CVE-2017-6780 in Connected Grid Network Management System
Summary
by MITRE
A vulnerability in the TCP throttling process for Cisco IoT Field Network Director (IoT-FND) could allow an unauthenticated, remote attacker to cause the system to consume additional memory, eventually forcing the device to restart, aka Memory Exhaustion. The vulnerability is due to insufficient rate-limiting protection. An attacker could exploit this vulnerability by sending a high rate of TCP packets to a specific group of open listening ports on a targeted device. An exploit could allow the attacker to cause the system to consume additional memory. If enough available memory is consumed, the system will restart, creating a temporary denial of service (DoS) condition. The DoS condition will end after the device has finished the restart process. This vulnerability affects the following Cisco products: Connected Grid Network Management System, if running a software release prior to IoT-FND Release 4.0; IoT Field Network Director, if running a software release prior to IoT-FND Release 4.0. Cisco Bug IDs: CSCvc77164.
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Analysis
by VulDB Data Team • 01/11/2021
The vulnerability identified as CVE-2017-6780 represents a critical memory exhaustion flaw within Cisco's IoT Field Network Director (IoT-FND) system, specifically affecting devices running software releases prior to IoT-FND Release 4.0. This weakness resides in the TCP throttling mechanism that governs how the system handles incoming network connections, creating a pathway for remote attackers to exploit the device's memory management capabilities. The vulnerability operates through a sophisticated process where an unauthenticated attacker can manipulate the system's resource allocation by flooding targeted listening ports with excessive TCP packets, ultimately leading to system instability and temporary service disruption.
The technical implementation of this vulnerability stems from inadequate rate-limiting controls within the TCP processing pipeline of the IoT-FND system. When the device receives a high volume of TCP packets directed at specific open listening ports, the insufficient rate-limiting mechanisms fail to properly throttle the incoming traffic, allowing the system to continuously allocate memory resources without proper bounds. This design flaw creates a memory consumption spiral where each incoming packet triggers additional memory allocation, eventually exhausting the available system memory pool. The vulnerability aligns with CWE-400, which categorizes "Uncontrolled Resource Consumption" as a fundamental weakness in software systems, where resource allocation lacks proper limits or monitoring controls. The system's inability to properly manage TCP connection requests demonstrates a critical oversight in network protocol handling that directly impacts system availability.
The operational impact of this vulnerability extends beyond simple service disruption to create a comprehensive denial of service condition that affects critical infrastructure management systems. When the memory exhaustion occurs, the affected device undergoes an automatic restart process, creating temporary service interruption that can severely impact grid network management operations. The restart process typically resolves the immediate condition, but the frequency and duration of such events can significantly degrade network reliability and operational efficiency. This vulnerability particularly affects the Connected Grid Network Management System and IoT Field Network Director deployments where the software version predates IoT-FND Release 4.0, making these installations particularly susceptible to exploitation. The DoS condition created by this vulnerability directly aligns with ATT&CK technique T1499.004, which covers "Endpoint Denial of Service" through resource exhaustion attacks.
Mitigation strategies for CVE-2017-6780 should prioritize immediate software updates to IoT-FND Release 4.0 or later versions where the rate-limiting protections have been implemented. Network administrators should also implement additional protective measures including ingress filtering, access control lists, and rate-limiting at network boundaries to prevent the exploitation of this vulnerability. The implementation of TCP SYN cookies and connection tracking mechanisms can provide additional layers of protection against this type of resource exhaustion attack. Organizations should also consider deploying network monitoring solutions that can detect unusual traffic patterns and automatically alert administrators to potential exploitation attempts. Security teams should conduct regular vulnerability assessments to ensure all IoT-FND installations are properly updated and that network configurations follow best practices for preventing unauthorized access to listening ports. The vulnerability highlights the critical importance of proper resource management in network infrastructure systems and the necessity of implementing robust rate-limiting controls to prevent exploitation of similar weaknesses in other network protocols and services.