CVE-2017-6470 in Wireshark
Summary
by MITRE
In Wireshark 2.2.0 to 2.2.4 and 2.0.0 to 2.0.10, there is an IAX2 infinite loop, triggered by packet injection or a malformed capture file. This was addressed in epan/dissectors/packet-iax2.c by constraining packet lateness.
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Analysis
by VulDB Data Team • 10/15/2019
The vulnerability identified as CVE-2017-6470 represents a critical denial of service flaw affecting Wireshark versions ranging from 2.2.0 through 2.2.4 and 2.0.0 through 2.0.10. This issue manifests as an infinite loop within the IAX2 protocol dissector, specifically in the epan/dissectors/packet-iax2.c file. The vulnerability operates through a combination of packet injection attacks and malformed capture file manipulation, creating a scenario where the network protocol analyzer becomes trapped in an endless processing cycle. The root cause stems from inadequate validation of packet timing parameters within the IAX2 dissector implementation, which fails to properly handle cases where packet lateness exceeds predetermined thresholds.
The technical exploitation of this vulnerability occurs when an attacker crafts malicious IAX2 packets or provides malformed capture files containing improperly timed packets. The dissector's logic does not adequately constrain packet lateness measurements, leading to a condition where the processing loop continuously evaluates and re-evaluates packet timing data without reaching a termination point. This behavior directly violates the fundamental principle of bounded execution time for network protocol analysis tools, as defined by CWE-835 which addresses infinite loops and related issues in software implementations. The flaw creates a predictable denial of service condition that can be triggered remotely through packet injection or locally through malicious capture file manipulation.
The operational impact of CVE-2017-6470 extends beyond simple service disruption, as it affects the reliability and availability of network analysis operations that depend on Wireshark for protocol inspection. When exploited, the infinite loop consumes excessive CPU resources and prevents the application from processing additional packets or files, effectively rendering the network monitoring capability useless. This vulnerability particularly impacts security analysts, network administrators, and incident responders who rely on Wireshark for network traffic analysis and troubleshooting. The flaw's characteristics align with ATT&CK technique T1499.001 which describes resource exhaustion attacks, and more specifically targets the availability aspect of the CIA triad by compromising system functionality. Organizations using affected Wireshark versions face potential operational downtime and reduced network visibility during the exploitation period.
Mitigation strategies for CVE-2017-6470 focus on immediate version upgrades to patched releases of Wireshark, which address the issue through enhanced packet lateness constraints in the IAX2 dissector code. The fix implemented in epan/dissectors/packet-iax2.c establishes proper bounds on packet timing validation, preventing the infinite loop condition from occurring. Network administrators should also implement additional defensive measures including capture file validation procedures, network segmentation to limit exposure, and monitoring for unusual CPU utilization patterns that might indicate exploitation attempts. The vulnerability demonstrates the importance of proper input validation and resource management in protocol analysis tools, reinforcing the need for comprehensive testing of dissector implementations against malformed data inputs. Organizations should conduct vulnerability assessments to identify systems running affected Wireshark versions and ensure timely patch deployment to maintain network monitoring capabilities and prevent potential exploitation by malicious actors.