CVE-2018-19625 in Wireshark
Summary
by MITRE
In Wireshark 2.6.0 to 2.6.4 and 2.4.0 to 2.4.10, the dissection engine could crash. This was addressed in epan/tvbuff_composite.c by preventing a heap-based buffer over-read.
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Analysis
by VulDB Data Team • 06/12/2023
The vulnerability identified as CVE-2018-19625 represents a critical heap-based buffer over-read condition within Wireshark's dissection engine that affected versions between 2.4.0 through 2.4.10 and 2.6.0 through 2.6.4. This flaw resides in the tvbuff_composite.c file within the epan directory of Wireshark's source code, where the packet dissection functionality processes captured network traffic data. The issue manifests when the dissection engine encounters malformed or specially crafted network packets that trigger an improper memory access pattern during protocol analysis. According to CWE-125, this vulnerability falls under the category of out-of-bounds read conditions where an attacker can cause the application to read memory locations beyond the bounds of allocated buffers, potentially leading to application instability and system crashes.
The technical exploitation of this vulnerability occurs during the packet analysis phase when Wireshark processes network captures containing malformed data structures. The heap-based buffer over-read happens because the dissection engine fails to properly validate buffer boundaries before accessing memory regions, allowing for potential memory corruption that can result in application termination. This type of vulnerability directly maps to ATT&CK technique T1059.007 which describes the use of command and scripting interpreter for execution, though in this case the impact is more focused on application stability rather than direct execution. The flaw essentially allows an attacker to craft network packets that, when processed by Wireshark, cause the application to attempt reading beyond the allocated memory space, resulting in a segmentation fault or crash.
The operational impact of this vulnerability extends beyond simple application instability to potentially affect network forensics and security analysis operations. When an analyst or security professional is using Wireshark to investigate network traffic, a single malicious packet could cause the entire application to terminate unexpectedly, potentially leading to loss of critical forensic data and disruption of ongoing security investigations. This vulnerability particularly affects environments where Wireshark is used for continuous network monitoring or incident response activities, as an attacker could remotely trigger a denial of service condition against network analysis tools. The crash condition prevents legitimate network traffic analysis from continuing, potentially masking the presence of actual malicious activity while the application restarts. Organizations relying on Wireshark for network security monitoring and packet analysis face significant operational risks, as this vulnerability could be exploited to disrupt security operations without necessarily providing direct access to underlying systems.
The mitigation strategy for CVE-2018-19625 involves updating to Wireshark versions that have addressed the heap-based buffer over-read in epan/tvbuff_composite.c. The fix implemented by the Wireshark development team specifically prevents the over-read condition by adding proper boundary checks before memory access operations. Network security teams should ensure all instances of Wireshark are updated to versions 2.4.11 or 2.6.5 and later, which contain the necessary patches. Additionally, organizations should implement network monitoring that can detect and alert on unusual packet patterns that might indicate exploitation attempts, while maintaining regular patch management procedures to address similar vulnerabilities. The vulnerability serves as a reminder of the importance of robust input validation in network analysis tools, particularly those that process untrusted network data from potentially hostile environments.