Captchabot: Blurring Human and Machine

November 16, 2010

Last week, I wrote about a “bulletproof hosting” provider that offers dodgy Web hosting that is insulated from takedown by abuse complaints or requests from Western law enforcement agencies. Today, I’ll look at one of that bulletproof provider’s biggest clients: Captchabot.com, a service that automates the solving of “CAPTCHAs,” those annoying agglomerations of squiggly numbers and letters that many online services require users to solve to help ensure that new accounts are not being auto-created by a computer.

These so-called reverse Turing Tests can be exasperating for legitimate users, but these days they are little more than a speed bump for those who specialize in mass-creating bogus new accounts at popular online destinations like Facebook, MySpace, YouTube for use in spreading spyware and pimping spammy Web sites.

That’s thanks largely to services like Captchabot, which automate the solving of CAPTCHAs with the help of low-paid workers in China, India and Eastern Europe who earn pennies per hour deciphering the puzzles.

Captchabot charges clients based on how many thousand CAPTCHAs they ask the service solve: $1 buys about 1,000 solved CAPTCHAs. The service claims at least an 80 percent success rate, and customers only pay for CAPTCHAs that are solved correctly.

In their seminal paper (PDF) on CAPTCHA-solving services, researchers at UC San Diego earlier this year tried to estimate how many employees it would take to solve the daily workload of CAPTCHAs fed to the various services. The researchers guessed that Captchabot.com would need to have between 130 and 200 workers available more or less around the clock (for a look at how these services performed against CAPTCHAs required by MySpace, Google, Wikipedia and others, see this graphic.)

The researchers also sought to learn where most of the puzzle-solving workers resided, so they fed Captchabot and other services a variety of CAPTCHAs from different languages. The results, shown in the screen shot here, indicated that most of the workers were Chinese, English and Russian speakers.

I contacted the owner of Captchabot.com, a hacker named Mirko Res, via online chat to see if I could fine-tune the UCSD estimates on the number of workers employed by the service, but he was unwilling to give an exact figure (“under NDA,” he explained). He did say, however, that the majority of the workers employed by his service live in Belarus, and that workers are only passed puzzles that can’t be solved by the service’s automated CAPTCHA-guessing algorithm.

“They using it for legal Webspam, like blog comments,” Res said of his operation’s customers. In fact, a widely-used forum- and blog-spamming tool known as XRumer relies exclusively on Captchabot to deliver its CAPTCHA-cracking capability.

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OS X Patch Catch-Up

November 15, 2010

Apple recently released a massive update to address at least 130 security vulnerabilities in Mac OS X systems, including a monster patch that fixes 55 flaws in Adobe Flash Player.

The seventh major update to OS X  this year includes a fix that stems from a vulnerability Apple patched in the iPhone earlier this year but apparently never scrubbed on OS X. According to security vendor Core Security — which said it released details about the flaw ahead of Apple’s advisory after waiting nearly three months for Apple to fix it — the vulnerability is a variation of the flaw exposed this summer that helped iPhone users jailbreak devices running iOS4. Apple fixed that bug in the iPhone shortly after the exploit was released, but until last week the flaw remained a weak spot in OS X 10.5/Leopard systems, Core said.

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Pursuing Koobface and ‘Partnerka’

November 12, 2010

In any given week, I read at least a dozen reports and studies, but I seldom write about them because their conclusions either are obvious or appear slanted toward generating demand for specific products and services. Occasionally, though, a report will come along that is so full of useful data — and resonates so loudly with some of my own investigations — that it forces me to reassess my immediate research and reporting priorities.

One report released today that falls squarely into the latter category is Nart Villeneuve‘s superbly researched and detailed analysis (PDF) of “Koobface,” a huge network of hacked computers that are compromised mostly by social engineering scams spread among users of Facebook.com (Koobface is an anagram of “Facebook”). As the report describes, the Koobface infrastructure is a crime machine fed by cyber criminal gangs tied to a variety of moneymaking schemes involving Web browser search hijacking and the installation of rogue anti-virus software.

