Home/CVE/The Nextcloud Desktop Client is a tool to synchronize files from Nextcloud Server with a computer. The Nextcloud Desktop
CVE

CVE-2021-37617

The Nextcloud Desktop Client is a tool to synchronize files from Nextcloud Server with a computer. The Nextcloud Desktop

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.

HIGH · CVSS 7.3 EPSS 0.00394
Schedule remediation
  • CVSS base score ≥ 7.0
Sigma rules6 YARA rules0
⬡

Weakness Classification

CWE-426Untrusted Search Path
CWE-427Uncontrolled Search Path Element
▤

Affected Products & Versions

1
nextcloud desktop>= 3.0.3 and < 3.3.0
◈

Sigma Hunt Rules

6
Exact rules name this CVE ID. Product rules name an affected product in their title. Related rules cover techniques used by actors who exploited this CVE. Showing the most relevant matches; the complete related set is on the full drill-down.
producthighUser Added to Remote Desktop Users Group
producthighNgrok Usage with Remote Desktop Service
productmediumInstallation of TeamViewer Desktop
productmediumDesktop.INI Created by Uncommon Process
productmediumPotential Remote Desktop Tunneling
productmediumNew Remote Desktop Connection Initiated Via Mstsc.EXE
▣

Scoring & Timeline

7.3
HIGH · CVSS v3.1 · security-advisories@github.com
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD18 Aug 2021 · 06:15 PM
CVSS VectorCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
🔗

References & Sources

3
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://github.com/nextcloud/desktop/pull/3497PatchThird Party Advisory
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-6q2w-v879-q24vThird Party Advisory
https://hackerone.com/reports/1240749Permissions RequiredThird Party Advisory
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