CVE-2017-13032 in macOS
Summary
by MITRE
The RADIUS parser in tcpdump before 4.9.2 has a buffer over-read in print-radius.c:print_attr_string().
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Analysis
by VulDB Data Team • 01/06/2023
The vulnerability identified as CVE-2017-13032 represents a critical buffer over-read flaw within the RADIUS protocol parser of tcpdump software versions prior to 4.9.2. This issue resides in the print-radius.c source file at the print_attr_string() function, where improper input validation allows attackers to manipulate packet data in ways that can cause the application to read beyond allocated memory boundaries. The RADIUS protocol is widely used for network access authentication, authorization, and accounting services, making this vulnerability particularly concerning for network infrastructure security. When tcpdump processes RADIUS packets, the flawed parsing logic does not adequately validate the length of attribute strings before attempting to read them, creating opportunities for maliciously crafted packets to trigger memory corruption.
The technical implementation of this vulnerability stems from inadequate boundary checking within the print_attr_string() function which handles the display of RADIUS attribute strings during packet capture analysis. Attackers can craft specially formatted RADIUS packets containing malformed attribute data that exceeds expected buffer limits, causing tcpdump to attempt reading memory locations beyond the allocated buffer space. This over-read condition can result in information disclosure, application crashes, or potentially more severe consequences depending on the memory layout and execution context. The vulnerability is classified under CWE-125 as an "Out-of-bounds Read" which represents a fundamental flaw in memory safety where programs access memory outside the bounds of allocated buffers. The issue demonstrates poor input validation practices that violate secure coding principles and can be leveraged by attackers to gain unauthorized access to system information or disrupt network monitoring operations.
The operational impact of CVE-2017-13032 extends beyond simple application instability to potentially compromise network security monitoring capabilities. Network administrators who rely on tcpdump for traffic analysis and security auditing may find their monitoring tools vulnerable to denial-of-service attacks or information leakage when processing malicious RADIUS traffic. Since tcpdump is commonly used in security operations centers and network troubleshooting environments, this vulnerability could enable attackers to disrupt critical network monitoring activities or potentially extract sensitive information from memory dumps. The vulnerability aligns with ATT&CK technique T1046 which involves network service scanning and can be exploited to gain insights into network infrastructure or to establish persistent monitoring capabilities. Organizations using tcpdump for network traffic analysis should consider this vulnerability as a potential attack vector that could compromise their security monitoring infrastructure and enable adversaries to evade detection or gain unauthorized access to network information.
Mitigation strategies for this vulnerability primarily involve upgrading tcpdump to version 4.9.2 or later where the buffer over-read issue has been resolved through proper input validation and boundary checking mechanisms. System administrators should also implement network segmentation and access controls to limit exposure to potentially malicious RADIUS traffic while monitoring for unusual packet patterns that might indicate exploitation attempts. Additional defensive measures include deploying network intrusion detection systems that can identify and block malformed RADIUS packets, implementing proper network access controls to restrict RADIUS service access, and maintaining updated security patches for all network monitoring tools. Organizations should also consider implementing network monitoring tools with more robust input validation and memory safety features to reduce the attack surface and provide additional layers of protection against similar vulnerabilities in network infrastructure tools. The fix implemented in tcpdump 4.9.2 demonstrates proper defensive programming practices that include bounds checking and input validation to prevent buffer over-read conditions, aligning with industry best practices for secure software development and vulnerability remediation.