CVE-2016-9463: nextcloud nextcloud_server

Vulnerability summary

CVE-2016-9463 is a high (CVSS 8.1) vulnerability in nextcloud nextcloud_server. EPSS estimates a 4.09% chance of exploitation in the next 30 days, higher than 90.6% of scored vulnerabilities. 2 public exploits are recorded.

Timeline

1. 28-03-2017
   PublishedVulnerability first disclosed.
2. 06-08-2024
   Last modifiedVulnerability information updated.

Description

Nextcloud Server before 9.0.54 and 10.0.1 & ownCloud Server before 9.1.2, 9.0.6, and 8.2.9 suffer from SMB User Authentication Bypass. Nextcloud/ownCloud include an optional and not by default enabled SMB authentication component that allows authenticating users against an SMB server. This backend is implemented in a way that tries to connect to a SMB server and if that succeeded consider the user logged-in. The backend did not properly take into account SMB servers that have any kind of anonymous auth configured. This is the default on SMB servers nowadays and allows an unauthenticated attacker to gain access to an account without valid credentials. Note: The SMB backend is disabled by default and requires manual configuration in the Nextcloud/ownCloud config file. If you have not configured the SMB backend then you're not affected by this vulnerability.

• CWE-303Incorrect Implementation of Authentication AlgorithmThe requirements for the product dictate the use of an established authentication algorithm, but the implementation of the algorithm is incorrect.
• CWE-287Improper AuthenticationWhen an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.