CVE-2022-20847 in IOS XE
Summary
by MITRE • 09/30/2022
A vulnerability in the DHCP processing functionality of Cisco IOS XE Wireless Controller Software for the Catalyst 9000 Family could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. This vulnerability is due to the improper processing of DHCP messages. An attacker could exploit this vulnerability by sending malicious DHCP messages to an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.
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Analysis
by VulDB Data Team • 10/29/2022
The vulnerability identified as CVE-2022-20847 resides within the DHCP processing mechanisms of Cisco IOS XE Wireless Controller Software deployed on Catalyst 9000 Family devices. This represents a critical weakness in network infrastructure management that could be exploited by remote attackers without requiring authentication credentials. The flaw specifically manifests in the manner in which the affected software handles incoming DHCP messages, creating a potential pathway for malicious actors to disrupt network operations. The Cisco IOS XE Wireless Controller Software serves as a fundamental component in enterprise wireless network deployments, making this vulnerability particularly concerning for organizations relying on Catalyst 9000 infrastructure for their wireless connectivity needs. The vulnerability impacts the core functionality of wireless network controllers, potentially affecting thousands of devices across enterprise networks that utilize Cisco's wireless solutions.
The technical root cause of this vulnerability stems from improper validation and handling of DHCP messages within the wireless controller software implementation. When the system receives DHCP packets, it fails to properly process or sanitize the incoming data structures, leading to potential buffer overflows or memory corruption conditions. This flaw allows attackers to craft specifically designed DHCP messages that trigger unexpected behavior in the processing pipeline. The improper message handling creates a condition where the software cannot gracefully manage malformed or maliciously constructed DHCP packets, resulting in system instability. According to CWE classification, this vulnerability aligns with CWE-129 Input Validation and OWASP Top Ten category A03: Injection, as it involves improper handling of network protocol data that can lead to system disruption. The software's DHCP processing module lacks adequate input sanitization and boundary checking mechanisms, making it susceptible to exploitation through carefully constructed network traffic.
The operational impact of successfully exploiting CVE-2022-20847 can be severe for affected organizations, potentially causing complete service disruption across wireless network infrastructure. When an attacker successfully triggers the vulnerability, the affected wireless controller device undergoes an automatic reload process, effectively taking the wireless network offline for the duration of the restart cycle. This denial of service condition can result in significant business disruption, particularly in environments where wireless connectivity is critical for operations. The impact extends beyond simple connectivity loss as the reload process may cause temporary loss of wireless management capabilities, affecting network monitoring, configuration changes, and user authentication processes. Organizations may experience cascading effects where dependent systems lose wireless connectivity, potentially impacting productivity, customer service, and operational continuity. The vulnerability's remote exploitability means that attackers do not need physical access to the network equipment, making it particularly dangerous for organizations with exposed wireless infrastructure.
Mitigation strategies for CVE-2022-20847 should focus on immediate defensive measures and long-term architectural improvements. Network administrators should prioritize applying the official Cisco security patches and updates released to address this vulnerability, which typically include enhanced input validation for DHCP message processing. Organizations should implement network segmentation and access controls to limit exposure of wireless controllers to untrusted networks, utilizing firewall rules and access control lists to restrict DHCP traffic to authorized sources only. The implementation of DHCP snooping and dynamic ARP inspection can provide additional layers of protection by validating DHCP messages and preventing malformed packets from reaching the vulnerable components. From an ATT&CK framework perspective, this vulnerability maps to T1499.004 Network Denial of Service and T1071.004 Application Layer Protocol, as it exploits network protocol implementations to cause service disruption. Organizations should also consider implementing network monitoring solutions that can detect anomalous DHCP traffic patterns and alert administrators to potential exploitation attempts. Regular vulnerability assessments and network scanning should be conducted to identify and remediate similar issues across the entire network infrastructure, ensuring comprehensive protection against similar attack vectors.