CVE-2019-9208 in Wireshark
Summary
by MITRE
In Wireshark 2.4.0 to 2.4.12 and 2.6.0 to 2.6.6, the TCAP dissector could crash. This was addressed in epan/dissectors/asn1/tcap/tcap.cnf by avoiding NULL pointer dereferences.
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Analysis
by VulDB Data Team • 07/26/2023
The vulnerability identified as CVE-2019-9208 represents a critical denial of service flaw within Wireshark's TCAP dissector functionality. This issue affects versions 2.4.0 through 2.4.12 and 2.6.0 through 2.6.6, where the dissector responsible for interpreting Transaction Capabilities Application Part protocol data could experience a complete system crash. The TCAP protocol serves as a fundamental component in telecommunications signaling systems, particularly within the SS7 (Signaling System No. 7) infrastructure that governs voice and data communication across mobile networks. The flaw manifests as a NULL pointer dereference condition that occurs when processing malformed or unexpected TCAP protocol packets, leading to an immediate application termination and system instability. This vulnerability directly maps to CWE-476 which identifies NULL pointer dereference as a common programming error that can result in application crashes and potential system compromise.
The technical implementation of this vulnerability stems from insufficient input validation within the TCAP dissector module located in epan/dissectors/asn1/tcap/tcap.cnf. When Wireshark encounters TCAP protocol data that does not conform to expected formatting standards or contains unexpected field values, the dissector fails to properly handle NULL references that occur during packet parsing operations. The dissector's inability to gracefully manage malformed input causes the application to immediately terminate execution, effectively rendering the network analysis tool unusable for network monitoring and troubleshooting activities. This particular flaw demonstrates how protocol parsing errors can be exploited to create denial of service conditions that impact network infrastructure analysis capabilities.
The operational impact of CVE-2019-9208 extends beyond simple application crashes to potentially disrupt critical network monitoring operations within telecommunications environments. Network administrators and security analysts who rely on Wireshark for traffic analysis, troubleshooting, and security incident response may experience complete tool failure when encountering malicious or malformed TCAP traffic. This vulnerability particularly affects environments where SS7 protocol monitoring is essential, such as mobile network operators, telecommunications infrastructure providers, and security research organizations conducting network analysis. The crash condition prevents further packet processing and can mask legitimate network issues, complicating diagnostic efforts and potentially allowing malicious actors to disrupt network monitoring activities without detection. From an ATT&CK framework perspective, this vulnerability aligns with T1499.004 - Endpoint Denial of Service, where the disruption occurs through application-level crashes rather than network-level attacks.
The mitigation strategy for this vulnerability involves updating to Wireshark versions 2.4.13 and 2.6.7 or later, where the NULL pointer dereference has been addressed through improved input validation and error handling mechanisms. The fix implemented in the epan/dissectors/asn1/tcap/tcap.cnf file ensures that the dissector properly validates pointer references before attempting to access memory locations, preventing the application crash that occurred in vulnerable versions. Network administrators should prioritize patching affected systems, particularly in environments where network monitoring tools are critical for operational continuity. Additionally, implementing network segmentation and traffic filtering policies can provide additional defense-in-depth measures to prevent exploitation of this vulnerability. Security teams should also consider monitoring for unusual traffic patterns that might indicate attempts to exploit this vulnerability, as the crash behavior could potentially be used to disrupt network analysis operations. The remediation process should include comprehensive testing of updated Wireshark installations to ensure that the fix does not introduce compatibility issues with existing network monitoring workflows and that the tool continues to accurately parse TCAP protocol data under normal operating conditions.