CVE-2015-8718 in Wireshark
Summary
by MITRE
Double free vulnerability in epan/dissectors/packet-nlm.c in the NLM dissector in Wireshark 1.12.x before 1.12.9 and 2.0.x before 2.0.1, when the "Match MSG/RES packets for async NLM" option is enabled, allows remote attackers to cause a denial of service (application crash) via a crafted packet.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 07/02/2022
The CVE-2015-8718 vulnerability represents a critical double free error within the Network Lock Manager (NLM) dissector component of Wireshark, specifically in the packet-nlm.c file. This flaw exists in versions 1.12.x prior to 1.12.9 and 2.0.x prior to 2.0.1, making it a widespread issue affecting multiple stable release lines of the network protocol analyzer. The vulnerability manifests when the "Match MSG/RES packets for async NLM" option is enabled, which is a feature designed to correlate NLM messages and responses for better protocol analysis. The double free condition occurs during the processing of malformed NLM packets that exploit memory management flaws in the dissector's handling of protocol data structures.
The technical implementation of this vulnerability involves improper memory deallocation patterns where the same memory block gets freed twice during the processing of a crafted NLM packet. This occurs when the dissector encounters specially constructed packets that trigger a code path where allocated memory resources are released multiple times before being reassigned or used again. The flaw stems from inadequate input validation and memory management within the NLM protocol parsing logic, specifically when handling asynchronous NLM message-response correlation. The double free condition creates a state where the memory allocator's internal data structures become corrupted, leading to undefined behavior that manifests as application instability.
From an operational perspective, this vulnerability presents a significant denial of service risk for Wireshark users who have the NLM packet matching feature enabled. Remote attackers can exploit this weakness by crafting specially formatted NLM packets that, when processed by the affected Wireshark versions, cause the application to crash and terminate unexpectedly. The impact extends beyond simple service disruption as it affects network analysis capabilities, potentially interrupting critical network monitoring and troubleshooting operations. Network security analysts and forensic investigators who rely on Wireshark for protocol analysis face potential operational disruptions when encountering malicious traffic that triggers this vulnerability.
The vulnerability aligns with CWE-415, which describes improper free errors in memory management, and demonstrates characteristics consistent with the ATT&CK technique T1498, specifically Denial of Service through resource exhaustion. Organizations using Wireshark for network monitoring, security analysis, or incident response may find their operational capabilities compromised when this vulnerability is exploited in the field. The attack vector requires only network access to send malicious packets to a target system running the vulnerable Wireshark version, making it particularly dangerous in environments where network traffic analysis is performed on potentially hostile networks. The remediation strategy involves updating to patched versions of Wireshark, specifically 1.12.9 or 2.0.1, and disabling the vulnerable NLM packet matching feature until the update is complete.
Mitigation approaches should include immediate deployment of the patched Wireshark versions, along with network segmentation to limit exposure to potentially malicious traffic. Security teams should also consider implementing network-based intrusion detection systems that can identify and block NLM protocol anomalies that may indicate exploitation attempts. The vulnerability underscores the importance of maintaining current security software versions and highlights the risks associated with enabling advanced protocol analysis features without proper input validation. Organizations should conduct vulnerability assessments to identify systems running vulnerable versions and implement comprehensive patch management procedures to prevent exploitation of similar memory corruption vulnerabilities in network analysis tools.