CVE-2018-9271 in Wireshark
Summary
by MITRE
In Wireshark 2.4.0 to 2.4.5 and 2.2.0 to 2.2.13, epan/dissectors/packet-multipart.c has a memory leak.
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Analysis
by VulDB Data Team • 02/26/2023
The vulnerability identified as CVE-2018-9271 represents a memory leak flaw within Wireshark's packet dissection functionality, specifically affecting versions ranging from 2.4.0 through 2.4.5 and 2.2.0 through 2.2.13. This issue resides in the epan/dissectors/packet-multipart.c file which handles the dissection of multipart MIME messages commonly found in email communications and web traffic. The memory leak occurs during the processing of malformed or specially crafted multipart messages that contain excessive or malformed boundaries, leading to improper memory deallocation in the dissection engine. This vulnerability falls under the CWE-401 category of Improper Release of Memory Before Removing Last Reference, which is a fundamental memory management flaw that can lead to resource exhaustion and system instability.
The technical implementation of this vulnerability stems from how Wireshark's dissectors handle multipart message boundaries during packet analysis. When processing multipart messages, the dissectors allocate memory to store boundary information and message components, but fail to properly release this memory when encountering certain malformed boundary sequences or when the dissection process terminates prematurely. This memory allocation issue is particularly concerning because Wireshark operates as a network protocol analyzer that continuously processes large volumes of network traffic, making it susceptible to gradual memory consumption that can eventually lead to application crashes or system performance degradation. The flaw manifests when the multipart dissector encounters boundary strings that exceed expected lengths or contain unusual character sequences that trigger the memory allocation path without proper cleanup mechanisms.
The operational impact of CVE-2018-9271 extends beyond simple resource consumption, as it creates potential denial of service conditions that can compromise network analysis capabilities. When exploited, this vulnerability allows attackers to craft specially formatted network packets that, when analyzed by Wireshark, cause the application to consume increasing amounts of memory over time. This progressive memory consumption can lead to application instability, crashes, or complete system resource exhaustion, particularly in environments where Wireshark is continuously monitoring high-volume network traffic. The vulnerability is particularly dangerous in network security operations centers where Wireshark is used for continuous monitoring, as it can cause legitimate network analysis tools to become unavailable during critical security events. From an attacker perspective, this vulnerability aligns with ATT&CK technique T1490 for Resource Exhaustion, where the attacker consumes system resources to render systems unusable.
Mitigation strategies for CVE-2018-9271 focus on immediate version upgrades to Wireshark 2.4.6 or 2.2.14, which contain the necessary patches to address the memory leak in the multipart dissector. Organizations should prioritize patch management to ensure all instances of Wireshark are updated to versions that have resolved this vulnerability. Additionally, network administrators can implement monitoring solutions to detect abnormal memory usage patterns in Wireshark processes, providing early warning of potential exploitation attempts. The patch implementation addresses the root cause by ensuring proper memory deallocation when processing multipart messages, particularly those with malformed boundaries or excessive length sequences. Security teams should also consider implementing network traffic filtering rules to limit the impact of potentially malicious multipart traffic, though the most effective solution remains the application of the official patches provided by the Wireshark development team.