CVE-2017-13688 in macOS
Summary
by MITRE
The OLSR parser in tcpdump before 4.9.2 has a buffer over-read in print-olsr.c:olsr_print().
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Analysis
by VulDB Data Team • 12/05/2025
The vulnerability identified as CVE-2017-13688 represents a critical buffer over-read flaw within the OLSR protocol parser of tcpdump version 4.9.1 and earlier. This issue manifests in the print-olsr.c source file at the olsr_print() function, where insufficient input validation allows maliciously crafted OLSR packets to trigger memory access violations. The vulnerability falls under the category of improper input validation as classified by CWE-121, specifically involving buffer over-read conditions that can lead to unpredictable behavior and potential exploitation. The OLSR protocol, or Optimized Link State Routing, is a dynamic routing protocol used in mobile ad-hoc networks and wireless mesh networks, making this vulnerability particularly concerning for network infrastructure security.
The technical implementation of this vulnerability stems from the tcpdump parser's failure to properly validate the length of OLSR packet headers before attempting to read from memory locations beyond the allocated buffer boundaries. When tcpdump processes network traffic containing OLSR packets, the olsr_print() function performs iterative reads of packet data without adequate bounds checking against the actual packet length. This allows an attacker to craft OLSR packets with malformed headers that cause the parser to access memory locations that do not correspond to valid packet data, potentially leading to information disclosure, application crashes, or in more severe scenarios, code execution. The flaw operates at the network protocol parsing layer, making it particularly dangerous as it can be triggered simply by capturing network traffic containing maliciously formatted OLSR packets.
The operational impact of this vulnerability extends beyond simple application instability to potentially compromise network monitoring capabilities and overall system security. Network administrators who rely on tcpdump for traffic analysis and security monitoring may find their tools becoming unreliable or even exploitable by attackers who can craft specific OLSR packets to trigger the buffer over-read. This creates a significant risk for network security operations centers that depend on tcpdump for network traffic inspection, as the tool itself becomes a potential attack vector rather than a defensive mechanism. The vulnerability also affects systems that use tcpdump as part of larger security toolchains, potentially undermining the integrity of network forensic analysis and incident response activities. From an ATT&CK framework perspective, this vulnerability aligns with techniques involving protocol analysis manipulation and can be leveraged as part of initial access or persistence phases in network-based attacks.
Mitigation strategies for CVE-2017-13688 primarily focus on upgrading to tcpdump version 4.9.2 or later, where the buffer over-read issue has been resolved through proper input validation and bounds checking mechanisms. Network administrators should also implement network segmentation and access controls to limit exposure to potentially malicious OLSR traffic, particularly in environments where wireless mesh networks are deployed. Additional defensive measures include deploying network intrusion detection systems that can identify and block malformed OLSR packets, implementing proper network monitoring to detect unusual traffic patterns that may indicate exploitation attempts, and conducting regular security assessments of network monitoring tools to ensure they are not vulnerable to similar buffer over-read conditions. Organizations should also consider implementing network traffic filtering rules that can drop OLSR packets at network boundaries, reducing the attack surface for this specific vulnerability.