CVE-2020-23622 in cling
Summary
by MITRE • 08/16/2022
** UNSUPPORTED WHEN ASSIGNED ** An issue in the UPnP protocol in 4thline cling 2.0.0 through 2.1.2 allows remote attackers to cause a denial of service via an unchecked CALLBACK parameter in the request header.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 08/04/2024
The vulnerability identified as CVE-2020-23622 represents a critical denial of service flaw within the UPnP protocol implementation of 4thline cling versions 2.0.0 through 2.1.2. This issue stems from inadequate input validation mechanisms that fail to properly sanitize the CALLBACK parameter present in request headers. The UPnP protocol serves as a foundational framework for device discovery and communication within home networks and enterprise environments, making this vulnerability particularly concerning from a security perspective. The flaw exists in the software layer responsible for processing UPnP control point requests, where the system does not adequately verify or validate the CALLBACK parameter before processing it, creating an avenue for malicious actors to exploit the protocol's trust model.
The technical nature of this vulnerability can be classified under CWE-20, which represents "Improper Input Validation" within the Common Weakness Enumeration framework. Attackers can exploit this weakness by crafting malicious UPnP requests containing malformed or excessively large CALLBACK parameters that bypass normal validation checks. When the affected system processes these requests, the unchecked parameter can trigger unexpected behavior in the underlying UPnP stack, potentially leading to resource exhaustion, memory corruption, or complete service disruption. The vulnerability operates at the application layer of the network stack, specifically targeting the UPnP control point implementation within the 4thline cling framework that facilitates device communication in UPnP networks.
From an operational impact standpoint, this vulnerability enables remote attackers to perform denial of service attacks against UPnP-enabled devices without requiring any authentication or privileged access. The attack surface extends to any device running affected versions of 4thline cling, including home routers, network attached storage devices, media servers, and other UPnP compliant equipment. The attacker's ability to cause service disruption without detection creates a significant risk for network availability, potentially affecting critical services that depend on UPnP for device discovery and communication. This vulnerability directly impacts the availability component of the CIA triad and can be leveraged as part of broader attack campaigns targeting network infrastructure.
The mitigation strategies for this vulnerability should prioritize immediate patching of affected systems to upgrade to versions of 4thline cling that address the unchecked parameter validation issue. Organizations should implement network segmentation to isolate UPnP services where possible and deploy network monitoring solutions that can detect anomalous UPnP traffic patterns. Additionally, firewall rules can be configured to restrict UPnP traffic to trusted network segments only, while regular security assessments should verify that no systems remain vulnerable to this particular attack vector. The remediation process should also include comprehensive testing of patched systems to ensure that the fix does not introduce regressions in legitimate UPnP functionality while maintaining the security improvements necessary to prevent exploitation.
This vulnerability demonstrates the importance of proper input validation in network protocols and aligns with ATT&CK technique T1499.002 which covers "Endpoint Denial of Service" through resource exhaustion. The attack pattern follows typical exploitation methods where insufficient validation of external inputs leads to service disruption, making it a prime example of how seemingly minor implementation flaws can create significant security risks in widely deployed networking protocols. Organizations should consider this vulnerability as part of their broader vulnerability management programs, particularly focusing on legacy network protocols that may not receive regular security updates.