This report traces the trail of Koobface activity back through payments made to top criminal partners — known as Partnerka (PDF) — a mix of private and semi-public affiliate groups that form to facilitate coordinated malware propagation.

From the report:

“The Koobface operators maintain a server known as the mothership [which] acts as an intermediary between the pay-per-click and rogue security software affiliates and the compromised victims. This server receives intercepted search queries from victims’ computers and relays this information to Koobface’s pay-per-click affiliates. The affiliates then provide advertisements that are sent to the user. When a user attempts to click on the search results, they are sent to one of the provided advertisement links instead of the intended location. In addition, Koobface will receive and display URLs to rogue security software landing pages or will directly push rogue security software binaries to compromised computers. As a result, Koobface operators were able to generate over two million dollars in a one-year period.”

The report lists the nicknames of top Koobface affiliates, showing the earnings for each over the past year and the Web addresses of their associated affiliate programs. This is the kind of intelligence that — if shared broadly — has the potential to massively disrupt large scale criminal operations, because cybercrime researchers can use it to make sense of seemingly disparate pieces of information about criminal actors and groups. Nevertheless, it is rare to see this kind of raw data published, at least while those implicated remain at large.

Part 3 of the report, titled “The Takedown,” indicates that operations to shutter the Koobface infrastructure may already be underway. Earlier this year, McAfee published an analysis I wrote about takedowns that classified them into two groups: “Shuns” — which seek to shame the peers of a malicious network into severing its connections — and “stuns,” which refer to efforts to disconnect the physical and network control infrastructure used by a botnet. According to the report’s authors, a stun against Koobface is in the works.

“Prior to the publication of this report, notifications were delivered to the owners of the infrastructure that Koobface is abusing,” Villeneuve writes. “They include: fraudulent and stolen Facebook and Google accounts, stolen FTP credentials, and dedicated command and control servers. We are working to synchronize notification to the operators of these elements in order to have an impact on the operations of the Koobface botnet.”

Almost certainly more to come soon. Stay tuned.

Gelezyaka.biz, one of the rogue anti-virus affiliate programs tied to Koobface

Charting the Carnage from eBanking Fraud II

November 12, 2010

Several readers have asked to be notified if the U.S. map showing recent victims of high-dollar online banking thefts was updated. Below is a (non-interactive) screen shot of the updated, interactive map that lives here. Click the red markers to see more detail about the victim at that location, including a link to a story about the attack.

All-in-One Skimmers

November 10, 2010

ATM skimmers come in all shapes and sizes, and most include several components — such as a tiny spy cam hidden in a brochure rack, or fraudulent PIN pad overlay.  The problem from the thief’s perspective is that the more components included in the skimmer kit, the greater the chance that he will get busted attaching or removing the devices from ATMs.

Thus, the appeal of the all-in-one ATM skimmer: It stores card data using an integrated magnetic stripe reader, and it has a built-in hidden camera designed to record the PIN sequence after an unsuspecting customer slides his bank card into the compromised machine.

The model displayed here is designed to work on specific Diebold ATMs, and can hold a battery charge for two to four days, depending on ambient temperature and the number of customers who pull money out of the hacked ATM.

Functionally, it is quite similar to the all-in-one model pictured in the very first skimmer post in this ATM skimmer series, although its design indicates it may be identical to the one pictured here, which was found on a Wachovia ATM just a couple of miles from my home earlier this year.

The tiny pinhole camera in the image above is angled so that it points at the PIN pad below and to the left, recording the victim’s 4-digit personal identification number to a flash-based memory card.

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Microsoft Plugs Office Holes, But No IE Fix Yet

November 9, 2010

Microsoft Corp. today issued three bundles of updates fixing at least 11 security vulnerabilities in its software, mainly flaws in Microsoft Office products. But the company did not release an update today to remedy  a critical flaw built into in all versions of the Internet Explorer Web browser that is now being exploited by at least one common, automated hacker toolkit.

