CVE-2018-7326 in Wireshark
Summary
by MITRE
In Wireshark 2.4.0 to 2.4.4 and 2.2.0 to 2.2.12, epan/dissectors/packet-lltd.c had an infinite loop that was addressed by using a correct integer data type.
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Analysis
by VulDB Data Team • 02/10/2023
The vulnerability identified as CVE-2018-7326 represents a critical flaw in Wireshark's LLTD protocol dissector that could lead to denial of service conditions. This issue affected versions 2.4.0 through 2.4.4 and 2.2.0 through 2.2.12 of the popular network protocol analyzer. The problem specifically resided in the epan/dissectors/packet-lltd.c file which handles the parsing of Link Layer Topology Discovery protocol packets. The LLTD protocol is used for network topology discovery and is particularly relevant in windows networking environments where it helps devices identify their network neighbors and establish connections.
The technical root cause of this vulnerability stems from an improper integer data type usage within the dissector logic. When processing malformed LLTD packets, the dissector would enter an infinite loop due to incorrect handling of integer values during packet parsing operations. This condition occurred because the code failed to properly validate or constrain integer values during the parsing process, leading to a scenario where loop conditions could never be satisfied. The vulnerability was classified under CWE-128 as "Unsigned to Signed Conversion Error" which occurs when an unsigned integer is converted to a signed integer without proper bounds checking, potentially causing unexpected behavior in loop conditions.
The operational impact of this vulnerability is significant as it allows remote attackers to cause a denial of service condition on systems running affected versions of Wireshark. When a user opens a maliciously crafted packet capture file containing malformed LLTD data, the application will hang indefinitely in the infinite loop, consuming system resources and potentially causing the application to become unresponsive. This affects not only the analyst's ability to perform network analysis but also creates a potential vector for service disruption in environments where Wireshark is used for continuous monitoring. The vulnerability can be exploited through various attack vectors including malicious packet captures, network traffic captures, or even by manipulating network traffic during real-time analysis sessions.
Mitigation strategies for this vulnerability involve immediate upgrading to Wireshark versions 2.4.5 and 2.2.13 or later, which contain the necessary patches to address the integer data type handling issue. Network administrators should also implement proper network segmentation and monitoring to detect unusual traffic patterns that might indicate exploitation attempts. The fix implemented by the Wireshark development team involved correcting the integer data type usage in the LLTD dissector to ensure proper bounds checking and loop termination conditions. This aligns with ATT&CK technique T1499.001 which covers network denial of service attacks and demonstrates how protocol parsing vulnerabilities can be leveraged for service disruption. Organizations should also consider implementing automated patch management systems to ensure timely deployment of security updates and maintain awareness of similar vulnerabilities in other protocol dissectors within the application.