Mostly blocked, but still good enough: Necurs sending pump-and-dump spam

Posted by   Martijn Grooten on   Mar 22, 2017

Over the past few days, the Necurs spam botnet has increased its activity, sending large amounts of pump-and-dump spam, in which a cheap stock is pushed with the aim of making a profit for those behind the campaign. The Dynamoo blog lists examples of the various emails sent, while Cisco's Talos group provides some context to Necurs' recent activity. 

Necurs isn't new: in 2014, Virus Bulletin published a series of articles on the malware by Microsoft researcher Peter Ferrie (1, 2, 3). In fact, Necurs, which used to spread through exploit kits, actually stopped spreading some time ago, meaning that the infections involved in the recent activity will have existed for a long time (thanks to MalwareTech for confirming this).

It therefore doesn't come as a surprise that most of the Necurs spam we see comes from countries like Vietnam, India and Indonesia, where for understandable economic reasons, computer hygiene isn't on par with that in more advanced economies.

necursspam.png

The spam itself isn't particularly advanced either, and no effort has been made to bypass spam filters. The emails don't use DKIM, and the MAIL FROM addresses don't appear to have been chosen with the aim of avoiding SPF fails. We looked at one Necurs spam campaign that started this morning and found that most of the spam filters we are currently testing in our lab blocked all of the messages; in fact, all but a handful of IP addresses from which the spam was sent were listed on prominent IP blacklists. It is thus fair to say that very few of the emails in this campaign would have been seen by a human being.

But maybe that doesn't matter for those who hired Necurs to send out the spam: all they would have cared about is that some people would act on the spam and buy the stock, thus increasing its value. Or maybe that trading algorithms scouring the Internet would notice an increase in mentions of the stock and buy it, thus increasing its value. Whatever the reason, the value of the stock did indeed rise

That doesn't mean that Necurs' clients don't have a reason to complain about the service provided: more than half of the Necurs spam we saw in this particular campaign was sent to email addresses with a made-up local-part, likely a method used by the botnet owners as an easy way to increase numbers. Things change quickly in the global threat landscape, but one thing remains the same: in 2017, you still can't trust spammers.

In the meantime, such campaigns provide interesting possibilities for malware researchers.

twitter.png
fb.png
linkedin.png
hackernews.png
reddit.png

 

Latest posts:

VB2018 paper: Internet balkanization: why are we raising borders online?

At VB2018 in Montreal, Ixia researcher Stefan Tanase presented a thought-provoking paper on the current state of the Internet and the worrying tendency towards raising borders and restricting the flow of information. Today we publish both his paper…

The malspam security products miss: banking and email phishing, Emotet and Bushaloader

The set-up of the VBSpam test lab gives us a unique insight into the kinds of emails that are more likely to bypass email filters. This week we look at the malspam that was missed: banking and email phishing, Emotet and Bushaloader.

VB2018 paper: Where have all the good hires gone?

The cybersecurity skills gap has been described as one of the biggest challenges facing IT leaders today. At VB2018 in Montreal, ESET's Lysa Myers outlined some of the things the industry can do to help address the problem. Today we publish Lysa's…

Preview: Nullcon 2019

We look forward the Nullcon 2019 conference in Goa, India, at which VB Editor Martijn Grooten will give a talk on the state of malware.

From Amazon to Emotet: a look at those phishing and malware emails that bypassed email security products

We see a lot of spam in the VBSpam test lab, and we also see how well such emails are being blocked by email security products. Recently some of the emails that bypassed security products included a broken Amazon phishing campaign, a large fake UPS…

We have placed cookies on your device in order to improve the functionality of this site, as outlined in our cookies policy. However, you may delete and block all cookies from this site and your use of the site will be unaffected. By continuing to browse this site, you are agreeing to Virus Bulletin's use of data as outlined in our privacy policy.