Privilege escalation in Apache Couchdb
CVE-2017-12635
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.
Vulnerability class: Privilege Escalation
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.998 (100.0th percentile), scored .
Very high probability of exploitation in the next 30 days — among the top 0.1% most-likely-to-be-exploited CVEs. 100th percentile — 100.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.997 · newest: 0.998 · change: +0.001
Affected products
- Apache Couchdb — versions 2.0.0
- Apache Software Foundation Couchdb — versions 1.2.0 to 1.6.1, 2.0.0 to 2.1.0
Weakness classification (CWE)
Public proof-of-concept exploits
References
- www.exploit-db.com/exploits/44498/ (exploit)
- www.exploit-db.com/exploits/45019/ (exploit)
- lists.apache.org/thread.html/6c405bf3f8358e6314076be9f48c89a2e0ddf00539906291eb… (mailing-list)
- security.gentoo.org/glsa/201711-16 (vendor-advisory, Third Party Advisory)
- lists.debian.org/debian-lts-announce/2018/01/msg00026.html (mailing-list)
- www.securityfocus.com/bid/101868 (VDB Entry, Third Party Advisory, vdb-entry)
- support.hpe.com/hpsc/doc/public/display
Frequently asked questions
- What is CVE-2017-12635?
- CVE-2017-12635 is a critical-severity vulnerability in Apache Couchdb, classified under Improper Privilege Management. CVSS score: 9.8/10. Published 2017-11-14.
- How severe is CVE-2017-12635?
- Critical severity. CVSS v3 base score is 9.8 out of 10.
- Is CVE-2017-12635 known to be exploited?
- 54 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.