# CVE-2018-10933: Auth bypass in libssh

> A malicious client can bypass authentication in libssh server to create channels and gain unauthorized access to the system.

- **Severity:** Critical 9.1 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 17 Oct 2018
- **Updated:** 5 Aug 2024
- **Also known as:** ALPINE-CVE-2018-10933, DEBIAN-CVE-2018-10933, DLA-1548-1, DSA-4322-1, GHSA-22gf-f5w4-hrfq, MGASA-2019-0043, RHBA-2018:3712, SUSE-SU-2018:3162-1, SUSE-SU-2018:3253-1, UBUNTU-CVE-2018-10933, USN-3795-1

## What is CVE-2018-10933?

CVE-2018-10933 is a critical authentication bypass vulnerability in Canonical Ubuntu Linux, published on 17 Oct 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability was found in libssh's server-side state machine before versions 0.7.6 and 0.8.4. A malicious client could create channels without first performing authentication, resulting in unauthorized access.

Weakness: CWE-287 (Improper Authentication), CWE-592 (DEPRECATED: Authentication Bypass Issues)

## Which versions are affected by CVE-2018-10933?

It affects 9 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `cockpit` | Red Hat:rhel_extras_other:7 | All versions | 0:176-4.el7 |
| `cockpit-dashboard` | Red Hat:rhel_extras_other:7 | All versions | 0:176-4.el7 |
| `cockpit-docker` | Red Hat:rhel_extras_other:7 | All versions | 0:176-4.el7 |
| `cockpit-machines` | Red Hat:rhel_extras_other:7 | All versions | 0:176-4.el7 |
| `cockpit-packagekit` | Red Hat:rhel_extras_other:7 | All versions | 0:176-4.el7 |
| `cockpit-pcp` | Red Hat:rhel_extras_other:7 | All versions | 0:176-4.el7 |
| `cockpit-storaged` | Red Hat:rhel_extras_other:7 | All versions | 0:176-4.el7 |
| `libssh` | Red Hat:rhel_extras_other:7 | All versions | 0:0.7.1-7.el7 |
| `libssh-debuginfo` | Red Hat:rhel_extras_other:7 | All versions | 0:0.7.1-7.el7 |
| `libssh-devel` | Red Hat:rhel_extras_other:7 | All versions | 0:0.7.1-7.el7 |
| `libssh` | SUSE:Linux Enterprise Desktop 12 SP3 | All versions | 0.6.3-12.6.1 |
| `libssh` | SUSE:Linux Enterprise Module for Basesystem 15 | All versions | 0.7.5-6.3.1 |
| `libssh` | SUSE:Linux Enterprise Software Development Kit 12 SP3 | All versions | 0.6.3-12.6.1 |
| `libssh` | SUSE:Linux Enterprise Workstation Extension 12 SP3 | All versions | 0.6.3-12.6.1 |

Products: Canonical Ubuntu Linux, Debian Debian Linux, Libssh Libssh, Netapp Oncommand Unified Manager, Netapp Oncommand Workflow Automation, Netapp Snapcenter, Netapp Storage Automation Store, Oracle Mysql Workbench, Redhat Enterprise Linux.

## How do I fix CVE-2018-10933?

Upgrade to a fixed version.

## Is CVE-2018-10933 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2018-10933 exists.

Public exploit code:

- Spawn to shell without any credentials by using CVE-2018-10933 (LibSSH) (github_poc): https://github.com/blacknbunny/CVE-2018-10933
- Script to identify hosts vulnerable to CVE-2018-10933 (github_poc): https://github.com/jobroche/libssh-scanner
- CVE-2018-10933 very simple POC (github_poc): https://github.com/SoledaD208/CVE-2018-10933
- cve-2018-10933 libssh authentication bypass (github_poc): https://github.com/hackerhouse-opensource/cve-2018-10933
- libssh CVE-2018-10933 (github_poc): https://github.com/jas502n/CVE-2018-10933
- Leveraging it is a simple matter of presenting the server with the  SSH2_MSG_USERAUTH_SUCCESS message, which shows that the login already occurred without a problem.  The server expects the message SSH2_MSG_USERAUTH_REQUEST to start the authentication procedure, but by skipping it an attacker can log in without showing any credentials. (github_poc): https://github.com/kn6869610/CVE-2018-10933

## Other vulnerabilities in Canonical Ubuntu Linux

- [CVE-2020-11651](https://insights.sbomify.com/CVE-2020-11651/): SaltStack Salt Authentication Bypass (critical 9.8, exploited in the wild)
- [CVE-2020-7247](https://insights.sbomify.com/CVE-2020-7247/): OpenSMTPD Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2019-16928](https://insights.sbomify.com/CVE-2019-16928/): Exim Out-of-bounds Write (critical 9.8, exploited in the wild)
- [CVE-2018-6789](https://insights.sbomify.com/CVE-2018-6789/): Exim Buffer Overflow (critical 9.8, exploited in the wild)
- [CVE-2015-2590](https://insights.sbomify.com/CVE-2015-2590/): Oracle Java SE and Java SE Embedded Remote Code Execution (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-10933 and fix it if it is affected.

What it is: CVE-2018-10933 is a critical authentication bypass vulnerability in Canonical Ubuntu Linux, published on 17 Oct 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2018-10933 exists.

Affected product: Canonical Ubuntu Linux. 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-2018-10933/ (Markdown: https://insights.sbomify.com/CVE-2018-10933/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-10933
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-10933
- OSV: https://osv.dev/vulnerability/CVE-2018-10933

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-10933/
Summaries are generated and may contain mistakes; the official description above is the record.