CVE-2017-11544 in tcpdump
Summary
by MITRE
tcpdump 4.9.0 has a Segmentation Violation in the compressed_sl_print function in print-sl.c:229:3.
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Analysis
by VulDB Data Team • 01/06/2021
The vulnerability identified as CVE-2017-11544 represents a critical segmentation fault within tcpdump version 4.9.0, specifically manifesting in the compressed_sl_print function located in the print-sl.c source file at line 229. This issue stems from improper handling of packet data during the processing of certain network protocols, creating a scenario where maliciously crafted network traffic could trigger a memory access violation. The flaw occurs when tcpdump attempts to parse and display compressed SLIP (Serial Line Internet Protocol) packets, which are commonly used in serial network connections and certain embedded systems. The segmentation violation indicates that the application attempts to access memory locations that are either unmapped or protected, leading to an abrupt program termination and potential system instability.
The technical root cause of this vulnerability lies in inadequate input validation and buffer management within the packet parsing routine. When tcpdump encounters a malformed or unexpected compressed SLIP packet, the compressed_sl_print function fails to properly validate the packet structure before attempting to dereference memory pointers. This creates a classic buffer overflow condition where the program attempts to read beyond allocated memory boundaries, resulting in a segmentation fault that crashes the application. The vulnerability is classified as a memory corruption issue and maps to CWE-125: Out-of-bounds Read, which is a fundamental weakness in data handling that allows attackers to manipulate memory access patterns. This type of vulnerability falls under the category of remote code execution risks when exploited in network monitoring contexts.
The operational impact of CVE-2017-11544 extends beyond simple application crashes, particularly in environments where tcpdump serves as a critical network monitoring tool. Network administrators and security professionals who rely on tcpdump for packet analysis may find their monitoring systems becoming unreliable when processing malicious traffic, potentially creating blind spots in network security monitoring. The vulnerability affects systems running tcpdump 4.9.0 and earlier versions, which were widely deployed across enterprise networks, embedded systems, and security monitoring infrastructure. In a broader threat landscape context, this vulnerability aligns with ATT&CK technique T1046: Network Service Scanning, as attackers could potentially use this flaw to disrupt network monitoring capabilities or to identify vulnerable systems within a network. The crash condition could also be leveraged as part of a denial-of-service attack against network monitoring infrastructure, particularly in environments where tcpdump is used for continuous network traffic analysis.
Mitigation strategies for this vulnerability should prioritize immediate patching of tcpdump installations to versions 4.9.1 or later, which contain the necessary code modifications to properly validate packet structures before memory access. System administrators should implement network segmentation and access controls to limit exposure of tcpdump instances to untrusted network traffic. Additional protective measures include deploying network monitoring tools with built-in input validation and implementing intrusion detection systems that can identify and alert on malformed packet traffic. Organizations should also consider implementing network traffic filtering rules that can prevent suspicious packet patterns from reaching tcpdump processing components. The vulnerability demonstrates the importance of robust input validation in network security tools and highlights the need for continuous security testing of packet parsing routines. Security teams should conduct regular vulnerability assessments of network monitoring tools to identify similar memory corruption issues that could compromise system availability and security monitoring capabilities.