HTTP: Apache CouchDB JSON Remote Privilege Escalation

This signature detects an attempt to exploit a privilege escalation vulnerability which has been reported in CouchDB. A remote, unauthenticated attacker could exploit this vulnerability by sending a crafted HTTP request to a vulnerable server. Successful exploitation could result in an unauthorized user gaining access to CouchDB.

Extended Description

Due to differences in the Erlang-based JSON parser and JavaScript-based JSON parser, it is possible in Apache CouchDB before 1.7.0 and 2.x before 2.1.1 to submit _users documents with duplicate keys for 'roles' used for access control within the database, including the special case '_admin' role, that denotes administrative users. In combination with CVE-2017-12636 (Remote Code Execution), this can be used to give non-admin users access to arbitrary shell commands on the server as the database system user. The JSON parser differences result in behaviour that if two 'roles' keys are available in the JSON, the second one will be used for authorising the document write, but the first 'roles' key is used for subsequent authorization for the newly created user. By design, users can not assign themselves roles. The vulnerability allows non-admin users to give themselves admin privileges.

Affected Products

Apache couchdb

References

BugTraq: 101868

CVE: CVE-2017-12635

Short Name

HTTP:APACHE:JSON-PRIV-ESC

Severity

Major

Recommended

True

Recommended Action

Drop

HTTP: Apache CouchDB JSON Remote Privilege Escalation

Extended Description

Affected Products

References

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