Category Archives: adware

Software designed either to (1) display ads to the computer user, or (2) load ad pages in the background, using the victim’s resources to do so. (see also: clickfraud)

Chinese Trojan Turns Infected PCs Into Web Servers

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By Andrew Brandt

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A complex and elaborately conceived family of malware that originates in China installs the Apache Web server, as well as half a dozen keylogger and downloader payloads, disguised as components of legitimate apps. We and a few other antivirus vendors are calling this type of malware Taobatuo.

It just so happens that I’ve been setting up a Windows virtual machine with the latest versions of Apache, MySQL, and PHP for an unrelated project. I hadn’t installed these apps onto a Windows box before, and Apache in particular is notoriously finicky about Windows installations, so after several days of trial and error (mostly error) I was somewhat amused to discover, after finally getting Apache to work, that the malware sample I tested actually pulls down its own working, customized Apache installer…along with a bunch of phishing Trojans, keyloggers, and downloaders, all dressed up to look like the services you might see on a Microsoft-based Web server.

It just goes to show how much good these malware creators could accomplish, simply if they wanted to. But that’s clearly not the goal. The malware, along with text files containing instructions for the malware, came from taobao.lylwc.com. That’s not to be confused with Taobao.com, one of China’s most heavily trafficked Internet portals. This site and the real Taobao are not related in any way I can determine, other than the (ab)use of the Taobao name.

The lylwc.com domain itself is quite a piece of work. It claims to offer free downloads or streams of current Hollywood movies, as well as an extensive library of films and TV shows. The operative word is “claims” — when you try to view those movies, the site attempts to push a download of a Trojaned installer for the QVOD media player (a streaming media app that’s popular in China). So let’s just say I wasn’t all that surprised to find the taobao subdomain of this Web site hosting a raft of malware.

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Five Reasons You Should Always “Stop. Think. Connect.”

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By Andrew Brandt

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Today’s the official kickoff for National Cyber Security Awareness Month, and the organizations supporting the event, including the National Cyber Security Alliance, the Anti-Phishing Working Group, and dozens of corporate citizens including Webroot, want you to protect your computer and your personal information. So they’ve come up with a three word campaign slogan they hope will become conventional wisdom for every Internet user: Stop. Think. Connect. Think of it as the 21st century equivalent of looking both ways before crossing the street.

In my case, they’re preaching to the choir. For years, I’ve advocated that people treat everything they see online critically, and to scrutinize information before acting on it. That’s because the army of criminals who commit fraud and theft over the Internet on a daily basis rely on you to not stop, not think, and to click links or open files immediately, without regard to the consequences of your actions. That’s how most people infect themselves. If you stop and think before you connect, you can prevent most of these infections yourself, simply by exercising a little restraint.

It’s hard to think of a major cybercrime outbreak over the past year that hasn’t relied, to some extent, on the naivete of its targets. Security professionals call these tricks “social engineering,” but that’s just a geeky term for criminal skullduggery that’s as common offline as online. The ruse almost always tries to invoke an adrenaline-fueled need for an immediate response — usually out of fear, greed, or panic — on the part of a victim. The victim ends up in a mental state where they are likely to make rash, impulsive decisions. And they do.

Putting the brakes on social engineering tricks usually takes all the steam out of them. To that end, I’d like to show you examples of five of the most common cyberscams that lead to the loss of personal information or sensitive data. Hopefully, if you know what to expect, you’ll simply walk away from the encounters unscathed.

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Newsflash: HTML Spammers are Not So Bright

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By Andrew Brandt

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It’s been more than a week that we at Webroot, and countless others, have been getting floods of bogus messages with HTML attachments. I thought I’d give the curious readers of this blog a quick glance at one of the drive-by sites that load in the browser if you try to open the file.

As I’d mentioned previously, the HTML files themselves simply contain highly obfuscated Javascript (code that’s hard for humans to read but easy for machines to interpret). When you try to load those malicious scripts into a browser, the script instructs the browser to load a page from another Web site. In fact, the file I saw today goes to server 1, which bounces the browser to server 2, and then a script on server 2 loads more files from servers 3 & 4 in a full-screen iFrame.

In the end, what I saw looked like an update to what has become the “classic” Javascript fakealert. Unfortunately for the malware distributors, this so-called update is laughably obvious. These are clearly not the sharpest tacks in the box.

It all starts with a warning popup which reads:

There is a big chance that your computer is infected! They can cause data loss and file  damages and need to be fixed as soon as possible. Return to Microsoft Security Assessment Tool and download it to   guard your PC.

