nextcloud desktop CVE-2021-37617 is a vulnerability in Nextcloud Desktop
Published on August 18, 2021

Untrusted Search Path in Nextcloud Desktop Client
The Nextcloud Desktop Client is a tool to synchronize files from Nextcloud Server with a computer. The Nextcloud Desktop Client invokes its uninstaller script when being installed to make sure there are no remnants of previous installations. In versions 3.0.3 through 3.2.4, the Client searches the `Uninstall.exe` file in a folder that can be written by regular users. This could lead to a case where a malicious user creates a malicious `Uninstall.exe`, which would be executed with administrative privileges on the Nextcloud Desktop Client installation. This issue is fixed in Nextcloud Desktop Client version 3.3.0. As a workaround, do not allow untrusted users to create content in the `C:\` system folder and verify that there is no malicious `C:\Uninstall.exe` file on the system.

NVD

Vulnerability Analysis

CVE-2021-37617 can be exploited with local system access, requires user interaction and a small amount of user privileges. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to be very high.

Attack Vector:
LOCAL
Attack Complexity:
LOW
Privileges Required:
LOW
User Interaction:
REQUIRED
Scope:
UNCHANGED
Confidentiality Impact:
HIGH
Integrity Impact:
HIGH
Availability Impact:
HIGH

Weakness Type

What is an Untrusted Path Vulnerability?

The application searches for critical resources using an externally-supplied search path that can point to resources that are not under the application's direct control.

CVE-2021-37617 has been classified to as an Untrusted Path vulnerability or weakness.


Products Associated with CVE-2021-37617

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Affected Versions

nextcloud security-advisories Version >= 3.0.3 , <= 3.2.4 is affected by CVE-2021-37617

Exploit Probability

EPSS
0.30%
Percentile
52.88%

EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.