CVE-2017-6472 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 RTMPT dissector infinite loop, triggered by packet injection or a malformed capture file. This was addressed in epan/dissectors/packet-rtmpt.c by properly incrementing a certain sequence value.
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Analysis
by VulDB Data Team • 10/15/2019
The vulnerability identified as CVE-2017-6472 represents a critical denial-of-service flaw within Wireshark's RTMPT dissector functionality. This issue affects versions 2.2.0 through 2.2.4 and 2.0.0 through 2.0.10, where the network protocol dissector for RTMPT (Real-Time Messaging Protocol over HTTP) contains a logic error that can cause the application to enter an infinite loop during packet processing. The vulnerability manifests when Wireshark encounters either injected packets or malformed capture files that trigger the problematic dissector code, potentially leading to complete application hang or crash.
The technical root cause of this vulnerability resides in the packet-rtmpt.c file within Wireshark's epan/dissectors directory, where a sequence value is not properly incremented during the dissector's processing loop. This failure in sequence management creates a condition where the dissector's internal state does not advance correctly, causing it to repeatedly process the same packet data without termination. The flaw operates under CWE-835, which specifically addresses the issue of loop termination conditions that can lead to infinite loops in software implementations. This particular implementation error demonstrates how a simple missing increment operation can create a catastrophic failure in network analysis tools that must process potentially malicious or malformed network traffic.
The operational impact of this vulnerability extends beyond simple application instability, as it creates a potential vector for denial-of-service attacks against network analysts and security professionals who rely on Wireshark for network traffic analysis. Attackers could exploit this vulnerability by crafting specially formatted RTMPT packets or capture files that, when opened in Wireshark, would cause the application to consume excessive CPU resources or crash entirely. This makes the vulnerability particularly dangerous in environments where network monitoring tools are critical for security operations, as it could be used to disrupt network analysis activities or potentially mask other malicious network traffic by causing the monitoring tool to become unresponsive. The vulnerability aligns with ATT&CK technique T1499.001, which covers network denial-of-service attacks targeting network infrastructure and monitoring tools.
The remediation for this vulnerability involved implementing proper sequence value incrementation within the RTMPT dissector code, ensuring that the internal processing loop would terminate correctly after processing each packet. This fix addresses the core logic error that caused the infinite loop condition and restores normal Wireshark functionality when processing RTMPT protocol data. The fix demonstrates the importance of proper state management in protocol dissectors, where each packet must be processed exactly once to prevent such infinite loop scenarios. Organizations using affected Wireshark versions should immediately upgrade to patched releases to eliminate this vulnerability and maintain the integrity of their network monitoring capabilities.