Ecosyste.ms: Advisories

Security Advisories: MDE2OlNlY3VyaXR5QWR2aXNvcnlHSFNBLTIzZjctOTlqeC1tNTRy

Remote code execution in dependabot-core branch names when cloning

Impact

Remote code execution vulnerability in dependabot-common and dependabot-go_modules when a source branch name contains malicious injectable bash code.

For example, if Dependabot is configured to use the following source branch name: "/$({curl,127.0.0.1})", Dependabot will make a HTTP request to the following URL: 127.0.0.1 when cloning the source repository.

When Dependabot is configured to clone the source repository during an update, Dependabot runs a shell command to git clone the repository:

git clone --no-tags --no-recurse-submodules --depth=1 --branch=<BRANCH> --single-branch <GITHUB_REPO_URL> repo/contents/path

Dependabot will always clone the source repository for go_modules during the file fetching step and can be configured to clone the repository for other package managers using the FileFetcher class from dependabot-common.

source = Dependabot::Source.new(
  provider: "github",
  repo: "repo/name",
  directory: "/",
  branch: "/$({curl,127.0.0.1})",
)

repo_contents_path = "./file/path"
fetcher = Dependabot::FileFetchers.for_package_manager("bundler").
                  new(source: source, credentials: [],
                  repo_contents_path: repo_contents_path)
fetcher.clone_repo_contents

Patches

The fix was applied to version 0.125.1: https://github.com/dependabot/dependabot-core/pull/2727

Workarounds

Escape the branch name prior to passing it to the Dependabot::Source class.

For example using shellwords:

require "shellwords"
branch = Shellwords.escape("/$({curl,127.0.0.1})")
source = Dependabot::Source.new(
  provider: "github",
  repo: "repo/name",
  directory: "/",
  branch: branch,
)

Permalink: https://github.com/advisories/GHSA-23f7-99jx-m54r
JSON: https://advisories.ecosyste.ms/api/v1/advisories/MDE2OlNlY3VyaXR5QWR2aXNvcnlHSFNBLTIzZjctOTlqeC1tNTRy
Source: GitHub Advisory Database
Origin: Unspecified
Severity: High
Classification: General
Published: over 3 years ago
Updated: 6 months ago

CVSS Score: 8.7
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N

Identifiers: GHSA-23f7-99jx-m54r, CVE-2020-26222
References:

• https://github.com/dependabot/dependabot-core/security/advisories/GHSA-23f7-99jx-m54r
• https://github.com/dependabot/dependabot-core/pull/2727
• https://github.com/dependabot/dependabot-core/commit/e089116abbe284425b976f7920e502b8e83a61b5
• https://rubygems.org/gems/dependabot-common
• https://rubygems.org/gems/dependabot-omnibus
• https://nvd.nist.gov/vuln/detail/CVE-2020-26222
• https://github.com/rubysec/ruby-advisory-db/blob/master/gems/dependabot-omnibus/CVE-2020-26222.yml
• https://github.com/rubysec/ruby-advisory-db/blob/master/gems/dependabot-common/CVE-2020-26222.yml
• https://github.com/advisories/GHSA-23f7-99jx-m54r

Blast Radius: 19.1

Affected Packages