Wow, really? How big is the chance? Is this more like a scratch-off lottery ticket level of chance, or is it closer to a look under the bottle cap to see if you win chance? What they don’t tell you is that your chance of becoming infected with an annoying rogue increases to about 100% if you continue down this well-worn path. Continue reading →

Epic Malware Dropper Makes No Attempt to Hide

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By Andrew Brandt

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In the world of first-person shooter games, getting the most headshots – hits on the opponent which instantly take the opponent’s avatar out of the game — is a prized goal. The headshot is the quickest way to dispatch a foe in virtually every shooter, which is why the file name of a malware sample, currently in circulation, stood out.

The file, yogetheadshot.php.exe (VT), is a dropper, a glorified bucket designed to tip over and spill other malware all over a PC. But where other droppers might leave behind a handful of payloads, this one utterly decimated a testbed PC with a malware headshot — an unusually overt infection that, defying conventional wisdom about malware infections, took no apparent effort to mask its behavior or remain low key.

The file, extracted from network traffic recorded while a test system got manhandled by a drive-by download site, was only one of several executable payloads that originated from the same domain hosting the drive-by.

But this sole dropper was more than capable of delivering the terminal blow to a middle aged Windows XP box. We first saw it appear on September 7th, but it has become more widespread since then.

(Update, 22 Sept.: Here’s a video that shows what happens on a system when someone executes this dropper. The dropper is near the upper-left corner of the screen. The rest of the screen is taken up with Process Explorer, which lets you see just how many payloads the dropper delivers.)

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Blog Comment Spam Points to Drive-By Site

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By Andrew Brandt

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I just want to take a moment to thank the malware author who posted a spam comment to the Webroot Threat Blog blog the other day. You guys make my job so easy.

The spam comment, which reads Hello. I the beginner. I wish to show to you,scandal story and links to a drive-by download site, is a tremendous help to our researchers, who are always on the lookout for new threats.

Of course, the malware distributor could have employed a more effective hook to convince someone to click a link than the one he used.

The link claims to point to a page hosted on the free Blogspot blog site to a nude video — not of Paris Hilton, Venus Williams, or Erin Andrews — but of…Diane Sawyer, the respected, award-winning anchor of ABC’s World News Tonight.

“Diane Sawyer Nude” — seriously? News anchor porn? Whatever happened to malware authors touting nude photos of starlets as an enticement?
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Modified Websites Pushing Trojans On the Rise

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By Andrew Brandt

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For the past couple of weeks, owners of Web sites have been hit with a wave of attacks that surreptitiously infect unsuspecting visitors with a wide variety of malware types. The first wave inflicted rogue antivirus on unlucky victims, but late last week victims who visited infectious sites were redirected into a drive-by download site that pushes clickers onto a vulnerable visitor’s computer.

The affected web sites have been modified to add malicious, obfuscated Javascript code to the footer of each page. Some Web hosts are trying to notify customers or fix the problems. At first, the problem affected sites that run the open-source WordPress publishing system, but the attack has broadened into non-Wordpress (and non-blog) Web sites. The gobbledygook Javascript opens an iframe hosted from a different Web site, and the code that loads inside that iframe redirects the victim’s browser to yet another site, which loads the infection and executes it.

I’m going to name (domain) names in this post, so please, for your own sake, use this information only to block the domains at your gateway or in your Hosts file — don’t go visiting them just to see what happens. I guarantee you won’t like what happens.

In the earlier attacks that began the week of April 5th, the malicious script directed victims to a page hosting the Eleonor exploit kit; The kit uses several well-worn methods to try to push executable malware (typically the Tacticlol downloader, which malware distributors have been using of late to push down rogue antivirus programs) at susceptible browsers, or computers running vulnerable versions of Adobe Acrobat or the Java Runtime Engine.

Those attacks originated from several domains, including corpadsinc.com, mainnetsoll.com, and networkads.net — all of which are hosted on the same IP address in Turkey, and are still live and hosting the exploit page.

But last week the script began directing users into a page on the domain name yahoo-statistic.com, a site which, despite its name, has nothing at all to do with the giant portal. That page, which loads in an iframe, opens other malicious sites which push the infection.

The list of affected sites is global, including a newspaper in Florida; the English-language page of a government’s Ministry of Women’s Affairs Web site; the Web site of a Spanish lawyer’s association; and a car dealership Web site in Indonesia. And as of today, visitors to this growing list of Web sites are still getting hit with Trojans.

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Fakealerts: Building a Better Mousetrap

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By Andrew Brandt

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In general, the use of fakealerts – those bogus warnings that look like your PC has started some sort of antivirus scan on its own, then predict imminent doom if you don’t buy some snake oil product right this minute — is on the rise. Fakealerts constitute a particularly effective social engineering trick, earning the makers of bogus, ineffective “antivirus” programs millions of dollars (and the scorn of victims) in the process. So it should come as no surprise that the fakealerts themselves have gone through some technological advances in the past year.

