CVE-2020-8225 in Desktop Client
Summary
by MITRE
A cleartext storage of sensitive information in Nextcloud Desktop Client 2.6.4 gave away information about used proxies and their authentication credentials.
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Analysis
by VulDB Data Team • 09/19/2020
The vulnerability identified as CVE-2020-8225 represents a critical security flaw in the Nextcloud Desktop Client version 2.6.4 where sensitive proxy authentication credentials were being stored in cleartext format within the application's configuration files. This issue directly violates fundamental security principles by exposing confidential information that should remain protected. The vulnerability stems from the client's improper handling of proxy settings, specifically how it persists authentication details for network proxy servers that the application uses to connect to the internet. When users configure proxy settings for their Nextcloud client, the software stores these credentials in an unencrypted format, making them immediately accessible to any entity with read access to the configuration files. This flaw creates a significant risk for organizations that rely on proxy infrastructure for network monitoring, access control, and security enforcement, as the stored credentials could be exploited by attackers with local system access or those who gain unauthorized access to the client's configuration directories.
The technical implementation of this vulnerability aligns with CWE-312, which specifically addresses the cleartext storage of sensitive information, and represents a clear violation of the principle of least privilege in information security. The Nextcloud Desktop Client stores proxy authentication credentials in plain text within its configuration database, typically located in the user's home directory or application data folders. This design flaw allows any process running with the same user privileges to read these credentials without additional authentication mechanisms. The vulnerability's impact extends beyond simple credential exposure as it provides attackers with direct access to corporate proxy infrastructure, potentially enabling them to bypass network security controls, monitor network traffic, or use the compromised credentials to access additional systems within the network perimeter. From an operational standpoint, this vulnerability creates a persistent threat vector that remains active until the user manually removes the stored credentials or updates to a patched version of the client software.
The operational implications of CVE-2020-8225 are particularly severe in enterprise environments where proxy servers are commonly used for network security enforcement, traffic filtering, and compliance monitoring. Attackers who gain access to a compromised user's system can immediately leverage the stored proxy credentials to establish persistent network access through the organization's proxy infrastructure, effectively bypassing many network security controls that rely on proxy authentication for access enforcement. The vulnerability also aligns with ATT&CK technique T1555.003, which covers credentials from password stores, as the cleartext storage effectively exposes credentials that should remain protected within secure credential management systems. Organizations using Nextcloud Desktop Client in environments with strict security policies face significant compliance risks, as this vulnerability could violate data protection regulations and internal security policies that mandate protection of authentication credentials. The impact is further exacerbated by the fact that these credentials are typically not rotated frequently, creating long-term exposure windows for attackers who discover the stored information. Security professionals should consider implementing monitoring solutions that can detect unauthorized access to configuration files and credential storage locations, while also ensuring that users are educated about the risks of storing proxy credentials in cleartext format.
The recommended mitigations for this vulnerability include immediate patching of the Nextcloud Desktop Client to version 2.6.5 or later, which addresses the cleartext storage issue through proper encryption of stored credentials. Organizations should also implement configuration management practices that prevent the storage of proxy authentication credentials in the first place, or ensure that any stored credentials are properly encrypted using industry-standard encryption algorithms. System administrators should conduct regular audits of client configuration files to identify and remove any stored proxy credentials, while also implementing access controls that limit read permissions to sensitive configuration files. Additionally, organizations should consider deploying network monitoring solutions that can detect unusual proxy authentication patterns or unauthorized access attempts that might indicate credential compromise. The vulnerability serves as a reminder of the critical importance of secure credential handling in client applications and the necessity of implementing proper encryption and access control mechanisms for sensitive information storage.