CVE-2017-7704 in Wireshark
Summary
by MITRE
In Wireshark 2.2.0 to 2.2.5, the DOF dissector could go into an infinite loop, triggered by packet injection or a malformed capture file. This was addressed in epan/dissectors/packet-dof.c by using a different integer data type and adjusting a return value.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 11/29/2022
The vulnerability identified as CVE-2017-7704 represents a critical denial of service flaw within Wireshark's packet analysis capabilities, specifically affecting versions 2.2.0 through 2.2.5. This issue manifests in the DOF (Data Object Format) dissector component which is responsible for parsing and interpreting specific network protocols. The flaw occurs when the dissector encounters malformed packet data or is subjected to packet injection attacks, creating a condition where the processing routine becomes trapped in an infinite loop. Such behavior fundamentally compromises the stability and usability of the network analysis tool, as the application becomes unresponsive and requires manual intervention to restore functionality. The vulnerability directly impacts the core operational integrity of Wireshark, which serves as a fundamental tool for network administrators, security analysts, and forensic investigators who rely on its consistent performance for network troubleshooting and security monitoring.
The technical implementation of this vulnerability stems from a specific coding error within the epan/dissectors/packet-dof.c file where the dissector utilizes an inappropriate integer data type that fails to properly handle certain boundary conditions during packet parsing operations. When malformed data triggers the processing logic, the integer overflow or underflow conditions cause the loop control variables to never reach their termination criteria, resulting in continuous execution without progress. This type of flaw aligns with CWE-128, which addresses "Unsigned to Signed Conversion Error" and represents a classic example of improper integer handling that can lead to denial of service conditions. The vulnerability's exploitation requires either the injection of specially crafted packets into a live network capture or the manipulation of existing capture files to contain malformed DOF data structures that trigger the problematic code path. The return value handling was also identified as a contributing factor, where the function's exit conditions were not properly configured to terminate execution under abnormal circumstances, creating a scenario where the dissector routine remains perpetually active.
The operational impact of CVE-2017-7704 extends beyond simple application instability to represent a significant security risk for network monitoring environments where Wireshark serves as a critical component. When exploited, this vulnerability can render network analysis tools unusable during critical security incidents or network troubleshooting sessions, potentially delaying incident response times and compromising security operations. The infinite loop condition means that even a single malformed packet can cause the entire application to become unresponsive, affecting not just the analysis of that particular packet but potentially the entire network traffic analysis session. This vulnerability particularly impacts organizations that rely on automated network monitoring systems or continuous capture scenarios where the application must maintain stable operation for extended periods. The flaw also represents a potential vector for attackers to disrupt network security operations, as they could potentially cause network analysts to lose access to critical monitoring capabilities during security incidents, creating a cascading effect that undermines broader security infrastructure reliability.
The remediation for this vulnerability involved a targeted code modification within the packet-dof.c file that addressed both the integer data type issue and the return value handling. The fix implemented a more robust integer data type selection that properly handles boundary conditions and ensures that loop termination criteria are always achievable regardless of input data. Additionally, the return value handling was adjusted to ensure proper function exit conditions are maintained even when processing malformed data. This fix aligns with ATT&CK technique T1499.004, which covers "Domain Generation Algorithms" and similar denial of service attacks that exploit software implementation flaws. Organizations should immediately upgrade to Wireshark versions 2.2.6 or later where this vulnerability has been addressed through proper input validation and robust error handling mechanisms. System administrators should also implement monitoring for unusual application behavior patterns that might indicate exploitation attempts and ensure that network capture files are validated before processing in production environments to prevent accidental triggering of such vulnerabilities. The fix demonstrates the importance of proper integer handling in network protocol analysis tools and serves as a reminder of how seemingly minor implementation details can create significant stability and security implications in critical infrastructure software.