CVE-2018-9257 in Wireshark
Summary
by MITRE
In Wireshark 2.4.0 to 2.4.5, the CQL dissector could go into an infinite loop. This was addressed in epan/dissectors/packet-cql.c by checking for a nonzero number of columns.
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Analysis
by VulDB Data Team • 02/26/2023
The vulnerability identified as CVE-2018-9257 represents a critical denial of service flaw within Wireshark's CQL dissector component. This issue affected versions 2.4.0 through 2.4.5 of the popular network protocol analyzer, where the dissector responsible for parsing Cassandra Query Language traffic contained a fundamental flaw that could be exploited to cause system instability. The CQL dissector is designed to interpret and display Cassandra database query language packets, enabling network analysts and security professionals to examine database communication patterns within captured network traffic. When processing malformed or specially crafted CQL packets, the dissector would enter an infinite loop, consuming excessive system resources and potentially causing the entire Wireshark application to become unresponsive or crash entirely.
The technical root cause of this vulnerability stems from inadequate input validation within the packet parsing logic. Specifically, the dissector in epan/dissectors/packet-cql.c failed to properly validate the number of columns present in CQL packets before proceeding with the parsing process. This oversight created a condition where malformed packets containing zero or invalid column counts could cause the dissector to enter an infinite loop during packet processing. The flaw is particularly concerning because it operates at the protocol dissector level, meaning any user who opens a maliciously crafted capture file containing such packets will trigger the vulnerable code path without requiring any special privileges or authentication. The infinite loop occurs when the dissector attempts to iterate through columns without proper bounds checking, leading to uncontrolled resource consumption and application instability.
The operational impact of this vulnerability extends beyond simple application crashes, as it represents a potential vector for denial of service attacks against network analysis infrastructure. Network security teams who rely on Wireshark for traffic analysis and incident response could find their monitoring tools rendered unusable by a single malicious packet or capture file. This vulnerability particularly affects organizations that analyze database traffic or use Wireshark in security operations centers where continuous monitoring is critical. The flaw also demonstrates the importance of robust input validation in network protocol analysis tools, as the dissector's failure to properly validate packet structure could be exploited in environments where users might encounter untrusted network traffic. Additionally, this vulnerability impacts automated analysis systems that process large volumes of network data, potentially causing cascading failures in network monitoring pipelines.
The remediation implemented in the fixed versions addressed the core issue by introducing a simple yet effective validation check to ensure that the dissector only processes packets with a nonzero number of columns. This fix aligns with established security practices for preventing infinite loops in protocol parsing code and follows the principle of defensive programming. The solution specifically targets the CWE-835 vulnerability category, which deals with loops that do not terminate properly, and represents a classic example of how insufficient input validation can lead to denial of service conditions. Organizations should prioritize updating to Wireshark versions that include this fix, as the vulnerability remains exploitable in affected releases. The mitigation strategy also emphasizes the importance of regular software updates and maintaining current versions of network analysis tools to protect against known vulnerabilities, particularly those that can be triggered through passive packet analysis without requiring active user interaction or elevated privileges.