Krebs on Security

Where Did That Scammer Get Your Email Address?

April 25, 2011

You’ve seen the emails: They claim to have been sent by a financial institution in a faraway land, or from a corrupt bureaucrat in an equally corrupt government. Whatever the ruse, the senders always claim to need your help in spiriting away millions of dollars. These schemes, known as “419,” “advance fee” and “Nigerian letter” scams seemingly have been around forever and are surprisingly effective at duping people. But where in the world do these scammers get their distribution lists, and how did you become a target?

Some of the more prolific spammers rely on bots that crawl millions of Web sites and “scrape” addresses from pages. Others turn to sellers on underground cybercrime forums. Additionally, there are a handful of open-air markets where lists of emails are sold by the millions. If you buy in bulk, you can expect to pay about a penny per 1,000 addresses.

One long-running, open-air bazaar for email addresses is LeadsAndMails.com, which also goes by the name BuyEmails.org. This enterprise is based in New Delhi, India, and advertises its email lists as “100% opt-in and 100 percent legal to use.” I can’t vouch for the company’s claims, but one thing seems clear: Many of its clients are from Nigeria, and many are fraudsters.

Stretching conspicuously across the middle of the site’s home page is a big green message to the site’s Nigerian clientele: “Don’t waste money/times/resources sending [Western Union or Moneygram], Use local deposit option.” The ad links to a page with a list of payment options, which shows that Nigerian customers can pay for their email lists by wiring the money directly from their bank accounts at several financial institutions in Lagos. BuyEmails.org further advises that, “Due to tremendously high rate of fraudulent payments we do not accept Credit Cards or PayPal. E-Gold has closed, so we don’t accept it either.”

The site sells dozens of country-specific email lists. Other lists are for oddly specific groups. For example, you can buy a list of one million insurance agent emails for $250. 300 beans will let you reach 1.5 million farmers; $400 closes on 4 million real estate agents. Need to recruit a whole mess of money mules right away? No problem: You can buy the email addresses of 6 million prospective work-at-home USA residents for just $99. A list of 1,041,977 USA Seniors (45-70 years old) is selling for $325.

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Adobe Reader, Acrobat Update Nixes Zero Day

April 21, 2011

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Adobe shipped updates to its PDF Reader and Acrobat products today to plug a critical security hole that attackers have been exploiting to break into computers. Fixes are available for Mac, Windows and Linux versions of these software titles.

The patch released today addresses two critical flaws. Adobe pushed out a patch for the standalone Flash Player last week, but that same vulnerable component exists in Adobe Reader and Acrobat. Initially, Adobe said it was only aware of attacks on the Flash Player but, in the the latest advisory, it acknowledged the existence of public reports that hackers have been sending out poisoned PDFs that exploit the Flash flaw. Malwaretracker.com, for example, reported that it was receiving reports of malicious PDFs attacking the Flash bug as early as Apr. 17.

The Reader/Acrobat patch also addresses another critical bug (a flaw in the CoolType library of Reader & Acrobat) that could allow attackers to install malicious software. Not much information is public about this vulnerability, except that Poland’s CERT is credited with reporting it. Adobe spokesperson Wiebke Lips said the company was not aware of any exploits in the wild targeting this bug.

The advisory for the latest version is here. Users on Windows and Macintosh can grab the update using the product’s update mechanism. To manually check for an update, open your Reader or Acrobat and choose Help > Check for Updates.

Are Megabreaches Out? E-Thefts Downsized in 2010

April 19, 2011

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The number of financial and confidential records compromised as a result of data breaches in 2010 fell dramatically compared to previous years, a decrease that cybercrime investigators attribute to a sea-change in the motives and tactics used by criminals to steal information. At the same time, organizations of all sizes are dealing with more frequent and smaller breaches than ever before, and most data thefts continue to result from security weaknesses that are relatively unsophisticated and easy to prevent.

These are some of the conclusions drawn from Verizon‘s fourth annual Data Breach Investigations Report. The report measures data breaches based on compromised records, including the theft of Social Security numbers, intellectual property, and credit card numbers, among other things.

