# CVE-2020-5415: Concourse's GitLab auth allows impersonation > Attackers can impersonate authorized users by matching their full name in GitLab, bypassing access controls in Concourse CI installations using GitLab auth. - **Severity:** Critical 10.0 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:L`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 12 Aug 2020 - **Updated:** 16 Sep 2024 - **Also known as:** BIT-concourse-2020-5415, GHSA-627p-rr78-99rj ## What is CVE-2020-5415? CVE-2020-5415 is a critical authentication bypass vulnerability in VMware Tanzu Concourse, published on 12 Aug 2020. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description Concourse, versions prior to 6.3.1 and 6.4.1, in installations which use the GitLab auth connector, is vulnerable to identity spoofing by way of configuring a GitLab account with the same full name as another user who is granted access to a Concourse team. GitLab groups do not have this vulnerability, so GitLab users may be moved into groups which are then configured in the Concourse team. Weakness: CWE-290 (Authentication Bypass by Spoofing) ## Which versions are affected by CVE-2020-5415? 15 open source packages ship an affected version, including github.com/concourse/concourse, concourse and github.com/concourse/dex. It affects 1 product. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `github.com/concourse/concourse` | Go | All versions | 0.0.0-20200730151558-b00d1c8d8576 | | `github.com/concourse/concourse` | Go | All versions | 0.0.0-20200730151558-b00d1c8d8576 | | `github.com/concourse/concourse` | Go | From 0.0.0 | 1.6.1-0.20200730151558-b00d1c8d8576 | | `github.com/concourse/concourse` | Go | From 0.0.0 | 1.6.1-0.20200730151558-b00d1c8d8576 | | `github.com/concourse/concourse` | Go | From 1.6.1 | 6.3.1 | | `github.com/concourse/concourse` | Go | From 1.6.1 | 6.3.1 | | `github.com/concourse/concourse` | Go | From 6.4.0 | 6.4.1 | | `github.com/concourse/concourse` | Go | From 6.4.0 | 6.4.1 | | `concourse` | Bitnami | All versions | 6.3.1, 6.4.1 | | `github.com/concourse/dex` | Go | All versions | 0.0.0-20200730150203-821b48abfd88 | | `github.com/concourse/dex` | Go | All versions | 0.0.0-20200730150203-821b48abfd88 | | `github.com/concourse/dex` | Go | From 0.0.0 | 6.3.1 | | `github.com/concourse/dex` | Go | From 0.0.0 | 6.3.1 | | `github.com/concourse/dex` | Go | From 6.4.0 | 6.4.1 | | `github.com/concourse/dex` | Go | From 6.4.0 | 6.4.1 | Products: Pivotal Software Concourse. ## How do I fix CVE-2020-5415? Upgrade github.com/concourse/concourse to a fixed version for your release line: 0.0.0-20200730151558-b00d1c8d8576, 1.6.1-0.20200730151558-b00d1c8d8576, 6.3.1 or 6.4.1. ## Is CVE-2020-5415 being exploited? There is no known exploitation of CVE-2020-5415 in the wild and no public exploit code. ## Other vulnerabilities in VMware Tanzu Concourse - [CVE-2020-5409](https://insights.sbomify.com/CVE-2020-5409/): Concourse Open Redirect in the /sky/login endpoint (high 7.6) - [CVE-2018-15798](https://insights.sbomify.com/CVE-2018-15798/): Pivotal Concourse allows malicious redirect urls on login (high 7.6) - [CVE-2018-1227](https://insights.sbomify.com/CVE-2018-1227/): Supply chain in Concourse CI: As of 2018-03-13, Pivotal does not believe that any resources or builds of Concourse have been compromised. (high 7.5) - [CVE-2019-3792](https://insights.sbomify.com/CVE-2019-3792/): Concourse 5.0.0 SQL Injection vulnerability (medium 6.8) - [CVE-2022-31683](https://insights.sbomify.com/CVE-2022-31683/): Team scope authorization bypass when Post/Put request with :team_name in body, allows HTTP parameter pollution (medium 5.4) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2020-5415 and fix it if it is affected. What it is: CVE-2020-5415 is a critical authentication bypass vulnerability in VMware Tanzu Concourse, published on 12 Aug 2020. An attacker can exploit it over the internet without logging in, with no action from the victim. Exploitation: There is no known exploitation of CVE-2020-5415 in the wild and no public exploit code. Affected packages and fixed versions: - github.com/concourse/concourse (Go): affected all versions; fixed in 0.0.0-20200730151558-b00d1c8d8576 - github.com/concourse/concourse (Go): affected all versions; fixed in 0.0.0-20200730151558-b00d1c8d8576 - github.com/concourse/concourse (Go): affected from 0.0.0; fixed in 1.6.1-0.20200730151558-b00d1c8d8576 - github.com/concourse/concourse (Go): affected from 0.0.0; fixed in 1.6.1-0.20200730151558-b00d1c8d8576 - github.com/concourse/concourse (Go): affected from 1.6.1; fixed in 6.3.1 - github.com/concourse/concourse (Go): affected from 1.6.1; fixed in 6.3.1 - github.com/concourse/concourse (Go): affected from 6.4.0; fixed in 6.4.1 - github.com/concourse/concourse (Go): affected from 6.4.0; fixed in 6.4.1 - concourse (Bitnami): affected all versions; fixed in 6.3.1, 6.4.1 - github.com/concourse/dex (Go): affected all versions; fixed in 0.0.0-20200730150203-821b48abfd88 - github.com/concourse/dex (Go): affected all versions; fixed in 0.0.0-20200730150203-821b48abfd88 - github.com/concourse/dex (Go): affected from 0.0.0; fixed in 6.3.1 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-2020-5415/ (Markdown: https://insights.sbomify.com/CVE-2020-5415/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2020-5415 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-5415 - OSV: https://osv.dev/vulnerability/CVE-2020-5415 --- From sbomify Insights: https://insights.sbomify.com/CVE-2020-5415/ Summaries are generated and may contain mistakes; the official description above is the record.