CVE-2015-6243 in Wireshark
Summary
by MITRE
The dissector-table implementation in epan/packet.c in Wireshark 1.12.x before 1.12.7 mishandles table searches for empty strings, which allows remote attackers to cause a denial of service (application crash) via a crafted packet, related to the (1) dissector_get_string_handle and (2) dissector_get_default_string_handle functions.
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Analysis
by VulDB Data Team • 06/13/2022
The vulnerability identified as CVE-2015-6243 represents a critical denial of service flaw within Wireshark's dissector table implementation that affects versions 1.12.x prior to 1.12.7. This issue resides in the epan/packet.c file where the dissector table handling logic fails to properly process searches for empty string values. The vulnerability specifically impacts two core functions: dissector_get_string_handle and dissector_get_default_string_handle, which are essential components for packet protocol analysis and protocol dissection within the network traffic analysis tool.
The technical flaw stems from improper input validation and handling of empty string parameters within the dissector table lookup mechanisms. When a crafted packet containing malformed or empty string data is processed by Wireshark, the dissector functions attempt to search through the protocol table structures without adequate bounds checking or null pointer validation. This leads to memory access violations and subsequent application crashes, effectively rendering the network analysis tool unusable for the duration of the attack. The vulnerability operates at the protocol dissection layer where Wireshark processes and interprets network packet data, making it particularly dangerous as it can be triggered simply by analyzing malicious network traffic.
From an operational standpoint, this vulnerability poses significant risks to network security analysts, forensic investigators, and network administrators who rely on Wireshark for traffic analysis. Attackers can exploit this flaw by crafting specially designed packets that, when analyzed by an affected Wireshark instance, will cause the application to terminate unexpectedly. This denial of service attack can be particularly devastating in security operations centers where continuous monitoring is required, as it can disrupt ongoing network analysis activities and potentially mask malicious traffic patterns. The impact extends beyond simple service disruption to potentially compromising the integrity of network forensic investigations and security assessments.
The vulnerability aligns with CWE-121, which addresses stack-based buffer overflow conditions, and represents a classic example of improper input validation that leads to application instability. From an ATT&CK framework perspective, this vulnerability maps to the T1071.004 technique related to application layer protocol: DNS, as it affects the proper functioning of network analysis tools that process various protocols. The flaw demonstrates how seemingly benign input handling can create critical security implications in network analysis tools. Organizations should immediately update to Wireshark version 1.12.7 or later to mitigate this vulnerability, as the patch addresses the improper string handling in the dissector table functions. Additionally, network security teams should consider implementing network segmentation and access controls to limit exposure while updates are being deployed, particularly in environments where Wireshark is used for critical network monitoring and analysis tasks.