CVE-2017-13047 in macOS
Summary
by MITRE
The ISO ES-IS parser in tcpdump before 4.9.2 has a buffer over-read in print-isoclns.c:esis_print().
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 12/04/2025
The vulnerability identified as CVE-2017-13047 represents a critical buffer over-read flaw within the tcpdump network analysis tool that affects versions prior to 4.9.2. This issue resides within the ISO ES-IS (End System to Intermediate System) protocol parser implementation, specifically in the print-isoclns.c source file where the esis_print() function executes. The flaw manifests when tcpdump processes network packets containing ISO ES-IS protocol data, creating a scenario where the parser attempts to read beyond the boundaries of allocated memory buffers. This over-read condition occurs because the parser does not properly validate the length of incoming protocol data before attempting to access memory locations beyond the intended buffer limits, potentially leading to unpredictable behavior and system instability.
The technical nature of this vulnerability places it squarely within the CWE-125 category of "Out-of-bounds Read" as defined by the Common Weakness Enumeration framework. This weakness occurs when a program reads data past the end of a buffer, which can result in information disclosure, application crashes, or potentially more severe consequences depending on how the read data is subsequently processed. The ATT&CK framework categorizes this type of vulnerability under the T1059.007 technique of "Command and Scripting Interpreter: PowerShell" in contexts where such memory corruption could be exploited to execute arbitrary code, though the direct exploitation pathway requires additional conditions. The vulnerability specifically affects the network packet parsing functionality of tcpdump, which is widely used for network traffic analysis and troubleshooting across various operating systems and network environments.
The operational impact of CVE-2017-13047 extends beyond simple application instability to potentially compromise network monitoring capabilities and system security. When an attacker can manipulate network traffic to trigger this buffer over-read condition, they may cause tcpdump to crash or behave unpredictably, leading to denial of service against network monitoring systems that rely on this tool. In environments where tcpdump is used for security monitoring, intrusion detection, or network forensic analysis, such a vulnerability could create gaps in security coverage. The over-read condition might also expose sensitive memory contents to unauthorized parties, potentially revealing system information, credentials, or other confidential data that resides in memory adjacent to the affected buffer. This makes the vulnerability particularly concerning for security-sensitive environments where tcpdump is deployed for network traffic inspection and analysis.
Mitigation strategies for CVE-2017-13047 primarily focus on updating tcpdump to version 4.9.2 or later, which contains the necessary patches to address the buffer over-read issue. System administrators should prioritize patching all instances of tcpdump across their network infrastructure, particularly those monitoring critical network segments or serving as security monitoring tools. Additional defensive measures include implementing network segmentation to limit exposure to potentially malicious traffic, configuring tcpdump to process only trusted network traffic when possible, and monitoring for abnormal tcpdump behavior that might indicate exploitation attempts. Organizations should also consider implementing network traffic filtering rules to prevent malformed ISO ES-IS packets from reaching systems running tcpdump, though this approach may impact legitimate network traffic analysis. The vulnerability demonstrates the importance of maintaining up-to-date network security tools and the potential consequences of failing to apply security patches in time, as even widely used tools like tcpdump can contain critical flaws that affect network security operations.