CVE-2020-8903
A vulnerability in Google Cloud Platform's guest-oslogin versions between 20190304 and 20200507 allows a user that is only granted the role "roles/compute.osLogin" to escalate privileges to root. Using their membership to the "adm" group, users with this role are able to read the DHCP XID from the systemd journal. Using the DHCP XID, it is then possible to set the IP address and hostname of the instance to any value, which is then stored in /etc/hosts. An attacker can then point metadata.google.internal to an arbitrary IP address and impersonate the GCE metadata server which make it is possible to instruct the OS Login PAM module to grant administrative privileges. All images created after 2020-May-07 (20200507) are fixed, and if you cannot update, we recommend you edit /etc/group/security.conf and remove the "adm" user from the OS Login entry.
EPSS 0.09% · 26.0th percentile
Risk Scores
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Ubuntu:18.04:LTS | gce-compute-image-packages | 20190522-0ubuntu1~18.04.0, 0, * |
| Ubuntu:16.04:LTS | gce-compute-image-packages | *, 0, 20160930-0ubuntu3~16.04.0 |
| Ubuntu:14.04:LTS | gce-compute-image-packages | 20180905+dfsg1-0ubuntu1~14.04.0, 20180905+dfsg1-0ubuntu1~14.04.1, 20190315-0ubuntu1~14.04.0 |
| Ubuntu:20.04:LTS | gce-compute-image-packages | 0, 20190801-0ubuntu1, 20190801-0ubuntu4 |
Exploit Intelligence
- https://gitlab.com/gitlab-com/gl-security/gl-redteam/red-team-tech-notes/-/tree/master/oslogin-privesc-june-2020 (nist-nvd)
- https://github.com/GoogleCloudPlatform/guest-oslogin/pull/29 (circl)
- https://cloud.google.com/support/bulletins/#gcp-2020-008 (circl)
- openSUSE-SU-2020:0996 (circl)
- openSUSE-SU-2020:1014 (circl)
Timeline
- Jun 22, 2020 CVE Published
- Apr 14, 2021 EPSS Score
- Jun 23, 2021 EPSS Score
- Aug 24, 2021 EPSS Score
- Oct 26, 2021 EPSS Score
- Jan 6, 2022 EPSS Score
- Feb 4, 2022 EPSS Score
- Feb 28, 2022 EPSS Score
- Apr 1, 2022 EPSS Score
- May 1, 2022 EPSS Score
- Jul 3, 2022 EPSS Score
- Sep 4, 2022 EPSS Score
References
- https://ubuntu.com/security/CVE-2020-8903 third-party-advisory
- https://cloud.google.com/support/bulletins/#gcp-2020-008 third-party-advisory
- https://github.com/GoogleCloudPlatform/guest-oslogin/pull/29 third-party-advisory
- https://gitlab.com/gitlab-com/gl-security/gl-redteam/red-team-tech-notes/-/tree/master/oslogin-privesc-june-2020 third-party-advisory
- https://www.cve.org/CVERecord?id=CVE-2020-8903 third-party-advisory