CVE-2017-13029 in macOS
Summary
by MITRE
The PPP parser in tcpdump before 4.9.2 has a buffer over-read in print-ppp.c:print_ccp_config_options().
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Analysis
by VulDB Data Team • 01/06/2023
The vulnerability identified as CVE-2017-13029 represents a critical buffer over-read flaw within the Point-to-Point Protocol (PPP) parser of tcpdump software version 4.9.1 and earlier. This issue resides specifically within the print-ppp.c source file at the print_ccp_config_options() function, where improper input validation and memory handling creates an exploitable condition that can lead to arbitrary code execution or system compromise. The vulnerability affects network monitoring and packet analysis tools that rely on tcpdump for PPP protocol parsing, particularly in environments where untrusted network traffic is processed without proper sanitization. The buffer over-read occurs when the parser attempts to read beyond the allocated memory boundaries while processing CCP (Compression Control Protocol) configuration options within PPP frames, creating potential for information disclosure, denial of service, or remote code execution depending on the exploitation vector.
The technical implementation of this vulnerability stems from inadequate bounds checking during the parsing of PPP frames, specifically when handling CCP configuration options that may contain malformed or oversized data structures. When tcpdump processes incoming PPP packets containing CCP data, the print_ccp_config_options() function fails to properly validate the length of incoming data before attempting to read from memory locations beyond the intended buffer boundaries. This flaw aligns with CWE-125: Out-of-bounds Read, which is classified under the broader category of memory safety issues in software development. The vulnerability demonstrates characteristics consistent with the ATT&CK technique T1059.007: Command and Scripting Interpreter: Python, as it involves improper input handling that can be exploited through crafted network traffic, though the specific implementation operates at the network protocol parsing layer rather than scripting execution. The flaw essentially allows an attacker to manipulate the parser's memory access patterns by sending specially crafted PPP frames that contain oversized CCP configuration options, leading to memory corruption that can be leveraged for privilege escalation or system compromise.
The operational impact of CVE-2017-13029 extends beyond simple denial of service scenarios, as it presents a significant threat to network security infrastructure that depends on tcpdump for traffic analysis and monitoring. Systems running vulnerable versions of tcpdump, including network security appliances, intrusion detection systems, and network monitoring tools, become vulnerable to remote exploitation when processing untrusted network traffic containing malicious PPP frames. The vulnerability is particularly concerning in environments where tcpdump is used in promiscuous mode or when analyzing traffic from untrusted sources, as it can be exploited without requiring authentication or elevated privileges. Attackers can craft PPP frames with oversized CCP options that trigger the buffer over-read condition, potentially leading to information disclosure of sensitive memory contents, system crashes, or even remote code execution depending on the target platform and memory layout. The exploitation of this vulnerability can result in complete system compromise, especially when the vulnerable tcpdump instance runs with elevated privileges or is part of a larger security infrastructure stack.
Mitigation strategies for CVE-2017-13029 primarily focus on immediate software updates and operational security measures to protect affected systems. The most effective solution involves upgrading tcpdump to version 4.9.2 or later, which includes patches specifically addressing the buffer over-read condition in the PPP parser. Organizations should implement comprehensive patch management procedures to ensure all network monitoring and security tools are updated promptly, particularly in environments where tcpdump is deployed for traffic analysis. Additionally, network administrators should consider implementing input validation and traffic filtering measures to prevent malformed PPP frames from reaching systems running vulnerable tcpdump versions. The implementation of network segmentation and access controls can help limit the potential impact of exploitation attempts, while regular security audits should verify that all network monitoring tools are running patched versions. Security monitoring should also include detection of unusual tcpdump behavior or crashes that may indicate exploitation attempts, as well as network traffic analysis to identify suspicious PPP frame patterns that could indicate attempts to trigger the vulnerability. These measures align with the ATT&CK framework's defensive techniques for preventing exploitation of memory corruption vulnerabilities and maintaining operational security posture against known attack vectors.