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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.32%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
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.
- CVSS 4.0
- 7.3 HIGHCVSS:4.0/AV:L/AC:H/AT:N/PR:L/UI:A/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 0.32% probability · 24th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-276
- Affected
- google/guest-oslogin · opensuse/leap
- Source
- cve-coordination@google.com
References
- http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00037.htmlMailing List, Third Party Advisory
- http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00047.htmlMailing List, Third Party Advisory
- https://cloud.google.com/support/bulletins/#gcp-2020-008Vendor Advisory
- https://github.com/GoogleCloudPlatform/guest-oslogin/pull/29Patch, Third Party Advisory
- https://gitlab.com/gitlab-com/gl-security/gl-redteam/red-team-tech-notes/-/tree/master/oslogin-privesc-june-2020Exploit, Third Party Advisory
- http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00037.htmlMailing List, Third Party Advisory
- http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00047.htmlMailing List, Third Party Advisory
- https://cloud.google.com/support/bulletins/#gcp-2020-008Vendor Advisory
- https://github.com/GoogleCloudPlatform/guest-oslogin/pull/29Patch, Third Party Advisory
- https://gitlab.com/gitlab-com/gl-security/gl-redteam/red-team-tech-notes/-/tree/master/oslogin-privesc-june-2020Exploit, Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.