Microsoft 365 - Learn about junk email and phishing

Mail identified as possible junk email by campus junk mail filtering is automatically moved to the Junk Email folder, and any potentially dangerous content within the message, for example, links or executable code, is disabled.

Microsoft 365 Junk Mail Filtering Recommendation: It is the recommendation of the Microsoft 365 team for users to disable all local client (Outlook, Apple Mail, etc.) automated junk mail filters and local client rules/filters when configuring your UW-Madison Microsoft 365 account. For UW-Madison users, many clients will have local junk mail filtering disabled entirely. All rules/filters should be created in Outlook on the web. Please refer to our Microsoft 365 (Outlook on the web | Outlook for Windows/MacOS) - Using Inbox Rules document.


 

Types of junk email

Junk Email

Junk email, also known as spam, is unsolicited email, usually commercial. It can strain networks, clog email servers, and fill mailboxes with unwanted and possibly offensive messages and images. Most of it is annoying, but harmless. Most junk email will be blocked by the email server that hosts your account.

Phishing

Phishing is a specific kind of junk email that's used to obtain private information for use in identity theft and other scams. The email message appears to come from a trusted source, such as your bank, and often includes the actual business logo and an apparently legitimate reply address.

For more information about how to identify phishing email messages and how to protect yourself from them, see Learn how to recognize and report phishing.

"Graymail" or Bulk Mail

"Graymail" (of bulk mail) is generally characterized by newsletters, sales pitches, and stuff trying to pass as legitimate marketing. It's a result of your address(es) getting on marketing lists, and then being sold to other email marketers. These messages are particularly difficult to get classified as spam because they are usually being sent on behalf of otherwise legitimate companies (for varying degrees of "legitimate"), and there are many recipients who consider the messages completely legitimate.

Backscatter

'Backscatter' is the name given to bounceback messages generated when a spammer uses your mail address in the 'From:' line of their messages. This does not mean they have access to your account, however, if you feel your account has been compromised, please change your password. If the spammer's message can't be delivered for any reason, the receiving host will send back a bounce or non-delivery report to the address in the 'From:' line.

Backscatter messages takes several forms:

  • DSN (Delivery Status Notification) advising that the message cannot be delivered - or that delivery is delayed.
  • Auto-replies - often advising that the mailbox is no longer in use due to spam or that the recipient is on vacation.
  • Challenge/response requesting that you confirm you sent the message.

If a spammer sends a large number of messages, you may receive literally hundreds or thousands of 'backscatter' messages.

Spoofing

When a spammer uses your address as the "From" address, but they are not sending from your account, this is called 'Spoofing.' This means that they are just using your address so it appears that you sent the message, though the header information will often display the true sending address. For more information about 'Spoofing', please review this article: http://lifehacker.com/how-spammers-spoof-your-email-address-and-how-to-prote-1579478914.

Important: There is not a way to stop 'Backscatter' or 'Spoofing' from occurring. However, spammers will eventually switch addresses, not out of respect for you, but simply because if they use the same address or domain for too long, spam filters will eventually start blocking it.

FAQ

   

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Keywords:
microsoft office o365 m365 microsoft 365 web client outlook web app help calendaring overview messages categories flags color reminding arranging filtering junk email phishing spam owa whitelisting block senders safe inbox rules filters client windows mac 2019 2016 2019 mac windows graymail backscatter spoofing proofpoint proof point
Doc ID:
31866
Owned by:
O365 S. in Microsoft 365
Created:
2013-07-26
Updated:
2024-12-27
Sites:
DoIT Help Desk, Microsoft 365