#VU27957 Authorization bypass through user-controlled key in Nextcloud Server - CVE-2020-8154

Vulnerability identifier: #VU27957

Vulnerability risk: Medium

CVSSv4.0: 2.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2020-8154

CWE-ID: N/A

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Nextcloud Server
Client/Desktop applications / Messaging software

Vendor: Nextcloud

Description

The vulnerability allows a remote attacker to wipe devices of other users.

The vulnerability exists due to insecure direct object reference in Nextcloud Server. A remote attacker can send specially crafted request directory to the affected endpoint and remotely wipe devices of other users.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Nextcloud Server: 18.0.0 - 18.0.2

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External links
https://lists.opensuse.org/opensuse-security-announce/2020-05/msg00037.html
https://lists.opensuse.org/opensuse-security-announce/2020-05/msg00038.html
https://hackerone.com/reports/819807
https://nextcloud.com/security/advisory/?id=NC-SA-2020-018

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.