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Setup of Phish Threat in Office365

Hello,

I started to setup Phish Threat for my company but I've trouble with Office 365 that they are opening the E-Mails and links so they distort the reports.

I completely copied the settings of this user community.sophos.com/.../501783 but E-Mails were still blocked, Defender active and so on.

After that I created my own rules and everything works but it seems as if Office365 is opening the E-Mails and links as soon as they come in.

Any solution or idea what I did wrong?

PS: My company is located in germany.



Edited TAGs
[edited by: emmosophos at 7:04 PM (GMT -8) on 16 Feb 2024]
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  • MFR (Mail Flow Rules) and the configuration isn't any different in terms of exclusions. The only difference I can see is that Microsoft itself in it's documentation says that it does NOT do Secure by Default (high confidence phish detection) IF the MX does not point at M365.

    Because Microsoft wants to keep our customers secure by default, some tenants overrides are not applied for malware or high confidence phishing. These overrides include:

    • Allowed sender lists or allowed domain lists (anti-spam policies)
    • Outlook Safe Senders
    • IP Allow List (connection filtering)
    • Exchange mail flow rules (also known as transport rules)

    https://learn.microsoft.com/en-us/microsoft-365/security/office-365-security/secure-by-default?view=o365-worldwide

    Secure by default is not a setting that can be turned on or off,

    Exceptions:

    • Third-party filters: Secure by default only applies when the MX record for your domain is set to Exchange Online Protection (contoso.mail.protection.outlook.com). If it's set to another service or device, it is possible to override Secure by default with a Transport Rule to bypass all spam filtering. When Microsoft detects messages as High Confidence Phish with this rule in place, they still deliver to the Inbox.

    Saved you the trouble of clicking on the link, paraphrasing, there are more exceptions.

     

  • Hello Tom, thanks for your detailed answer.

    To be honest, i am just not sure what it does tell me in my scenario, which we already cleared.
    For now we still have the situation that we have a tenant with mx records pointing to micrsofft.

    We did all the exception from the script. Even the links does not get "rewritten" and seems "nomal" when hovering over them, but somehow OWA still redirects every click on those links to the Safe Link Engine and blocks the clicks.