CVE-2022-39211 in Server
Summary
by MITRE • 09/17/2022
Nextcloud server is an open source personal cloud platform. In affected versions it was found that locally running webservices can be found and requested erroneously. It is recommended that the Nextcloud Server is upgraded to 23.0.8 or 24.0.4. It is recommended that the Nextcloud Enterprise Server is upgraded to 22.2.10.4, 23.0.8 or 24.0.4. There are no known workarounds for this issue.
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Analysis
by VulDB Data Team • 10/20/2022
The vulnerability identified as CVE-2022-39211 affects Nextcloud server versions prior to the specified patches, representing a significant security flaw in the platform's web service handling mechanisms. This issue stems from improper validation of locally running web services that can be discovered and accessed through unauthorized requests, creating a potential attack vector for malicious actors who may exploit this misconfiguration to gain unauthorized access to internal services. The vulnerability specifically impacts the server's ability to properly isolate and secure locally running web services, allowing them to be accessed through external requests that should be restricted to local network boundaries.
The technical implementation of this vulnerability involves a failure in the service discovery and access control mechanisms within Nextcloud's web server architecture. When web services are running locally on the Nextcloud server, the platform fails to properly enforce access restrictions that should prevent external entities from making requests to these services. This misconfiguration creates an information disclosure risk where attackers can potentially enumerate and interact with services that should remain isolated within the local network environment. The flaw operates at the network layer where service boundaries are not properly enforced, allowing for unauthorized access patterns that violate basic network security principles.
From an operational impact perspective, this vulnerability represents a critical risk to organizations relying on Nextcloud for personal cloud storage and collaboration services. The potential for unauthorized access to locally running web services could enable attackers to escalate privileges, access sensitive data, or even gain control over the underlying system. The vulnerability's impact extends beyond simple data exposure, as it may allow for lateral movement within the network infrastructure where Nextcloud servers are deployed. Organizations using Nextcloud Enterprise Server face the same risks, with the additional complexity of enterprise-scale deployments potentially amplifying the impact of such unauthorized access points. This issue directly violates security best practices outlined in the OWASP Top Ten, specifically addressing the risk of insufficient logging and monitoring, as well as the lack of proper access control mechanisms.
The recommended remediation strategy involves upgrading to the specified patched versions of Nextcloud Server and Nextcloud Enterprise Server. Version 23.0.8 and 24.0.4 for standard Nextcloud Server, along with version 22.2.10.4, 23.0.8, or 24.0.4 for Enterprise Server, contain the necessary fixes to address the service discovery and access control issues. These patches implement proper boundary enforcement for locally running web services and ensure that external requests cannot inadvertently access internal service endpoints. Security teams should prioritize this upgrade as a critical remediation step, particularly in environments where Nextcloud servers are exposed to untrusted networks or where sensitive data is stored. The lack of known workarounds for this vulnerability emphasizes the importance of immediate patch deployment to prevent potential exploitation.
This vulnerability aligns with CWE-284 (Improper Access Control) and CWE-200 (Information Exposure) categories, reflecting fundamental security misconfigurations in access control enforcement. The ATT&CK framework categorizes this as a privilege escalation or lateral movement technique where attackers exploit service misconfigurations to gain unauthorized access to system resources. Organizations should implement network segmentation and monitoring controls to detect unusual service access patterns, while also ensuring that all Nextcloud deployments are regularly updated to maintain security posture against similar vulnerabilities. The vulnerability demonstrates the importance of proper service isolation and access control implementation in cloud-based platforms, highlighting the need for comprehensive security testing of service discovery mechanisms in open source platforms.