CVE-2017-13001 in macOS
Summary
by MITRE
The NFS parser in tcpdump before 4.9.2 has a buffer over-read in print-nfs.c:nfs_printfh().
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Analysis
by VulDB Data Team • 12/05/2025
The vulnerability identified as CVE-2017-13001 represents a critical buffer over-read flaw within the Network File System (NFS) parser implementation of tcpdump utility versions prior to 4.9.2. This issue specifically manifests in the print-nfs.c source file at the nfs_printfh() function, where improper input validation and memory handling allows for unauthorized data access beyond allocated buffer boundaries. The vulnerability arises from insufficient bounds checking when processing NFS file handle data structures, creating a scenario where maliciously crafted network packets can trigger memory corruption during packet analysis operations.
The technical execution of this vulnerability occurs when tcpdump processes Network File System traffic and encounters malformed NFS file handle data. The nfs_printfh() function fails to properly validate the length of incoming file handle data before attempting to read from memory locations beyond the intended buffer limits. This over-read condition can lead to information disclosure, as the parser may access and potentially expose sensitive data from adjacent memory regions. The flaw demonstrates characteristics consistent with CWE-129 Improper Validation of Array Index, where array indexing operations lack proper validation of input values against array boundaries, and CWE-125 Out-of-bounds Read, which describes situations where code reads data beyond the boundaries of allocated buffers.
From an operational perspective, this vulnerability poses significant risks to network monitoring and security analysis environments that rely on tcpdump for packet capture and analysis. Attackers can exploit this weakness by crafting malicious NFS packets that, when processed by vulnerable tcpdump instances, trigger the buffer over-read condition. The impact extends beyond simple information disclosure, as the over-read could potentially lead to denial of service conditions or even facilitate more sophisticated attacks depending on the specific memory layout and data exposure. The vulnerability affects systems where tcpdump is used for network traffic analysis, particularly in security operations centers, network troubleshooting environments, and forensic analysis workflows where NFS traffic is commonly encountered.
The exploitation of CVE-2017-13001 aligns with ATT&CK technique T1046 Network Service Scanning, where adversaries may leverage such vulnerabilities to identify and compromise network monitoring tools. Organizations using tcpdump for security monitoring should consider this vulnerability as part of their broader threat landscape assessment, particularly in environments where NFS services are active. The remediation strategy focuses on upgrading tcpdump to version 4.9.2 or later, which includes proper bounds checking and input validation mechanisms. Additional mitigations may involve network segmentation to limit NFS traffic exposure, implementing network access controls, and conducting regular vulnerability assessments to identify other potential buffer over-read conditions in network analysis tools. Security teams should also consider implementing intrusion detection systems that can detect anomalous NFS traffic patterns that might indicate exploitation attempts.