layout, application state, or other confidential data structures. The vulnerability affects the availability of tcpdump as a reliable network analysis tool since the over-read condition could cause the application to crash or behave unpredictably when processing certain MPTCP packet sequences. This disruption in network monitoring capabilities creates gaps in security posture that attackers could exploit to evade detection or conduct more sophisticated network reconnaissance activities.
The remediation approach for CVE-2017-13040 requires immediate deployment of tcpdump version 4.9.2 or later, which includes patched implementations of the MPTCP parser functions in print-mptcp.c. Security administrators should prioritize updating network monitoring infrastructure to prevent exploitation of this vulnerability. Additionally, network segmentation and monitoring of MPTCP traffic should be implemented as defensive measures to detect potential exploitation attempts. The vulnerability demonstrates the importance of proper input validation in network protocol parsers and aligns with ATT&CK technique T1046 for network service scanning and T1071 for application layer protocol usage. Organizations should implement regular vulnerability assessments of network monitoring tools and maintain up-to-date security patches to prevent similar issues in other protocol parsers within network analysis frameworks. The fix addresses the root cause by implementing proper bounds checking and validation of MPTCP option lengths before memory access operations occur, ensuring that the parser operates within safe memory boundaries regardless of input data characteristics.