CVE-2016-7933 in macOS
Summary
by MITRE
The PPP parser in tcpdump before 4.9.0 has a buffer overflow in print-ppp.c:ppp_hdlc_if_print().
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Analysis
by VulDB Data Team • 05/16/2026
The vulnerability identified as CVE-2016-7933 represents a critical buffer overflow condition within the Point-to-Point Protocol (PPP) parser implementation of tcpdump network analysis tool. This flaw exists specifically in the print-ppp.c source file at the ppp_hdlc_if_print() function, which processes PPP frames during network packet capture and analysis operations. The vulnerability affects tcpdump versions prior to 4.9.0, making it a significant concern for network security professionals who rely on this widely-used packet analysis tool for network monitoring and troubleshooting activities. The buffer overflow occurs when the application processes malformed or specially crafted PPP frames that exceed the allocated buffer space, potentially leading to arbitrary code execution or application crashes.
The technical implementation of this vulnerability stems from inadequate input validation within the PPP frame parsing logic. When tcpdump encounters PPP frames during packet capture, it attempts to parse the frame headers and payload data using the ppp_hdlc_if_print() function. The flaw manifests when the parser does not properly bounds-check the incoming data against the allocated buffer size, allowing attackers to craft malicious PPP packets that can overwrite adjacent memory locations. This type of vulnerability falls under the Common Weakness Enumeration category CWE-121, which describes "Stack-based Buffer Overflow" conditions where insufficient bounds checking allows attackers to write beyond the allocated buffer boundaries. The vulnerability is particularly dangerous because it operates within a network analysis tool that typically runs with elevated privileges, potentially providing attackers with a pathway to execute arbitrary code on systems where tcpdump is installed.
The operational impact of CVE-2016-7933 extends beyond simple application instability, as it can enable remote code execution in scenarios where tcpdump is used in network monitoring environments. Network administrators who deploy tcpdump for traffic analysis, intrusion detection, or forensic purposes may find their systems compromised if malicious actors can inject specially crafted PPP frames into monitored network traffic. The vulnerability can be exploited through various attack vectors including man-in-the-middle scenarios, compromised network infrastructure, or by targeting systems that process untrusted network traffic. From an adversary perspective, this vulnerability aligns with ATT&CK technique T1059.007 for "Command and Scripting Interpreter: PowerShell" in cases where attackers can leverage the compromised tcpdump process to execute additional malicious payloads, though the primary attack vector is the buffer overflow itself.
Mitigation strategies for CVE-2016-7933 primarily involve upgrading to tcpdump version 4.9.0 or later, which contains the necessary patches to address the buffer overflow condition. Organizations should conduct comprehensive vulnerability assessments to identify systems running vulnerable versions of tcpdump and prioritize patch deployment across their network infrastructure. Additionally, network segmentation and access controls can help limit the potential impact of exploitation by restricting access to systems where tcpdump is deployed. Security monitoring should include detection of unusual packet patterns that might indicate exploitation attempts, and network administrators should implement proper input validation and bounds checking measures in any custom network analysis implementations. The vulnerability serves as a reminder of the critical importance of maintaining up-to-date network security tools and the potential consequences of running legacy software in production environments where network traffic analysis is performed.