What about the botnets?!

Botnets are a huge problem for a number of reasons. Not only are they used to send spam, they’re also used in criminal activities. One of the major challenges in dealing with botnets is finding and stopping the people who create and use them. Why? Because the internet is global and crime tends to be prosecuted within local jurisdictions.

White Collar Crime.
Catching someone running a botnet, or involved in crime online in general, requires cooperation from authorities in multiple jurisdictions. Police, lawyers, and other officials have had to create relationships to work together, all while respecting international law. It’s a involved and complicated process, and that’s before we talk about the challenges in actually figuring out who is running the botnet. Subject matter experts, like operating system manufacturers or anti-virus companies, are also part of the process in most cases. (Read about the Simda botnet takedown at Interpol)
Despite the challenges, botnets do get taken down and criminals do get arrested and brought to justice. Today the Department of Justice announced a guilty plea from a Russian citizen charged with infecting machines with malware.

Senakh and his co-conspirators used the Ebury botnet to generate and redirect internet traffic in furtherance of various click-fraud and spam e-mail schemes, which fraudulently generated millions of dollars in revenue. As part of the plea, Senakh admitted that he supported the criminal enterprise by creating accounts with domain registrars which helped build the Ebury botnet infrastructure and personally profited from traffic generated by the Ebury botnet.

Ebury is kinda interesting because it’s actually a Linux botnet, not a Windows one. It used a SSH exploit to get in, stole user credentials and then smuggled the credentials out in special TCP packets. CERT-BUND has some of the gritty technical details of what they discovered. And WeLiveSecurity also has a writeup on how the infection worked.
Botnets are a problem. Catching people is a long, drawn out challenge. But, it can be done.

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Anatomy of a successful phishing attempt

Earlier this year the Exploratorium was the victim of a phishing attack. They’ve posted an article on what happened and how they discovered and dealt with the issue.
But they didn’t just report on the attack, they dissected it. And, as is appropriate for a organization with a mission of education, they mapped out what they discovered during the investigation.

There are a couple of things that stand out to me about this attack. One is that of the more interesting pieces to me is that there was a delay between the compromise and the start of the attack. The Exploratorium calls it “the pivot” and describes it as the hacker deciding what to do next. The second is that the phisher actively interacted with the victim’s account. All new mail was sent to the trash automatically so she wouldn’t see incoming mail. Some mail was actively replied to so more people would click on the message. The phisher took steps to retain access to the account for as long as possible.
One thing that the Exploratorium didn’t see was any actual access to Exploratorium files or information. That may be because the Exploratorium itself wasn’t the target. Once a phisher / hacker has access to the email account, they have access to almost everything in your online life: calendars, bank accounts, credit accounts, the list goes on. Email addresses are our online identity and getting access to the address can open access to so much more.
Quite frankly it can happen to any of us. Earlier this week we received a phishing message that looked very plausible. It came from a law firm, mentioned a subpoena and even had an attachment personalized to our company. The attachment wasn’t opened so we were fine, but I can see how that kind of email might trick someone into getting infected.
We all need to be careful online. Email is a wonderful thing, but it’s insecure. It’s a great way for criminals to get into our space and wreck havoc on our computers and our lives.
 

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Are botnets really the spam problem?

Over the last few years I’ve been hearing some people claim that botnets are the real spam problem and that if you can find a sender then they’re not a problem. Much of this is said in the context of hating on Canada for passing a law that requires senders actually get permission before sending email.
Botnets are a problem online. They’re a problem in a lot of ways. They can be used for denial of service attacks. They can be used to mine bitcoins. They can be used to host viruses. They can be used to send spam. They are a problem and a lot of people spend a lot of time and money trying to take down botnets.
For the typical end user, though, botnets are a minor contributor to spam in the inbox. Major ISPs, throughout the world, have worked together to address botnets and minimize the spam traffic from them. Those actions have been effective and many users never see botnet spam in their inbox, either because it’s blocked during send or blocked during receipt.
Most of the spam end users have to deal with is coming from people who nominally follow CAN SPAM. They have a real address at the bottom of the email. They’re using real ISPs or ESPs. They have unsubscribe links. Probably some of the mail is going to opt-in recipients. This mail is tricky, and expensive, to block, so a lot more of it gets through.
Much of this mail is sent by companies using real ISP connections. Brian Krebs, who I’ve mentioned before, wrote an article about one hosting company who previously supported a number of legal spammers. This hosting company was making $150,000 a month by letting customers send CAN SPAM legal mail. But the mail was unwanted enough that AOL blocked all of the network IP space – not just the spammer space, but all the IP space.
It’s an easy decision to block botnet sources. The amount of real mail coming from botnet space is zero. It’s a much bigger and more difficult decision to block legitimate sources of emails because there’s so much garbage coming from nearby IPs. What AOL did is a last resort when it’s clear the ISP isn’t going to stop spam coming out from their space.
Botnets are a problem. But quasi legitimate spammers are a bigger problem for filter admins and end users. Quasi legitimate spammers tend to hide behind ISPs and innocent customers. Some send off shared pools at ESPs and hide their traffic in the midst of wanted mail. They’re a bigger problem because the mail is harder to filter. They are bigger problems because a small portion of their recipients actually do want their mail. They’re bigger problems because some ISPs take their money and look the other way.
Botnets are easy to block, which makes them a solved problem. Spam from fixed IPs is harder to deal with and a bigger problem for endusers and filters.

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Following the SMTP rules

An old blog post from 2013, that’s still relevant today.
“Blocked for Bot-like Behavior”
An ESP asked about this error message from Hotmail and what to do about it.
“Bot-like” behaviour usually means the sending server is doing something that bots also do. It’s not always that they’re spamming, often it’s a technical issue. But the technical problems make the sending server look like a bot, so the ISP is not taking any chances and they’re going to stop accepting mail from that server.
If you’re an ESP what should you look for when tracking down what the problem is?
First make sure your server isn’t infected with anything and that you’re not running an open relay or proxy. Second, make sure your customers aren’t compromised or have had their accounts hijacked.
Then start looking at your configuration.
HELO/EHLO values

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