CVE-2013-4930 in Wireshark
Summary
by MITRE
The dissect_dvbci_tpdu_hdr function in epan/dissectors/packet-dvbci.c in the DVB-CI dissector in Wireshark 1.8.x before 1.8.9 and 1.10.x before 1.10.1 does not validate a certain length value before decrementing it, which allows remote attackers to cause a denial of service (assertion failure and application exit) via a crafted packet.
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Analysis
by VulDB Data Team • 05/20/2021
The vulnerability identified as CVE-2013-4930 represents a critical denial of service flaw within Wireshark's DVB-CI dissector component. This issue affects versions 1.8.x prior to 1.8.9 and 1.10.x prior to 1.10.1, where the dissect_dvbci_tpdu_hdr function fails to properly validate length parameters before performing decrement operations. The flaw resides in the packet-dvbci.c file within the epan/dissectors directory, specifically targeting the handling of DVB-CI (Digital Video Broadcasting - Common Interface) protocol packets. The DVB-CI protocol is commonly used in digital television broadcasting systems to enable conditional access and provide interactive services through set-top boxes and similar devices.
The technical implementation of this vulnerability stems from improper input validation within the dissector logic. When processing crafted DVB-CI packets, the dissect_dvbci_tpdu_hdr function attempts to decrement a length value without first verifying that this value remains within acceptable bounds. This validation failure creates a scenario where an attacker can construct malicious packets that, when processed by Wireshark, trigger an assertion failure. The assertion failure occurs because the decrement operation results in an invalid state that violates the program's internal assumptions about data integrity. When such a condition is encountered, the application terminates abruptly rather than gracefully handling the malformed input, leading to a complete denial of service for the network monitoring capabilities.
The operational impact of this vulnerability extends beyond simple service disruption, as it can be exploited remotely to compromise network monitoring infrastructure. Network administrators who rely on Wireshark for traffic analysis and security monitoring face significant risks when encountering malicious DVB-CI traffic, particularly in environments where broadcast television signals might be intercepted or where legacy DVB-CI equipment exists. The vulnerability can be particularly dangerous in security operations centers where continuous network monitoring is essential, as a single malicious packet could cause complete application shutdown and potentially interrupt critical security analysis processes. This flaw also represents a potential vector for bypassing network security measures, as the application crash could be used to obscure legitimate network activity or disrupt security auditing processes.
Mitigation strategies for CVE-2013-4930 focus primarily on immediate software updates and implementation of defensive network practices. The most effective solution involves upgrading to Wireshark versions 1.8.9 or 1.10.1 and later, which contain the necessary patches to properly validate length parameters before decrement operations. Network administrators should also implement packet filtering rules to prevent suspicious DVB-CI traffic from reaching monitoring systems, particularly in environments where such traffic is not expected. Additionally, deploying intrusion detection systems with signature-based detection for this specific vulnerability can provide early warning of exploitation attempts. The vulnerability aligns with CWE-129, which addresses improper validation of array indices, and represents a classic example of how inadequate input validation can lead to application instability and denial of service conditions. From an ATT&CK framework perspective, this vulnerability falls under the T1499.004 technique for Network Denial of Service, demonstrating how protocol-specific flaws can be weaponized to compromise availability of network monitoring tools.