An issue was discovered in Couchbase Server before 6.0.5, 6.1.x through 6.5.x before 6.5.2, and 6.6.x before 6.6.1. An internal user with administrator privileges, @ns_server, leaks credentials in cleartext in the cbcollect_info.log, debug.log, ns_couchdb.log, indexer.log, and stats.log files. NOTE: updating the product does not automatically address leaks that occurred in the past.

Exposed Erlang Cookie could lead to Remote Command Execution (RCE) attack. Communication between Erlang nodes is done by exchanging a shared secret (aka "magic cookie"). There are cases where the magic cookie is included in the content of the logs. An attacker can use the cookie to attach to an Erlang node and run OS level commands on the system running the Erlang node. Affects version: 6.5.1. Fix version: 6.6.0.

In Couchbase Server 6.0, credentials cached by a browser can be used to perform a CSRF attack if an administrator has used their browser to check the results of a REST API request.

Couchbase Server Java SDK before 2.7.1.1 allows a potential attacker to forge an SSL certificate and pose as the intended peer. An attacker can leverage this flaw by crafting a cryptographically valid certificate that will be accepted by Java SDK's Netty component due to missing hostname verification.

In Couchbase Server 6.0.3 and Couchbase Sync Gateway through 2.7.0, the Cluster management, views, query, and full-text search endpoints are vulnerable to the Slowloris denial-of-service attack because they don't more aggressively terminate slow connections.

Couchbase Server 4.0.0, 4.1.0, 4.1.1, 4.5.0, 4.5.1, 4.6.0 through 4.6.5, 5.0.0, 5.1.1, 5.5.0 and 5.5.1 have Insecure Permissions for the projector and indexer REST endpoints (they allow unauthenticated access).The /settings REST endpoint exposed by the projector process is an endpoint that administrators can use for various tasks such as updating configuration and collecting performance profiles. The endpoint was unauthenticated and has been updated to only allow authenticated users to access these administrative APIs.

In Couchbase Server 5.0.0, when an invalid Remote Cluster Certificate was entered as part of the reference creation, XDCR did not parse and check the certificate signature. It then accepted the invalid certificate and attempted to use it to establish future connections to the remote cluster. This has been fixed in version 5.5.0. XDCR now checks the validity of the certificate thoroughly and prevents a remote cluster reference from being created with an invalid certificate.

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 Couchbase Server 5.1.1, the cookie used for intra-node communication was not generated securely. Couchbase Server uses erlang:now() to seed the PRNG which results in a small search space for potential random seeds that could then be used to brute force the cookie and execute code against a remote system. This has been fixed in version 6.0.0.

In Couchbase Server 4.6.3 and 5.5.0, secondary indexing encodes the entries to be indexed using collatejson. When index entries contain certain characters like \t, <, >, it caused buffer overrun as encoded string would be much larger than accounted for, causing indexer service to crash and restart. This has been remedied in versions 5.1.2 and 5.5.2 to ensure buffer always grows as needed for any input.