Email is inherently a malicious traffic stream

It’s something many people don’t think about, but the majority of the traffic coming into the SMTP port is malicious. Spam is passively malicious, in that it just uses resources and bothers people. But there is a lot of actively malicious traffic coming into the SMTP port. Email is used as a vector to spread viruses and other malware. Email is also used for phishing and scamming. Many of the major hacks we’ve heard about over the last few years, including those in the email space, started with a single user getting infected through email.
We talk a lot about delivery here with clients and primarily focus on making sure their mail looks as unlike malicious mail as possible. We focus on spam filters, but every piece of mail goes through filters that also look for viruses, phishes, malware and other malicious traffic.
Mail servers are under attack constantly. The only reason our inboxes are useful is through the hard work of many people to filter out the bad and keep users from seeing the bulk of the mess attacking them.

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CNN warns about Target copy-cat phishes

Target did indeed do a blast to customers to offer one year of free credit monitoring. The problem is scammers are also on the prowl and are sending out similar emails.
Target even says it has identified and stopped at least 12 scams preying on consumers via email, Facebook and other outlets.CNN: Did you get an email from Target?

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Spam, Phish or Malware?

Some mornings I check mail from my phone. This showed up this morning.
PizzaHutMail
My first thought was “oh, no, Pizza Hut is spamming, wonder who sold them my address.”
Then I remembered that iOS is horrible and won’t show you anything other than the Friendly From and maybe it was some weird phishing scheme.
When I got to my real mail client I checked headers, and sure enough, it wasn’t really from Pizza Hut. I’m guessing actually malware, but I don’t have a forensics machine to click the link and I’m not doing it on anything I can’t wipe (and have isolated from the rest of my network).
The frustrating thing for me is that this is an authenticated email. It not from Pizza Hut, the address belongs to some company in France. Apparently, that company has had their systems cracked and malware sent through them. Fully authenticated malware, pretending to be Pizza Hut, and passing authentication on various devices.
Pizza Hut isn’t currently publishing a DMARC record, but in this case, a DMARC record for Pizza Hut wouldn’t matter. None of the email addresses in the headers point to Pizza Hut.
I spent last week listening to a lot of people discussing DMARC and authentication and protecting people from scams and headers. But those all the protocols in the world won’t protect against this kind of thing. Phishing and malware can’t be fixed by technology alone. Even if every domain on the planet published a p=reject policy, mail like this would still get through.
 
 
 

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Does email have a guarantee of delivery?

A client asked me earlier this week what SLAs ISPs provided for email delivery. The short answer is that there isn’t a SLA and that the only guarantee is that the email will get there when it gets there.
But as I was mentioning this to Steve, he pointed out that there was a recent change in the RFCs for email. In both RFC 821/2 and RFC 2821/2 (the original email related RFCs and the update in the early 2000’s) the RFCs stated that once a receiving MTA accepted an email that that MTA was required to either delivery the mail or generate an asynchronous bounce. While this isn’t a standard SLA, it does mean that a 2xy response after DATA meant the email would either be delivered to the user or be sent back to the sender. Despite the RFC requirements some receivers would still drop mail on the floor for various reasons, sometimes intentionally and sometimes not.
RFC 5321/2, the current SMTP standard, still says that once a server accepts the mail it must not lose that mail ‘for frivolous reasons.’ The RFC goes on to admit, though, that in recent years, SMTP servers are under a range of attacks and dropping mail on the floor is not frivolous in those cases.
 

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