Category Archives: Ransomware

Managed ‘Russian ransomware’ as a service spotted in the wild

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By Dancho Danchev

In 2013, you no longer need to posses sophisticated programming skills to manage a ransomware botnet, potentially tricking tens of thousands of gullible users, per day, into initiating a micro-payment to pay the ransom for having their PC locked down. You’ve got managed ransomware services doing it for you.

In this post I’ll profile a recently spotted underground market proposition detailing the success story of a ransomware botnet master that’s been in business for over 4 years, claiming to be earning over five hundred thousands rubles per month.

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Webroot’s Threat Blog Most Popular Posts for 2012

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By Dancho Danchev

It’s that time of the year! The moment when we look back, and reflect on Webroot’s Threat Blog most popular content for 2012.

Which are this year’s most popular posts? What distinguished them from the rest of the analyses published on a daily basis, throughout the entire year?

Let’s find out.

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How malware authors evade antivirus detection

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By Dancho Danchev

Aiming to ensure that their malware doesn’t end up in the hands of vendors and researchers, cybercriminals are actively experimenting with different quality assurance processes whose objective is to increase the probability of their campaigns successfully propagating in the wild without detection.

Some of these techniques include multiple offline antivirus scanning interfaces offering the cybercriminal a guarantee that their malicious program would remain undetected, before they launch their malicious campaign in the wild.

In the wild since 2006, Kim’s Multiple Antivirus Scanner is still actively used among cybercriminals wanting to ensure that their malicious software is pre-scanned against the signature-based scanning techniques offered by multile antivirus vendors.

Let’s review Kim’s Multiple Antivirus Scanner, and discuss when it’s an important tool in the arsenal of the malicious cybercriminal spreading malware for profit.

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Criminals Abuse Amazon Hosting with Rogues, Ransomware

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By Andrew Brandt

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The criminals who push rogues at the world don’t really care about the reputations of the ISPs or Web hosting services they abuse. They leap from free service to free service until they’ve thoroughly worn out their welcome and, in some cases, destroyed the reputation of the service they abused. But they have behaved in one predictable way over the years: They’re stingy, and won’t pay for anything unless it’s absolutely necessary, despite the fact that they’re raking in cash by the boatload.

But that seemed to change this week when we saw a number of Web sites pop up on the radar. The sites employ the now well-worn scam of pretending to be some sort of video streaming service. In this case, they pretended to be a porn site, but the most surprising part was not what was hosted, but where: Amazon’s Cloudfront hosting service ended up, temporarily for a few hours, serving up malicious Web pages. Amazingly, it seems they actually paid for hosting instead of just stealing it.

Amazon shut the sites down quickly, but before they did, we visited one site called xrvid-porno.com. The page isn’t exactly family friendly, but the gist of the scam is that that page eventually redirected the browser to a server inside of Amazon’s cloud hosting service, and that’s where the trouble began.

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Removing Popureb Doesn’t Require a Windows Reinstall

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By Marco Giuliani

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Last Wednesday, Microsoft published a blog post detailing a significant update to a piece of malware named Popureb. The malware adds code to the Master Boot Record, or MBR, a region of the hard disk that’s read by the PC during bootup, long before the operating system has had a chance to get started. Researchers sometimes refer to these kinds of malware as bootkits, or a rootkit which loads at such a low level during the boot process that it is invisible to the operating system, and therefore very difficult to remove.

Microsoft researcher Chun Feng detailed some of the new features of Popureb.E, which includes a very low-level hook into the Windows driver responsible for disk writes and reads. When the driver on an infected system detects an attempt to write changes into the MBR — the kinds of changes a repair tool might try to make — it simply changes the command from write to read, effectively neutering any kind of tool running within Windows that might try to fix the infection.

(Update 2011-07-08: We’ve published a free command line tool that can remove Popureb.E from the master boot record of an infected computer.)

Microsoft’s initial cleanup guidance on Popureb.E was pretty drastic, and more than a little scary: Full removal of the bootkit requires a full reinstall of Windows, wiping out anything currently on the hard drive. We don’t think this is the case, and the Microsoft folks seem to have moderated their advice to include some manual fixes using the recovery console.

While the whole concept behind the Trojan is valid and technically powerful, the practical implementation of the malware is not as valid as the idea behind it. What follows is a fairly technical write-up that describes both the problem, and one  solution we’ve come up with.

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New Rogue Is Actually Five Rogues in One

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By Andrew Brandt

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For years, the makers of those snake oil security programs we call Rogue Security Products have spent considerable effort making up new names, developing unique graphic design standards, and inventing backstories for their utterly useless, expensive scam products. Now a new rogue has taken this never ending shell game one step further, releasing a single program that calls itself one of five different names, depending on what button an unfortunate victim clicks in a highly deceptive dialog box. Let’s call it what it really is, though: A malicious play in five acts.

The rogue’s delivery method, or Act 1 in this melodrama, is no different from the many we’ve seen in the past 18 months which use a Javascript-enhanced Web page to convince viewers they’re watching a live malware scan on their computer. This trick is so hackneyed, it’s become the cybercrime equivalent of the dastardly villain in a silent movie tying the hapless woman to a railroad track, then twisting the ends of his mustache for dramatic effect. Does anyone still fall for this?

Only, this time the fakealert delivers a different payload: When the victim runs the rogue executable (named simply setup.exe), Act 2 begins. The rogue displays a dialog box that looks like an alert message issued by Microsoft Security Essentials, cautioning the victim that a legitimate Windows component present on most or all installations of Windows, such as iexplore.exe or cmd.exe, is actually a piece of malware.

The rogue helpfully offers to perform some sort of online scan, and that’s where it gets weird. The rogue pretends to scan the hard drive with 32 different antivirus engines, a-la VirusTotal. The vast majority of them are well known, at least in the security community. But five are new, and it’s those five that merit closer inspection.

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Ransomware App Asks Victims to Pay a Phone Bill

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By Andrew Brandt

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Ransomware is nothing new, but a Ukrainian ransomware Trojan that came over the transom last week demonstrated that the concept of “payment” can extend to services other than banking or finance. In this case, the Trojan (which we and several other AV companies call Trojan-Ransom-Krotten) thoroughly locks down the infected system then demands payment—in the form of credit paid to the Ukrainian mobile phone provider Kyivstar, which the victim then has to transfer to the malware distributor’s account.

Yes, Alice, the hacker wants you to pay his cellphone bill.

Once the ransomware has taken hold on a victim’s computer, it locks down the operating system in dozens of different ways, as well as changing several registry keys that add juvenile, profane text to Internet Explorer’s title bar and elsewhere on the desktop and in folders.

Paying the ransom in these cases simply emboldens the malware creator to continue his crime spree. Of course, even once a victim hypothetically pays this ransom, there’s also no guarantee that there’s any way at all for the malware distributor to reverse the damage — which takes the form of significant levels of annoyance — caused by this insipid Trojan.

Fortunately for the victim, the creator of this Trojan isn’t the sharpest tack in the box. Not only were we easily able to tease out the Trojan’s payloads and add signatures which would prevent the Trojan from delivering its payload files to a victim’s computer, but we’re able to see exactly how the author (ineffectively) tries to frustrate the kinds of behavioral analysis we and other antivirus vendors perform.

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