CVE-2020-3372 in SD-WAN vManage
Summary
by MITRE
A vulnerability in the web-based management interface of Cisco SD-WAN vManage Software could allow an authenticated, remote attacker to consume excessive system memory and cause a denial of service (DoS) condition on an affected system. The vulnerability is due to inefficient memory management. An attacker could exploit this vulnerability by sending a large number of crafted HTTP requests to the affected web-based management interface. A successful exploit could allow the attacker to exhaust system memory, which could cause the system to stop processing new connections and could result in a DoS condition.
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Analysis
by VulDB Data Team • 11/04/2020
The vulnerability identified as CVE-2020-3372 resides within the web-based management interface of Cisco SD-WAN vManage Software, representing a critical security flaw that enables authenticated remote attackers to execute denial of service attacks through excessive memory consumption. This vulnerability specifically targets the software's handling of HTTP requests within its management interface, where inefficient memory management practices create exploitable conditions that can severely impact system availability. The affected Cisco SD-WAN vManage Software operates as a central management platform for software-defined wide area networks, making it a critical component in enterprise networking infrastructure where reliability and uptime are paramount for business operations.
The technical flaw manifests through inadequate memory allocation and deallocation mechanisms within the web interface's request processing pipeline. When an authenticated attacker sends a large volume of crafted HTTP requests to the management interface, the system's inefficient memory management causes memory resources to be consumed at an unsustainable rate. This occurs because the software fails to properly implement memory cleanup procedures or request rate limiting mechanisms that would prevent excessive resource consumption. The vulnerability stems from CWE-400, which categorizes unspecified memory errors that can lead to resource exhaustion, and aligns with ATT&CK technique T1499.100 which describes resource exhaustion attacks targeting network infrastructure. The flaw does not require privileged access beyond authentication, making it particularly dangerous as any authenticated user could potentially exploit it.
The operational impact of this vulnerability extends beyond simple service disruption, creating cascading effects that can severely compromise network management capabilities. When system memory is exhausted, the affected vManage software instance becomes unable to process new connections or maintain existing sessions, effectively rendering the network management interface unavailable to legitimate administrators. This creates a situation where network operators cannot monitor or manage their SD-WAN infrastructure, potentially leading to extended outages and operational downtime. The DoS condition can persist until system resources are manually cleared or the device is restarted, with no automated recovery mechanisms to prevent or mitigate the memory exhaustion. Network administrators may find themselves unable to perform critical maintenance tasks, update configurations, or respond to network incidents, fundamentally undermining the reliability and security posture of the managed network infrastructure.
Mitigation strategies for CVE-2020-3372 should focus on both immediate defensive measures and long-term architectural improvements to prevent similar vulnerabilities. Organizations should implement strict rate limiting and connection monitoring on the vManage management interface to detect and prevent abnormal request patterns that could indicate exploitation attempts. Network segmentation and access controls should be enhanced to limit the number of authenticated users with access to the management interface, reducing the attack surface. Cisco has released patches and updates to address this vulnerability, which should be deployed immediately across all affected systems. System administrators should also implement monitoring solutions that track memory utilization and connection counts to provide early warning of potential exploitation attempts. Additionally, implementing network-based intrusion detection systems can help identify and block malicious HTTP request patterns before they can cause significant damage. The vulnerability highlights the importance of proper resource management in web applications and underscores the need for security testing that includes stress and load testing scenarios to identify potential resource exhaustion vulnerabilities.