CVE-2018-6836 in Wireshark
Summary
by MITRE
The netmonrec_comment_destroy function in wiretap/netmon.c in Wireshark through 2.4.4 performs a free operation on an uninitialized memory address, which allows remote attackers to cause a denial of service (application crash) or possibly have unspecified other impact.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 02/06/2023
The vulnerability identified as CVE-2018-6836 represents a critical memory management flaw within Wireshark's network protocol analyzer software. This issue resides in the netmonrec_comment_destroy function located in wiretap/netmon.c, where the application fails to properly initialize memory pointers before attempting to free them. The flaw manifests when processing network captures that contain specific malformed data structures, creating a scenario where the software attempts to release memory at an unpredictable location in memory. Such uninitialized memory addresses can point to arbitrary memory locations, potentially causing the application to crash when it attempts to execute the free operation. The vulnerability is particularly concerning because it can be exploited remotely through crafted packet captures, making it a significant threat to network monitoring operations that rely on Wireshark for traffic analysis. This type of memory corruption vulnerability directly relates to CWE-459, which describes incomplete cleanup issues in software, and represents a classic example of improper memory management that can lead to application instability.
The operational impact of CVE-2018-6836 extends beyond simple denial of service conditions, as the uninitialized memory access could potentially be leveraged for more sophisticated attacks depending on the execution environment. When an attacker successfully triggers this vulnerability through a malicious packet capture file, the application crash occurs due to the free operation being performed on an address that has not been properly initialized. This behavior aligns with ATT&CK technique T1499.001, which covers network denial of service attacks, and represents a significant risk to network security operations centers that depend on stable packet analysis tools. The vulnerability affects Wireshark versions through 2.4.4, indicating that organizations running these older versions face substantial risk, particularly in environments where network traffic analysis is performed on potentially malicious or untrusted data. The remote exploitation capability means that simply opening a maliciously crafted capture file could compromise the stability of the analysis environment, potentially disrupting critical network monitoring activities and exposing organizations to data loss or service interruption.
Mitigation strategies for CVE-2018-6836 primarily focus on immediate software updates and operational procedures to prevent exploitation. Organizations should prioritize upgrading to Wireshark versions 2.4.5 or later, where the memory management issue has been resolved through proper initialization of memory pointers before free operations. Additionally, implementing network monitoring policies that restrict the opening of untrusted packet captures can provide defense-in-depth protection against potential exploitation attempts. Security teams should also consider implementing sandboxing techniques when analyzing suspicious network traffic, ensuring that any potential exploitation attempts do not compromise the broader network infrastructure. The vulnerability demonstrates the importance of proper memory management practices in security-critical applications and highlights the necessity of thorough code review processes to identify similar issues in network analysis tools. Organizations should also establish regular patch management procedures to ensure timely deployment of security fixes, particularly for widely-used network analysis tools that serve as critical infrastructure components in cybersecurity operations.