It’s important to note at the outset that Verizon’s report only measures loss in terms of records breached. Many businesses hit by cyber crooks last year lost hundreds of thousands of dollars apiece when thieves stole one set of records, such as their online banking credentials.

The data-rich 74-page study is based on information gleaned from Verizon and U.S. Secret Service investigations into about 800 new data compromise incidents since last year’s report (the study also includes an appendix detailing 30 cybercrime cases investigated by the Dutch National High Tech Crime Unit).

Although the report examines the data from more breaches in a single year than ever before (the total Verizon/US Secret Service dataset from all previous years included just over 900 breaches), Verizon found that the total number of breached records fell from 361 million in 2008 to 144 million in 2009 to just 4 million last year.

A good portion of the report is dedicated to positing what might be responsible for this startling decline, but its authors seem unwilling to let the security industry take any credit for it.

“An optimist may interpret these results as a sign that the security industry is WINNING! Sorry, Charlie”, the report says. “While we’d really like that to be the case, one year just isn’t enough time for such a wholesale improvement in security practices necessary to cut data loss so drastically.”

The study suggests a number of possible explanations. For example:

-There were relatively few huge data heists. Those which had been responsible for the majority of the breached records in the past few years were breaches involving tens of millions of stolen credit and debit cards. Those high profile attacks may have achieved fame and fortune for the attackers, but they also attracted a lot of unwanted attention. Many of the past megabreaches ended in the capture and arrest of those responsible, such the case of Albert Gonzales, the former Secret Service informant who was sentenced last year to 20 years in prison for his role in the theft of 130 million credit and debit card numbers from card processing giant Heartland Payment Systems. “Those that wish to stay out of jail may have changed their goals and tactics to stay under the radar,” the report notes. “This could be one of the chief reasons behind the rash of ‘mini breaches’ involving smaller organizations.”

-Megabreaches of years past flooded criminal underground markets with so many stolen card numbers that their value plummeted. Criminals’ attention may have turned to stealing other lower profile data types, such as bank account credentials, personal information and intellectual property. In other words, criminals might opt to let the markets clear before stealing more huge quantities or selling what they already had purloined. “It’s worth noting that a lot of the cards that were stolen over the last few years in these megabreaches probably are going to start expiring soon,” said Bryan Sartin, director of investigative response at Verizon Business. “So we could be in a holding pattern right now.”

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Time to Patch Your Flash

April 15, 2011

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If it seems like you just updated your Flash Player software to plug a security hole that attackers were using to break into computers, you’re probably not imagining things: Three weeks ago, Adobe rushed out a new version to sew up a critical new security flaw. Today, Adobe issued a critical Flash update to eliminate another dangerous security hole that criminals are actively exploiting.

This new update addresses a vulnerability first detailed here at KrebsOnSecurity.com on Tuesday, and Adobe deserves credit for responding quickly with a patch. But there are few things that are simple about updating Flash, which ships in a dizzying array of version numbers and for many users must be deployed at least twice to cover all browsers. In addition, users may have to uninstall the existing version before updating to guarantee a trouble-free install. Also, Adobe Air will need to be updated if that software also is already installed. Finally, fixing this same vulnerability in Adobe Reader and Acrobat will require installing another patch, which won’t be out for at least another 10 days.

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U.S. Government Takes Down Coreflood Botnet

April 14, 2011

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The U.S. Justice Department and the FBI were granted unprecedented authority this week to seize control over a criminal botnet that enslaved millions of computers and to use that power to disable the malicious software on infected PCs.

Sample network diagram of Coreflood, Source:FBI

The target of the takedown was “Coreflood,” an infamous botnet that emerged almost a decade ago as a high-powered virtual weapon designed to knock targeted Web sites offline. Over the years, the crooks running the botnet began to use it to defraud owners of the victim PCs by stealing bank account information and draining balances.