In the past few months, the fakealert-makers have slowly been migrating their techniques to a new platform: The browser. As recently as six months ago, the majority of fakealerts we saw were generated by small Trojan Horse applications running on a victim’s PC. Today, most fakealerts we see simply reshape the browser to mimic the appearance of a generic antivirus application.

It makes good economic sense for the creators of fakealerts to do this. The Windows application fakealerts only run on Windows (obviously). Like all Windows software, fakealert apps subject to being blocked by both the operating system (which, like the fakealerts themselves, prompts users with warnings in dialog boxes), by real-time detection mechanisms in legitimate antivirus software, and/or by savvy users themselves.

One typical load-sequence for the components of a scripted fakealert

Using a scripting technology such as Javascript to reproduce the “fakealert experience” is a natural extension of the success of fraudulent, rogue antivirus products. After all, a fakealert is no more than an elaborate performance for the targeted victim — the goal of the fakealert is simply to convince the victim to download and run a file, typically a rogue antivirus product. Javascript can run in virtually every browser and operating system (save for special cases, like the Firefox browser with the NoScript Add-On installed).

Scripts such as these bypass most traditional malware protection because, in essence, there is no malware installed until the victim installs it his- or herself. Unlike a static binary executable, the contents of a script can be tweaked, on the fly, to maximize effectiveness (or just to change the name of the fraudulent product). And the scripts themselves which make up the Web fakealert experience are highly obfuscated, which makes them more challenging for automated systems to block.

In the course of researching a new malware sample unrelated to fakealerts — an installer of Trojan-Downloader-Dermo on a page purportedly offering an update to Windows Media Player — I observed one common fakealert script as it ran soon after the testbed PC was infected. I was able to reconstruct its modus operandi.

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Rogues Mug Big Bird on his Birthday

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By Andrew Brandt

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20091104_picapp_BB_cropIn a move sure to raise the ire of Sesame Street fans everywhere, the black hat SEO gangs that have been manipulating Google results for the better part of the year have seized on a new target from which they’ve launched their current salvo of rogue antivirus guano. That’s right, the lovable, giant jaundiced avian friend to child and adult alike is being used to hijack searches and rope unsuspecting users into a vortex of popups and fake scans.

They have besmirched Big Bird. And on his birthday, of all days. Have the rogue AV purveyors no shame?

20091104_BB_volcanic_cropActually, they’ve just once again demonstrated that they, too, can take advantage of Google Trends, which rates the ‘hotness’ of searches for “Big Bird’s Birthday” today as “Volcanic.” It’s not surprising, really. Big Bird’s legs replaced the “L” in the Google logo this morning (in honor of the 40th anniversary of the popular character’s first Sesame Street appearance). So of course, people are clicking away at those feathered gams, trying to find out why they’re there.

The fake alerts touting the equally fake Internet Antivirus Pro warns users, through a series of browser popup alerts, that (like a fine strip of beef destined for the jerky factory) “your computer…need to be cured as soon as possible.”

The same advice we’ve given in the past prevails. Parents, also take note that you shouldn’t necessarily click — or let your kid(s) click — any old link that purports to lead to something child-friendly. The first link we saw appeared as the seventh search result on the first page of Google results. Many more appeared lower down. The text beneath the malicious result link read, in part, “Make your child s big day extra special with a personalized birthday banner!”

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Trojan Decodes Captchas Using Stolen Commercial Tools

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By Andrew Brandt

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20091002_lanci_captchas_cropA new Trojan quietly circulating in the wild uses components from a commercial optical character recognition (OCR) application to decode captchas, those jumbled-text images meant to help a website discern human activity from automated bots.

The OCR-using captcha breaking tool is just one component of the Trojan. Its main purpose appears to be to fill out contest entries, online polls, and other forms relating to marketing campaigns originating in the US, and it uses the OCR-cracking software in order to read the captchas and submit the form entries, on pages where the website presents a captcha to the user.

And this is not just any captcha-cracka, but a Swiss Army Knife of sorts. The maker of the “Advanced Captcha Recognition Engine” tool, based in China, claims that the tool is capable of bypassing more than 30 different captcha systems, including those used by Yahoo, MSN, and some of the largest portal sites and banks in China.

20091002_lanci_tocrprop_cropThe captcha decoding tool itself is a kludge, marrying some bespoke files and components expropriated from an older version of a commercial optical character recognition (OCR) suite called TOCR. The UK-based company that makes the TOCR software, Transym Computer Services, also licenses its components to third parties, though it’s not clear they knowingly have a relationship with the Chinese captcha cracker maker, nor were they aware that parts of their engine was repurposed for sale to Chinese malfeasants. The files appear to have been stolen or pirated, and used without Transym’s knowledge.

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