CVE-2022-20692 in IOS XE
Summary
by MITRE • 04/15/2022
A vulnerability in the NETCONF over SSH feature of Cisco IOS XE Software could allow a low-privileged, authenticated, remote attacker to cause a denial of service condition (DoS) on an affected device. This vulnerability is due to insufficient resource management. An attacker could exploit this vulnerability by initiating a large number of NETCONF over SSH connections. A successful exploit could allow the attacker to exhaust resources, causing the device to reload and resulting in a DoS condition on an affected device.
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Analysis
by VulDB Data Team • 04/20/2022
The vulnerability identified as CVE-2022-20692 represents a critical resource management flaw within Cisco IOS XE Software's NETCONF over SSH implementation. This issue affects network devices that utilize the Network Configuration Protocol (NETCONF) for remote configuration management over Secure Shell connections. The vulnerability stems from inadequate handling of connection resources, creating a pathway for malicious actors to exploit the system's limited capacity for managing concurrent sessions. The flaw specifically manifests when the software fails to properly regulate and limit the number of active NETCONF over SSH connections that can be established simultaneously. This weakness allows an attacker to consume available system resources through excessive connection attempts, ultimately leading to system instability and operational disruption.
The technical exploitation of this vulnerability requires an attacker to possess valid authentication credentials and network access to the affected device. The attack vector involves initiating numerous concurrent NETCONF over SSH connections, which overwhelms the device's resource allocation mechanisms. The insufficient resource management manifests as the system's inability to properly terminate or limit connection sessions, causing memory and processing resources to become exhausted. When resource exhaustion occurs, the device's operational integrity is compromised, leading to automatic system reloads and subsequent denial of service conditions. This type of vulnerability falls under CWE-400, which classifies resource exhaustion issues in software systems. The vulnerability demonstrates a classic example of a resource leak or resource management failure that can be exploited through amplified connection attempts.
The operational impact of CVE-2022-20692 extends beyond simple service disruption to potentially compromise network infrastructure stability and availability. Organizations relying on Cisco IOS XE devices for network configuration management face significant risks when this vulnerability is exploited, as it can render critical network components inaccessible during attack periods. The DoS condition affects not only the specific device but can also impact broader network operations, particularly in environments where multiple devices depend on centralized configuration management. Attackers can leverage this vulnerability to cause cascading failures in network infrastructure, especially in scenarios where network administrators rely heavily on automated configuration deployment through NETCONF interfaces. The vulnerability's low privilege requirements and remote exploitability make it particularly dangerous in production environments where network devices are accessible over public networks.
Mitigation strategies for CVE-2022-20692 should focus on implementing robust connection rate limiting and resource management controls within the affected Cisco IOS XE devices. Network administrators should configure maximum connection limits for NETCONF over SSH sessions to prevent resource exhaustion attacks from succeeding. The implementation of access control lists and firewall rules can help restrict access to NETCONF interfaces to trusted IP addresses only, reducing the attack surface. Additionally, monitoring systems should be deployed to detect unusual connection patterns and alert administrators to potential exploitation attempts. Cisco has released software updates and patches addressing this vulnerability, which should be applied immediately to affected systems. The remediation process should also include implementing network segmentation strategies that isolate critical network infrastructure from general network access, following the principle of least privilege as outlined in the NIST Cybersecurity Framework. Organizations should also consider implementing intrusion detection systems that can identify and respond to abnormal connection behaviors that may indicate exploitation attempts.