CVE-2017-13019 in macOS
Summary
by MITRE
The PGM parser in tcpdump before 4.9.2 has a buffer over-read in print-pgm.c:pgm_print().
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Analysis
by VulDB Data Team • 12/05/2025
The vulnerability identified as CVE-2017-13019 represents a critical buffer over-read flaw within the Packet Generator Message (PGM) parser implementation of tcpdump network analysis tool. This issue specifically affects versions prior to 4.9.2 and occurs in the print-pgm.c source file at the pgm_print() function, where insufficient input validation leads to memory access violations that can be exploited by malicious actors. The vulnerability stems from the parser's failure to properly validate packet header lengths and data boundaries before attempting to read from memory regions, creating an opportunity for attackers to trigger undefined behavior through crafted network packets.
The technical nature of this vulnerability aligns with CWE-125, which describes out-of-bounds read conditions where a program attempts to read memory beyond the allocated buffer boundaries. In the context of tcpdump, this flaw manifests when processing PGM protocol packets that contain malformed header information or truncated data structures. The parser does not adequately verify that the expected data length matches the actual packet content, allowing an attacker to craft packets that cause the pgm_print() function to access memory locations beyond the intended buffer limits. This over-read condition can result in information disclosure, application crashes, or potentially more severe consequences depending on the execution environment and memory layout.
The operational impact of CVE-2017-13019 extends beyond simple denial of service scenarios, as it creates potential attack vectors that align with several tactics outlined in the MITRE ATT&CK framework. An attacker could leverage this vulnerability to conduct reconnaissance activities by causing application instability or to perform information gathering through memory dumps that might reveal sensitive data from adjacent memory regions. The vulnerability affects tcpdump installations across various operating systems where the tool is deployed for network monitoring and packet analysis, making it particularly concerning for security operations centers and network administrators who rely on tcpdump for intrusion detection and network forensics. The issue is especially dangerous in environments where tcpdump is used in automated monitoring systems or integrated with other security tools that depend on stable packet parsing functionality.
Mitigation strategies for this vulnerability center around immediate version updates to tcpdump 4.9.2 or later, which contain the necessary code modifications to properly validate packet boundaries and prevent over-read conditions. Network administrators should also implement additional monitoring to detect unusual packet patterns that might indicate exploitation attempts, while considering network segmentation and access controls to limit exposure. The fix typically involves adding proper input validation checks that ensure packet header lengths are verified against available data before any memory access operations occur. Organizations should also conduct vulnerability assessments to identify systems running affected tcpdump versions and establish patch management procedures to maintain current security postures. Additionally, implementing network intrusion detection systems with signature-based detection for known PGM protocol anomalies can provide additional defense-in-depth measures against potential exploitation attempts.