CVE-2020-3203 in IOS XE
Summary
by MITRE
A vulnerability in the locally significant certificate (LSC) provisioning feature of Cisco Catalyst 9800 Series Wireless Controllers that are running Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a memory leak that could lead to a denial of service (DoS) condition. The vulnerability is due to incorrect processing of certain public key infrastructure (PKI) packets. An attacker could exploit this vulnerability by sending crafted Secure Sockets Layer (SSL) packets to an affected device. A successful exploit could cause an affected device to continuously consume memory, which could result in a memory allocation failure that leads to a crash and causes a DoS condition.
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Analysis
by VulDB Data Team • 10/21/2020
The vulnerability identified as CVE-2020-3203 resides within the locally significant certificate provisioning functionality of Cisco Catalyst 9800 Series Wireless Controllers operating on Cisco IOS XE Software. This weakness represents a critical security flaw that enables unauthenticated remote attackers to initiate denial of service conditions through carefully crafted malicious input. The affected devices operate within enterprise wireless networking environments where uninterrupted service availability is paramount for business operations and network connectivity.
The technical root cause of this vulnerability stems from improper handling of public key infrastructure packets within the SSL processing pipeline of the wireless controller software. Specifically, the system fails to adequately validate or process certain SSL packets that contain PKI elements, leading to memory allocation inconsistencies. This flaw manifests when the controller receives specially constructed SSL packets that exploit gaps in the certificate processing logic, causing the device to continuously consume memory resources without proper cleanup or allocation management. The improper packet handling creates a memory leak condition that progressively depletes available system memory.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise entire wireless network infrastructures. When exploited successfully, the memory leak causes the affected controller to experience continuous memory consumption until system resources are exhausted, resulting in complete device crash and subsequent denial of service. This condition affects wireless network availability for all connected clients and can disrupt critical business operations that depend on wireless connectivity. Network administrators may experience prolonged downtime while attempting to restore service, particularly in large enterprise environments where multiple controllers manage extensive wireless deployments.
This vulnerability aligns with CWE-122, which describes improper restriction of operations within the bounds of a memory buffer, and maps to ATT&CK technique T1499.002, which covers network denial of service attacks. The attack vector requires only remote access without authentication credentials, making it particularly dangerous as it can be exploited by attackers who are not physically present or authorized to access the network infrastructure. Organizations implementing Cisco Catalyst 9800 controllers should prioritize immediate remediation through software updates and patches provided by Cisco, while also implementing network segmentation and monitoring to detect potential exploitation attempts. The memory leak behavior described in this vulnerability demonstrates the importance of robust input validation and proper resource management in network infrastructure devices to prevent exploitation scenarios that could lead to widespread service disruption.