CVE-2021-21600 in NetWorker
Summary
by MITRE • 08/11/2021
Dell EMC NetWorker, 19.4 or older, contain an uncontrolled resource consumption flaw in its API service. An authorized API user could potentially exploit this vulnerability via the web and desktop user interfaces, leading to denial of service in the manageability path.
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Analysis
by VulDB Data Team • 08/15/2021
The vulnerability identified as CVE-2021-21600 affects Dell EMC NetWorker versions 19.4 and earlier, representing a critical uncontrolled resource consumption flaw within the system's API service component. This weakness specifically targets the manageability path of the software, creating a potential avenue for denial of service attacks that could severely impact system availability and operational continuity. The vulnerability exists in the API service implementation, which processes requests from both web and desktop user interfaces, making it accessible to authorized users who may exploit the flaw for malicious purposes.
The technical nature of this vulnerability stems from inadequate resource management within the API service, where the system fails to properly constrain or limit resource consumption during request processing. This allows an authenticated user to submit crafted requests that consume excessive system resources such as memory, CPU cycles, or connection handles, ultimately leading to service degradation or complete system unavailability. The flaw is particularly concerning because it operates within the manageability path, meaning legitimate users with proper authentication credentials could leverage this weakness without requiring additional privileges or specialized attack vectors. The vulnerability manifests through the web and desktop user interfaces, which means attackers can exploit it using standard user-facing components rather than requiring direct system access or specialized tools.
From an operational impact perspective, this vulnerability creates significant risk for organizations relying on Dell EMC NetWorker for backup and recovery operations. The denial of service condition could disrupt critical data protection workflows, potentially leading to extended downtime for backup services and compromising the organization's ability to recover data during emergencies. The attack surface is broadened by the fact that both web and desktop interfaces provide access points, meaning the vulnerability could be exploited through multiple user interaction methods. Organizations may experience cascading effects where the service disruption impacts other dependent systems or processes that rely on the NetWorker environment for their operations.
Security professionals should note that this vulnerability aligns with CWE-400, which addresses uncontrolled resource consumption, and represents a classic example of resource exhaustion attacks that can be classified under the ATT&CK technique T1499.004 for network denial of service. The risk is elevated in environments where the API service is exposed to external networks or where users have broad access permissions, as unauthorized exploitation could lead to extended service interruptions. Organizations should prioritize immediate remediation through official Dell EMC patches and updates, while implementing monitoring solutions to detect unusual resource consumption patterns that may indicate exploitation attempts. Additionally, network segmentation and access controls should be reviewed to limit exposure of the vulnerable API service components, particularly in environments where the web and desktop interfaces are publicly accessible or where user privilege levels are not properly restricted.