== Why is this an issue?

This rule raises an issue when:

* a JavaMail's ``++javax.mail.Session++`` is created with a ``++Properties++`` object having no ``++mail.smtp.ssl.checkserveridentity++`` or ``++mail.smtps.ssl.checkserveridentity++`` not configured to ``++true++``
* a Apache Common Emails's ``++org.apache.commons.mail.SimpleEmail++`` is used with ``++setSSLOnConnect(true)++`` or ``++setStartTLSEnabled(true)++`` or ``++setStartTLSRequired(true)++`` without a call to ``++setSSLCheckServerIdentity(true)++``


=== Noncompliant code example

[source,java]
----
Email email = new SimpleEmail();
email.setSmtpPort(465);
email.setAuthenticator(new DefaultAuthenticator(username, password));
email.setSSLOnConnect(true); // Noncompliant; setSSLCheckServerIdentity(true) should also be called before sending the email
email.send();
----

[source,java]
----
Properties props = new Properties();
props.put("mail.smtp.host", "smtp.gmail.com");
props.put("mail.smtp.socketFactory.port", "465");
props.put("mail.smtp.socketFactory.class", "javax.net.ssl.SSLSocketFactory"); // Noncompliant; Session is created without having "mail.smtp.ssl.checkserveridentity" set to true
props.put("mail.smtp.auth", "true");
props.put("mail.smtp.port", "465");
Session session = Session.getDefaultInstance(props, new javax.mail.Authenticator() {
  protected PasswordAuthentication getPasswordAuthentication() {
    return new PasswordAuthentication("username@gmail.com", "password");
  }
});
----


=== Compliant solution

[source,java]
----
Email email = new SimpleEmail();
email.setSmtpPort(465);
email.setAuthenticator(new DefaultAuthenticator(username, password));
email.setSSLOnConnect(true);
email.setSSLCheckServerIdentity(true); // Compliant
email.send();
----

[source,java]
----
Properties props = new Properties();
props.put("mail.smtp.host", "smtp.gmail.com");
props.put("mail.smtp.socketFactory.port", "465");
props.put("mail.smtp.socketFactory.class", "javax.net.ssl.SSLSocketFactory");
props.put("mail.smtp.auth", "true");
props.put("mail.smtp.port", "465");
props.put("mail.smtp.ssl.checkserveridentity", true); // Compliant
Session session = Session.getDefaultInstance(props, new javax.mail.Authenticator() {
  protected PasswordAuthentication getPasswordAuthentication() {
    return new PasswordAuthentication("username@gmail.com", "password");
  }
});
----

== Resources

* OWASP - https://owasp.org/www-project-top-ten/2017/A3_2017-Sensitive_Data_Exposure[Top 10 2017 Category A3 - Sensitive Data Exposure]
* CWE - https://cwe.mitre.org/data/definitions/297[CWE-297 - Improper Validation of Certificate with Host Mismatch]


ifdef::env-github,rspecator-view[]

'''
== Implementation Specification
(visible only on this page)

=== Message

Enable server identity validation on this SMTP SSL connection


=== Highlighting

Instantiation of the Session/Connection object


endif::env-github,rspecator-view[]
