Improper Restriction of Excessive Authentication Attempts in Nextcloud Server and Enterprise Server

1) Improper Restriction of Excessive Authentication Attempts

EUVDB-ID: #VU82082

Risk: Medium

CVSSv3.1: 4.4 [CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2023-39960

CWE-ID: CWE-307 - Improper Restriction of Excessive Authentication Attempts

Exploit availability: No

Description

The vulnerability allows a remote attacker to compromise the target system.

The vulnerability exists due to the number of login attempts is not limited within the WebDAV endpoint. A remote user can perform a brute-force attack.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Nextcloud Enterprise Server: 22.0.0 - 26.0.3

Nextcloud Server: 25.0.0 - 26.0.3

External links

http://hackerone.com/reports/1924212
http://github.com/nextcloud/security-advisories/security/advisories/GHSA-2hrc-5fgp-c9c9
http://github.com/nextcloud/server/pull/38046

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

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