CVE-2017-13038 in macOS
Summary
by MITRE
The PPP parser in tcpdump before 4.9.2 has a buffer over-read in print-ppp.c:handle_mlppp().
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Analysis
by VulDB Data Team • 12/04/2025
The vulnerability identified as CVE-2017-13038 resides within the Point-to-Point Protocol (PPP) parser implementation of tcpdump version 4.9.1 and earlier. This issue manifests as a buffer over-read condition that occurs during the processing of PPP frames, specifically within the handle_mlppp() function located in the print-ppp.c source file. The flaw represents a critical security weakness that can potentially be exploited by remote attackers to execute arbitrary code or cause denial of service conditions on systems running vulnerable versions of tcpdump.
The technical nature of this vulnerability stems from inadequate input validation and bounds checking within the PPP frame parsing logic. When tcpdump processes incoming PPP frames containing malformed or specially crafted data, the handle_mlppp() function fails to properly validate the length of data structures before accessing memory regions. This allows an attacker to construct malicious PPP frames that cause the parser to read beyond the allocated buffer boundaries, potentially accessing sensitive memory locations or triggering memory corruption. The vulnerability is classified as a buffer over-read according to 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 to potentially enable remote code execution on affected systems. When tcpdump is run in promiscuous mode or when network traffic is captured on systems with vulnerable versions, attackers can craft malicious PPP frames that trigger the buffer over-read condition. This could lead to system crashes, arbitrary code execution, or information disclosure depending on the specific memory access patterns triggered by the over-read. The vulnerability is particularly concerning because tcpdump is widely deployed across network monitoring and security analysis environments where it often runs with elevated privileges, making successful exploitation potentially devastating.
Mitigation strategies for CVE-2017-13038 involve immediate patching of tcpdump installations to version 4.9.2 or later, which contains the necessary fixes for the buffer over-read condition. System administrators should also implement network segmentation and access controls to limit exposure to potentially malicious traffic, while monitoring for anomalous PPP frame patterns that might indicate exploitation attempts. The vulnerability aligns with ATT&CK technique T1059.007 for remote code execution and T1490 for denial of service, making it a significant concern for security operations centers monitoring network traffic. Organizations should also consider implementing network intrusion detection systems that can identify and block malicious PPP frames, while maintaining regular updates to all network analysis tools to prevent similar vulnerabilities from being exploited in their environments.