Two of the updates address Office bugs, including one that is limited to older versions of PowerPoint and PowerPoint Viewer. Only one of today’s patches earned a “critical” rating, Microsoft’s most serious. But experts are warning that this critical Office vulnerability is likely to be used in targeted e-mail attacks against Microsoft Outlook users.

“One of the most dangerous aspects of this vulnerability is that a user doesn’t have to open a malicious email to be infected,” said Joshua Talbot, security intelligence manager for Symantec Security Response. “All that is required is for the content of the email to appear in Outlook’s Reading Pane. If a user highlights a malicious email to preview it in the Reading Pane, their machine is immediately infected. The same holds true if a user opens Outlook and a malicious email is the most recently received in their inbox; that email will appear in the Reading Pane by default and the computer will be infected.”

Microsoft did not issue an update to fix a zero-day flaw in Internet Explorer that bad guys are exploiting to break into Windows computers. Last week, the software giant warned that crooks were exploiting the flaw in targeted attacks, and that it had no intention of issuing a fix for the security hole outside of its normal monthly patching process (the second Tuesday of each month — today — is Patch Tuesday).

Since that advisory, the IE exploit has been bundled into the Eleonore Exploit pack, a powerful and widely-used commercial crimeware kit that makes it trivial for attackers to turn legitimate Web sites into platforms for installing malware when visitors browse the sites with vulnerable PCs.

If you have Office Installed, take a moment to visit Microsoft Update to patch things up. If you use IE, either upgrade to IE8 — which provides additional protections against this zero-day attack — or consider implementing the Fix-It tool that Microsoft has released to help mitigate the threat from the vulnerability.

A summary of today’s bulletins is available here.

Update, 7:03 p.m. ET: Added information at the end of this post on the Microsoft FixIt Tool.

Body Armor for Bad Web Sites

November 9, 2010

Hacked and malicious sites designed to steal data from unsuspecting users via malware and phishing are a dime a dozen, often located in the United States, and are a key target for takedown by ISPs and security researchers. But when online miscreants seek stability in their Web projects, they often turn to so-called “bulletproof hosting” providers, mini-ISPs that specialize in offering services that are largely immune from takedown requests and pressure from Western law enforcement agencies.

Until recently, you more or less had gain access to and lurk on the right underground forums to be able to rent services from bulletproof hosting providers. These days, it’s becoming easier to find these badware havens advertising out in the open. Last week, I traced the activities of one particular service frequented by criminals back to a bulletproof provider whose slogan says it all: “You’ll Never Get Any Abuse From Us!

Of course, just how insulated this particular provider’s services are and how much illicit activity you can get away with while using them depends largely on how much you’re willing to shell out each month. For example, an entry level “default bulletproof server” allows customers to host things like rogue online pharmacies, replica, gambling, and MP3 sites for $270 per month. But this service level bars customers from hosting nastier content, such as malware, spyware, adware, exploits, viruses, and phishing sites.

Upgrade to the “Super BulletProof Virtual Dedicated Servers in China” — and pay almost $500 a month — and the only activities that are prohibited are sending spam and hosting any type of porn.

The provider pictured here also upsells potential customers by offering a variety of handy add-on services. For extra coin each month, one can rent a bulletproof server with a license for XRumer, a black hat search engine manipulation tool that automates the registration of new Web forum accounts and the spamming of links on those forums, all in a bid to boost the search engine rankings of the spamvertized site. If you operate a blog and have had to deal with what appear to be automated, link-filled comments, chances are good that XRumer was involved in some way.

For a $20 one-time setup fee, your server will come pre-packaged with links for forums that XRumer is able to spam, including thousands of Web pages in top-level domains that are often given more ranking weight by search engines, such as .edu, .gov and .mil.

