CVE-2019-11496 - Improper Authentication

Severity

90%

Complexity

39%

Confidentiality

86%

In versions of Couchbase Server prior to 5.0, the bucket named "default" was a special bucket that allowed read and write access without authentication. As part of 5.0, the behavior of all buckets including "default" were changed to only allow access by authenticated users with sufficient authorization. However, users were allowed unauthenticated and unauthorized access to the "default" bucket if the properties of this bucket were edited. This has been fixed in versions 5.1.0 and 5.5.0.

In versions of Couchbase Server prior to 5.0, the bucket named "default" was a special bucket that allowed read and write access without authentication. As part of 5.0, the behavior of all buckets including "default" were changed to only allow access by authenticated users with sufficient authorization. However, users were allowed unauthenticated and unauthorized access to the "default" bucket if the properties of this bucket were edited. This has been fixed in versions 5.1.0 and 5.5.0.

CVSS 3.1 Base Score 9.1. CVSS Attack Vector: network. CVSS Attack Complexity: low. CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N).

CVSS 2.0 Base Score 6.4. CVSS Attack Vector: network. CVSS Attack Complexity: low. CVSS Vector: (AV:N/AC:L/Au:N/C:P/I:P/A:N).

Demo Examples

Improper Authentication

CWE-287

The following code intends to ensure that the user is already logged in. If not, the code performs authentication with the user-provided username and password. If successful, it sets the loggedin and user cookies to "remember" that the user has already logged in. Finally, the code performs administrator tasks if the logged-in user has the "Administrator" username, as recorded in the user cookie.


               
}
}
ExitError("Error: you need to log in first");
);
);
DoAdministratorTasks();

Unfortunately, this code can be bypassed. The attacker can set the cookies independently so that the code does not check the username and password. The attacker could do this with an HTTP request containing headers such as:


               
[body of request]

By setting the loggedin cookie to "true", the attacker bypasses the entire authentication check. By using the "Administrator" value in the user cookie, the attacker also gains privileges to administer the software.

Improper Authentication

CWE-287

Overview

First reported 5 years ago

2019-09-10 18:15:00

Last updated 5 years ago

2019-09-26 18:15:00

Affected Software

Couchbase Server -

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