CVE-2014-6423 in Wireshark
Summary
by MITRE
The tvb_raw_text_add function in epan/dissectors/packet-megaco.c in the MEGACO dissector in Wireshark 1.10.x before 1.10.10 and 1.12.x before 1.12.1 allows remote attackers to cause a denial of service (infinite loop) via an empty line.
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Analysis
by VulDB Data Team • 02/21/2022
The vulnerability identified as CVE-2014-6423 resides within the MEGACO dissector component of Wireshark, specifically in the tvb_raw_text_add function located in epan/dissectors/packet-megaco.c. This flaw affects versions 1.10.x prior to 1.10.10 and 1.12.x prior to 1.12.1, representing a critical denial of service weakness that can be exploited remotely. The vulnerability manifests when processing MEGACO protocol packets, which are used for signaling in multimedia communication systems, particularly in VoIP and telephony applications where media gateway control is essential. The MEGACO protocol, also known as Megaco/H.248, is widely implemented in telecommunications infrastructure for controlling media gateways and managing session setup and teardown processes.
The technical flaw occurs when the tvb_raw_text_add function encounters an empty line within MEGACO protocol data during packet analysis. This specific condition triggers an infinite loop within the dissector logic, causing the Wireshark application to become unresponsive and consume excessive CPU resources. The vulnerability stems from inadequate input validation and boundary checking within the text processing routines that handle raw data from network packets. When an empty line is processed, the function fails to properly terminate its loop structure, resulting in continuous iteration that can only be stopped by manual intervention or system restart. This behavior represents a classic denial of service scenario where legitimate network traffic analysis is disrupted, effectively preventing network administrators from monitoring or troubleshooting network communications.
The operational impact of this vulnerability extends beyond simple service disruption, as it can severely compromise network monitoring capabilities and incident response procedures. Network administrators who rely on Wireshark for real-time traffic analysis and troubleshooting may find their monitoring tools become unresponsive when processing maliciously crafted MEGACO packets. This vulnerability can be particularly dangerous in production environments where network visibility is critical for maintaining service quality and identifying security incidents. The infinite loop condition can affect not only the specific Wireshark instance but also potentially impact the entire system if the application consumes all available CPU resources, leading to cascading effects on network performance and system stability. From a cybersecurity perspective, this vulnerability aligns with attack patterns described in the MITRE ATT&CK framework under the T1499 category for network denial of service, specifically targeting network monitoring tools that are essential for security operations.
The root cause of this vulnerability can be mapped to CWE-835, which describes the weakness of an infinite loop or other looping construct that does not terminate properly. This weakness typically occurs when loop termination conditions are not correctly implemented or validated, particularly in protocols that process variable-length data structures. The vulnerability demonstrates how protocol-specific parsing functions can be exploited when input validation is insufficient, particularly in handling edge cases such as empty lines or null data sequences. The flaw represents a failure in defensive programming practices where boundary conditions are not properly considered during the development of dissectors for complex protocols like MEGACO that may contain various data formats and structures. Organizations using Wireshark for network security monitoring should consider this vulnerability as part of their broader security posture assessment, particularly in environments where network traffic analysis is critical for maintaining operational continuity and security incident response capabilities. The recommended mitigation involves updating to the patched versions of Wireshark where the infinite loop condition has been addressed through proper termination logic and input validation within the affected dissector functions.