do not require smtp login and starttls if there is no password/userna…

…me provided (#641)

README.md

@@ -90,8 +90,6 @@ When configuring outgoing SMTP please consider the following:
 
 Restrictions:
 * no other provider like Mailgun or Sendgrid must be configured for this to work
-* only supports StartTLS right now (you have to use the corresponding port)
-* no anonymous SMTP is supported right now (you have to use a username/password to authenticate)
 * For AWS SES `CANARY_ALERT_EMAIL_FROM_DISPLAY` should be in the format: `CANARY_ALERT_EMAIL_FROM_DISPLAY=CanaryAlert <[email protected]>`
 
 The following settings have to be configured in `switchboard.env` for SMTP to work:

canarytokens/channel_output_email.py

@@ -263,8 +263,9 @@ def smtp_send(
         smtpmsg.attach(part2)
 
         with smtplib.SMTP(smtp_server, smtp_port) as server:
-            server.starttls()
-            server.login(smtp_username, smtp_password)
+            if smtp_username is not None and smtp_password is not None:
+                server.starttls()
+                server.login(smtp_username, smtp_password)
             server.sendmail(fromaddr, toaddr, smtpmsg.as_string())
     except smtplib.SMTPException as e:
         log.error("A smtp error occurred: %s - %s" % (e.__class__, e))