CVE-2017-9352 in Wireshark
Summary
by MITRE
In Wireshark 2.2.0 to 2.2.6 and 2.0.0 to 2.0.12, the Bazaar dissector could go into an infinite loop. This was addressed in epan/dissectors/packet-bzr.c by ensuring that backwards parsing cannot occur.
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Analysis
by VulDB Data Team • 12/07/2022
The vulnerability identified as CVE-2017-9352 represents a critical denial of service flaw within Wireshark's Bazaar version control system dissector. This issue affected versions ranging from 2.2.0 through 2.2.6 and 2.0.0 through 2.0.12, creating a scenario where the network protocol analyzer could become completely unresponsive during packet processing. The flaw specifically targeted the Bazaar dissector component responsible for parsing and analyzing Bazaar version control protocol traffic, which is commonly used in distributed software development environments.
The technical root cause of this vulnerability stems from inadequate input validation within the packet parsing logic. The dissector was susceptible to malformed Bazaar protocol packets that could trigger an infinite loop condition during backwards parsing operations. This occurs when the parser encounters specific packet structures that cause it to continuously iterate through the same data segments without making forward progress. The vulnerability aligns with CWE-835, which describes the weakness of infinite loops in software implementations where loop termination conditions are not properly enforced. The flaw demonstrates a classic example of insufficient boundary checking and state management in protocol parsing components.
The operational impact of this vulnerability extends beyond simple service disruption, as it creates a reliable method for attackers to cause Wireshark to become unresponsive and consume excessive system resources. When an analyst or security professional attempts to analyze network traffic containing maliciously crafted Bazaar protocol packets, the dissector enters an infinite loop that can persist until the system is manually terminated or the process is killed. This renders the network traffic analysis capabilities of Wireshark completely ineffective and can potentially impact security monitoring operations that rely on continuous packet analysis. The vulnerability affects the fundamental operational integrity of the tool and can be exploited in scenarios where network traffic analysis is critical for security incident response.
The fix implemented by the Wireshark development team in epan/dissectors/packet-bzr.c involved enforcing strict forward progress requirements during packet parsing operations. This mitigation ensures that backwards parsing operations cannot occur, thereby preventing the infinite loop condition from manifesting. The solution addresses the core issue by implementing proper loop termination conditions and input validation checks that prevent malformed packets from causing the dissector to enter an unrecoverable state. This approach aligns with the ATT&CK framework's defensive techniques for preventing execution of malicious code through input validation and proper state management. The patch demonstrates the importance of robust error handling and input validation in network protocol analysis tools, which must be able to process potentially malicious network traffic without compromising system stability. The vulnerability serves as a reminder of the critical importance of defensive programming practices in security tools that process untrusted network data, particularly those designed to analyze potentially malicious traffic in security operations centers and forensic investigations.