[EPSB]

Have you seen:

Earn a Diploma from Scam U…Since the dawn of the Internet, tutorials showing would-be scammers how to fleece others have been available online. But for novices who can’t be bothered to scour the Net for these far flung but free resources, the tricks of the trade now can be learned through the equivalent of community college classes in e-thievery, or or via intensive, one-on-one online apprenticeships.

[/EPSB]

Authorities Nab More ZeuS-Related Money Mules

November 8, 2010

Authorities in the United States and Moldova apprehended at least eight individuals alleged to have helped launder cash for an international cyber crime gang that stole more than $70 million from small to mid-sized organizations in recent months.

In Wisconsin, police arrested two young men who were wanted as part of a crackdown in late September on money mules who were in the United States on J1 student visas. The men, both 21 years old, are thought to have helped transfer money overseas that was stolen from U.S. organizations with the help of malicious software planted by attackers in Eastern Europe.

Codreanu and Adam

Dorin Codreanu and Lilian Adam, both originally from Moldova, are being transferred to New York, where they were charged on Sept. 30 in connection with the international money laundering scheme (hat tip to Sophos).

In related news, the government of Moldova’s Specialized Services Center for Combating Economic Crimes and Corruption (CCECC) announced late last month that it had detained six individuals suspected of helping the same international ZeuS gang launder money.

All six of those detained were bank employees, and one worked at the Bank of Moldova. According to Moldovan authorities, the suspects allegedly specialized in intercepting Western Union and MoneyGram payments that mules had sent to Eastern Europe after receiving bank transfers from organizations victimized by the ZeuS Trojan.

Altogether, Moldovan prosecutors are looking at 12 suspects, including a government official who is alleged to have provided the group with copies of ID cards needed to open bank accounts. That nation’s anti-corruption center said it has conducted over 30 searches at detainees’ houses, and seized at least $300,000, a gun, and two luxury cars.

Eleven of the 37 money mules charged in September in connection with these attacks are still at large. Photos of the suspects are available at this alert posted by the FBI.

Keeping an Eye on the SpyEye Trojan

November 8, 2010

Last month, I published evidence suggesting that future development of the ZeuS banking Trojan was being merged with that of the up-and-coming SpyEye Trojan. Since then, a flood of new research has been published about SpyEye, including a new Web site that helps track the location of SpyEye control networks worldwide.

Roman Hüssy, the curator of Zeustracker — a site that has spotlighted ZeuS activity around the globe since early 2009 — late last week launched SpyEye Tracker, a sister service designed to help Internet service providers keep tabs on miscreants using SpyEye (take care with the IP address links listed at this service, because they can lead to live, malicious files).

Hüssy said he’s not convinced that the SpyEye crimeware kit will usurp the mighty ZeuS. “Why should they give up something which works and pay for a new tool?” he said in an online chat with KrebsOnSecurity.com. Instead, Hüssy said he’s launching the new tracking service to help prevent that shift.

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Flash Update Plugs 18 Security Holes

November 5, 2010

Adobe on Thursday released an update to its Flash Player software that fixes at least 18 security vulnerabilities, including one that is being exploited in targeted attacks.

The Flash update brings the latest version to v 10.1.102.64. To find out if your computer has Flash installed (it almost certainly does) and what version it may be running, go here. The new version is available from this link, but be aware that if you accept all of the default settings, the update may include additional software, such as a toolbar or anti-virus scanner.

If you’d like to avoid Adobe’s obnoxious Download Manager and all these extras, grab the update from this link instead. Updates are available for Windows, Macintosh, Linux, and Solaris versions of Flash.

If you use Internet Explorer in addition to other browsers, you will need to apply this update twice: Once to install the Flash Active X plugin for IE, and again to update other browsers, such as Firefox or Google Chrome (you may find that Google has already updated their browser with this fix). Also, while it’s not strictly necessary, Adobe recommends that users uninstall the previous version of Flash before updating to the latest copy of Flash. Instructions and tools for removing Flash are here.

More information on the vulnerabilities fixed in this patch is available in the Adobe advisory.