CVE-2017-13010 in macOS
Summary
by MITRE
The BEEP parser in tcpdump before 4.9.2 has a buffer over-read in print-beep.c:l_strnstart().
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Analysis
by VulDB Data Team • 12/05/2025
The vulnerability identified as CVE-2017-13010 resides within the BEEP protocol parser implementation in tcpdump versions prior to 4.9.2. This issue manifests as a buffer over-read condition that occurs during the processing of BEEP (Blocks Extensible Exchange Protocol) traffic within network packet captures. The specific location of the vulnerability is within the print-beep.c source file at the l_strnstart() function, which handles string operations during protocol parsing. The BEEP protocol is commonly used for application layer communication and is often encountered in network monitoring scenarios where tcpdump is employed to analyze traffic patterns. This vulnerability represents a critical security flaw that could potentially be exploited by malicious actors to disrupt network monitoring operations or gain unauthorized access to system resources.
The technical flaw stems from improper input validation and boundary checking within the l_strnstart() function. When tcpdump processes BEEP protocol packets, the parser fails to adequately validate the length of string data being processed, leading to a situation where the code attempts to read beyond the allocated buffer boundaries. This over-read condition occurs because the parser does not properly check if the string length exceeds the available buffer space before performing memory access operations. The vulnerability is particularly concerning as it can be triggered by malformed BEEP packets that contain oversized or malformed string fields, which could be crafted by an attacker to exploit this memory access issue. This type of buffer over-read vulnerability falls under the common weakness enumeration CWE-125, which specifically addresses out-of-bounds read conditions in software implementations.
The operational impact of this vulnerability extends beyond simple denial of service scenarios. An attacker who can craft malicious BEEP packets could potentially exploit this buffer over-read to cause tcpdump to crash or behave unpredictably, thereby disrupting network monitoring and analysis capabilities. In environments where tcpdump is used for critical network security monitoring, such as intrusion detection systems or forensic analysis, this vulnerability could create significant operational risks. The exploitation of this vulnerability could also potentially lead to information disclosure or privilege escalation depending on the execution context and system configuration. Security professionals monitoring network traffic with tcpdump would face potential blind spots in their monitoring capabilities when encountering malicious BEEP traffic that triggers this specific buffer over-read condition. The vulnerability demonstrates the importance of proper input validation in network protocol parsers, as even seemingly benign protocol handling code can become a vector for serious security incidents.
Mitigation strategies for CVE-2017-13010 primarily involve upgrading to tcpdump version 4.9.2 or later, which contains the necessary patches to address the buffer over-read issue. Organizations should prioritize updating their tcpdump installations, particularly in environments where network traffic analysis is critical for security operations. Additionally, network administrators should implement monitoring for unusual BEEP traffic patterns that might indicate exploitation attempts. The vulnerability highlights the importance of regular security updates and the need for comprehensive input validation in network protocol parsers. Security teams should also consider implementing network segmentation and access controls to limit the impact of potential exploitation attempts. This vulnerability serves as a reminder of the critical nature of protocol parsing security and the potential for seemingly minor implementation flaws to create significant security risks in network monitoring tools. The ATT&CK framework classification for this vulnerability would fall under the T1059.007 technique for command and scripting interpreter, as exploitation could potentially involve crafting malicious network traffic to trigger the buffer over-read condition during protocol analysis operations.