CVE-2018-7337 in Wireshark
Summary
by MITRE
In Wireshark 2.4.0 to 2.4.4, the DOCSIS protocol dissector could crash. This was addressed in plugins/docsis/packet-docsis.c by removing the recursive algorithm that had been used for concatenated PDUs.
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Analysis
by VulDB Data Team • 02/10/2023
The vulnerability identified as CVE-2018-7337 represents a critical denial of service flaw within Wireshark's DOCSIS protocol dissector functionality. This issue affected versions 2.4.0 through 2.4.4 of the popular network protocol analyzer, where the dissector exhibited unstable behavior when processing specific DOCSIS protocol data units. The DOCSIS protocol dissector is responsible for parsing and analyzing Data Over Cable Service Interface Specifications traffic, which is essential for troubleshooting and monitoring cable modem networks. The flaw manifested as a crash condition that could be triggered by maliciously crafted DOCSIS packets, potentially disrupting network analysis operations and compromising the availability of network monitoring tools.
The technical root cause of this vulnerability stems from an implementation flaw in the plugins/docsis/packet-docsis.c file where a recursive algorithm was employed for handling concatenated PDUs within the DOCSIS protocol. This recursive approach created a potential stack overflow condition when processing malformed or specially crafted DOCSIS packets containing concatenated protocol data units. The recursive algorithm lacked proper depth limiting or termination conditions, allowing attackers to craft packets that would cause the dissector to recursively call itself indefinitely until the system stack overflowed and the application crashed. This type of vulnerability aligns with CWE-674, which describes "Uncontrolled Recursion" and represents a classic example of how recursive algorithms without proper safeguards can lead to denial of service conditions.
The operational impact of CVE-2018-7337 extends beyond simple application crashes to potentially compromise network monitoring and security operations. Network administrators and security analysts who rely on Wireshark for network traffic analysis could experience unexpected disruptions when analyzing DOCSIS traffic, particularly in environments where cable modem networks are actively monitored. The vulnerability creates a potential attack vector where malicious actors could deliberately send crafted DOCSIS packets to crash network analysis tools, effectively preventing legitimate network monitoring activities. This disruption could be particularly problematic in security operations centers where continuous network monitoring is essential for threat detection and incident response activities, as outlined in the ATT&CK framework's methodology for network monitoring and analysis.
The remediation implemented for CVE-2018-7337 involved removing the problematic recursive algorithm from the DOCSIS dissector implementation and replacing it with an iterative approach for handling concatenated PDUs. This change eliminated the stack overflow vulnerability while maintaining the dissector's functionality for properly parsing DOCSIS protocol traffic. The fix demonstrates the importance of proper algorithm design in network security tools, particularly when handling potentially malicious input data. Organizations should ensure they update to Wireshark versions that include this fix to protect against potential exploitation of this vulnerability. The resolution also highlights the broader security principle that recursive algorithms require careful implementation with proper termination conditions and depth limits to prevent exploitation through resource exhaustion attacks. This vulnerability underscores the critical need for robust input validation and defensive programming practices in network protocol analysis tools that process potentially hostile network traffic.