CVE-2017-12635 Information

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.

CVSS Vector

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Reference

http://www.securityfocus.com/bid/101868 https://lists.apache.org/thread.html/6c405bf3f8358e6314076be9f48c89a2e0ddf00539906291ebdf0c67@3Cdev.couchdb.apache.org3E https://lists.debian.org/debian-lts-announce/2018/01/msg00026.html https://security.gentoo.org/glsa/201711-16 https://support.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbmu03935en_us https://www.exploit-db.com/exploits/44498/ https://www.exploit-db.com/exploits/45019/

Attack Complexity

LOW

Privileges Required

NONE

User Interaction Required

NONE

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

HIGH

Availability Impact

HIGH

Base Score

HIGH

Base Severity

9.8