# CVE-2020-8903: Priviged Escalation in Google Cloud Platform's Guest-OSLogin

> Attackers with OS Login role can escalate to root by impersonating the metadata server via DHCP XID manipulation in GCP instances.

- **Severity:** High 7.3 (`CVSS:4.0/AV:L/AC:H/AT:N/PR:L/UI:A/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 22 Jun 2020
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-29mh-jw46-2rf9, UBUNTU-CVE-2020-8903

## What is CVE-2020-8903?

CVE-2020-8903 is a high-severity vulnerability in Opensuse Leap, published on 22 Jun 2020. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official 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.

Weakness: CWE-276 (Incorrect Default Permissions)

## Which versions are affected by CVE-2020-8903?

It affects 2 products.


Products: Google Guest-Oslogin, Opensuse Leap.

## How do I fix CVE-2020-8903?

Upgrade to a fixed version.

## Is CVE-2020-8903 being exploited?

There is no known exploitation of CVE-2020-8903 in the wild and no public exploit code.

## Other vulnerabilities in Opensuse Leap

- [CVE-2020-8907](https://insights.sbomify.com/CVE-2020-8907/): Priviged Escalation in Google Cloud Platform's Guest-OSLogin (critical 9.3)
- [CVE-2020-8933](https://insights.sbomify.com/CVE-2020-8933/): Priviged Escalation in Google Cloud Platform's Guest-OSLogin (critical 9.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-8903 and fix it if it is affected.

What it is: CVE-2020-8903 is a high-severity vulnerability in Opensuse Leap, published on 22 Jun 2020. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2020-8903 in the wild and no public exploit code.

Affected product: Opensuse Leap. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2020-8903/ (Markdown: https://insights.sbomify.com/CVE-2020-8903/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-8903
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-8903
- OSV: https://osv.dev/vulnerability/CVE-2020-8903

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-8903/
Summaries are generated and may contain mistakes; the official description above is the record.