CVE-2018-1085
Public on
Last Modified:
Description
OpenShift and Atomic Enterprise Ansible deploys a misconfigured etcd file that causes the SSL client certificate authentication to be disabled. Quotations around the values of ETCD_CLIENT_CERT_AUTH and ETCD_PEER_CLIENT_CERT_AUTH in etcd.conf result in etcd being configured to allow remote users to connect without any authentication if they can access the etcd server bound to the network on the master nodes. An attacker could use this flaw to read and modify all the data about the Openshift cluster in the etcd datastore, potentially adding another compute node, or bringing down the entire cluster.
Statement
Mitigation
On master nodes where etcd has been installed using the container method:
0. Verify you can connect to etcd without providing TLS authentication credentials. On any master node, check the ETCD_LISTEN_CLIENT_URLS in /etc/etcd/etcd.conf, and use one of the client urls to connect without providing a certificate, eg:
curl -4 curl https://10.0.1.1:2379/version -k
0a. If vulnerable output will show something like this:
{"etcdserver":"3.2.15","etcdcluster":"3.2.0"}
0b. If not affected the connection will fail with:
curl: (58) NSS: client certificate not found (nickname not specified)
1. update /etc/etcd/etcd.conf on the master nodes to remove quotes from these fields:
ETCD_PEER_CLIENT_CERT_AUTH="true"
ETCD_CLIENT_CERT_AUTH="true"
eg.
ETCD_PEER_CLIENT_CERT_AUTH=true
ETCD_CLIENT_CERT_AUTH=true
2. Restart the etcd container service:
sudo systemctl restart etcd_container
3. Test if client authentication is now required using the steps from 0. above.
Additional information
- Bugzilla 1557822: openshift-ansible: Incorrectly quoted values in etcd.conf causes disabling of SSL client certificate authentication
- CWE-287: Improper Authentication
- FAQ: Frequently asked questions about CVE-2018-1085
Common Vulnerability Scoring System (CVSS) Score Details
Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
Red Hat | NVD | |
---|---|---|
CVSS v3 Base Score | 9 | 9.8 |
Attack Vector | Adjacent Network | Network |
Attack Complexity | Low | Low |
Privileges Required | Low | None |
User Interaction | None | None |
Scope | Changed | Unchanged |
Confidentiality Impact | High | High |
Integrity Impact | High | High |
Availability Impact | High | High |
CVSS v3 Vector
Red Hat: CVSS:3.0/AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
NVD: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Acknowledgements
Red Hat would like to thank David Hocky (Comcast) for reporting this issue.
Frequently Asked Questions
Why is Red Hat's CVSS v3 score or Impact different from other vendors?
For more information, see https://access.redhat.com/solutions/762393.
My product is listed as "Under investigation" or "Affected", when will Red Hat release a fix for this vulnerability?
- "Under investigation" doesn't necessarily mean that the product is affected by this vulnerability. It only means that our Analysis Team is still working on determining whether the product is affected and how it is affected.
- "Affected" means that our Analysis Team has determined that this product is affected by this vulnerability and might release a fix to address this in the near future.
What can I do if my product is listed as "Will not fix"?
Available options depend mostly on the Impact of the vulnerability and the current Life Cycle phase of your product. Overall, you have the following options:
- Upgrade to a supported product version that includes a fix for this vulnerability (recommended).
- Apply a mitigation (if one exists).
- Open a support case to request a prioritization of releasing a fix for this vulnerability.
What can I do if my product is listed as "Fix deferred"?
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- Apply a mitigation (if one exists).
- Open a support case to request a prioritization of releasing a fix for this vulnerability.
- Red Hat Engineering focuses on addressing high-priority issues based on their complexity or limited lifecycle support. Therefore, lower-priority issues will not receive immediate fixes.
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I have a Red Hat product but it is not in the above list, is it affected?
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