CVE-2018-9256 in Wireshark
Summary
by MITRE
In Wireshark 2.4.0 to 2.4.5 and 2.2.0 to 2.2.13, the LWAPP dissector could crash. This was addressed in epan/dissectors/packet-lwapp.c by limiting the encapsulation levels to restrict the recursion depth.
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Analysis
by VulDB Data Team • 02/26/2023
The vulnerability identified as CVE-2018-9256 represents a critical denial of service flaw within Wireshark's LWAPP dissector functionality. This issue affected versions ranging from 2.4.0 through 2.4.5 and 2.2.0 through 2.2.13, creating a potential vector for attackers to disrupt network analysis operations. The LWAPP protocol dissector is responsible for parsing Lightweight Wireless Access Point Protocol traffic, which is commonly used in wireless network management and monitoring scenarios. The flaw manifested as a crash condition that could be triggered through malformed packet structures, specifically those with excessive encapsulation levels that led to uncontrolled recursion within the dissector logic.
The technical root cause of this vulnerability stems from inadequate input validation within the LWAPP dissector implementation. When processing packets containing nested encapsulation layers beyond the expected protocol limits, the dissector would recursively process these structures without proper depth limitations. This recursive processing behavior created a scenario where a maliciously crafted packet could cause the dissector to consume excessive system resources and ultimately result in application termination. The vulnerability aligns with CWE-674, which specifically addresses uncontrolled recursion in software implementations, and represents a classic example of insufficient recursion depth control in protocol parsing components.
The operational impact of CVE-2018-9256 extends beyond simple service disruption to encompass broader network monitoring and security analysis capabilities. Network security professionals who rely on Wireshark for wireless network troubleshooting, incident response, or security auditing could find their analysis tools rendered inoperative when encountering maliciously crafted LWAPP traffic. This disruption could occur in various operational contexts including enterprise network monitoring, wireless security assessments, and forensic analysis of network traffic. The vulnerability particularly affects environments where automated network analysis systems process untrusted traffic, as these systems could be exploited to cause sustained service disruption without requiring elevated privileges or specialized attack capabilities.
Mitigation strategies for this vulnerability center on implementing the fix introduced in epan/dissectors/packet-lwapp.c which establishes explicit limits on encapsulation levels to control recursion depth. This approach follows established security principles from the ATT&CK framework under the T1499 category of network denial of service, where the mitigation involves restricting resource consumption through input validation and depth limiting mechanisms. Organizations should immediately upgrade to Wireshark versions that include the patched dissector implementation, as the fix directly addresses the recursion control issue without introducing functional regressions. Additionally, network administrators should implement traffic filtering rules to prevent malicious LWAPP traffic from reaching systems running vulnerable Wireshark versions, though this represents a secondary mitigation measure since the primary fix resolves the core issue through proper protocol parsing controls.