Coreflood has morphed into a menacing crime machine since its emergence in 2002. As I noted in a 2008 story for The Washington Post, this is the same botnet that was used to steal more than $90,000 from Joe Lopez in 2005, kicking off the first of many high profile lawsuits that would be brought against banks by victims of commercial account takeovers. According to the Justice Department, Coreflood also was implicated in the theft of $241,866 from a defense contractor in Tennessee; $115,771 from a real estate company in Michigan; and $151,201 from an investment firm in North Carolina.

By 2008, Coreflood had infected some 378,000 PCs, including computers at hospitals and government agencies. According to research done by Joe Stewart, senior malware researcher for Dell SecureWorks, the thieves in charge of Coreflood had stolen more than 500 gigabytes of banking credentials and other sensitive data, enough data to fill 500 pickup trucks if printed on paper.

On April 11, 2011, the U.S. Attorney’s Office for the District of Connecticut filed a civil complaint against 13 unknown (“John Doe”) defendants responsible for running Coreflood, and was granted authority to seize 29 domain names used to control the daily operations of the botnet. The government also was awarded a temporary restraining order (TRO) allowing it to send individual PCs infected with Coreflood a command telling the machines to stop the bot software from running.

The government was able to do this because it also won the right to have the Coreflood control servers redirected to networks run by the nonprofit Internet Systems Consortium (ISC). When bots reported to the control servers – as they were programmed to do periodically – the ISC servers would reply with commands telling the bot program to quit.

ISC President Barry Greene said the government was wary of removing the bot software from infected machines.

“They didn’t want to do the uninstall, just exit,” Greene said. “Baby steps. But this was significant for the DOJ to be able to do this. People have been saying we should be able to do this for a long time, and nobody has done what we’re doing until now.”

No U.S. law enforcement authority has ever sought to commandeer a botnet using such an approach. Last year, Dutch authorities took down the Bredolab botnet using a similar method that directed affected users to a Web page warning of the infection. Last month, Microsoft took down the Rustock spam botnet by convincing a court to grant it control over both the botnet’s control domains and the hard drives used by those control servers.

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Microsoft Issues Monster Patch Update

April 13, 2011

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Microsoft released a record number of software updates yesterday to fix at least 64 security vulnerabilities in its Windows operating systems and Office products, including at least one that attackers are actively exploiting.

Updates are available for all versions of Windows via Windows Update or Automatic Update. Nine of the patches earned Microsoft’s “critical” rating, which means the vulnerabilities they fix could be exploited to compromise PCs with little or no action on the part of the user, apart from visiting a booby-trapped Web site or opening a tainted file.

Redmond said three of patches should be top priorities. Two of them fix critical vulnerabilities in the “server message block” or SMB service, which handles Windows networking. Attackers could exploit the flaw addressed by MS11-020 by sending a single, specially crafted evil data packet to a targeted system. This is the type of flaw that should concern any network administrator, because it has high potential to be used to power an automated computer worm.

Microsoft also called attention to MS11-018, which is a cumulative security update for Internet Explorer that fixes critical flaws in all versions of the browser except the latest IE9, which is not affected. One of the IE vulnerabilities — the MHTML flaw I wrote about in January — is currently being exploited; another was discovered at the Pwn2Own hacking competition earlier this year.

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New Adobe Flash Zero Day Being Exploited?

April 11, 2011

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Attackers are exploiting a previously unknown security flaw in Adobe’s ubiquitous Flash Player software to launch targeted attacks, according to several reliable sources. The attacks come less than three weeks after Adobe issued a critical update to fix a different Flash flaw that crooks were similarly exploiting to install malicious software.

According to sources, the attacks exploit a vulnerability in fully-patched versions of Flash, and are being leveraged in targeted spear-phishing campaigns launched against select organizations and individuals that work with or for the U.S. government. Sources say the attacks so far have embedded the Flash exploit inside of Microsoft Word files made to look like important government documents.

Adobe spokesperson Wiebke Lips said the company is currently investigating reports of a new Flash vulnerability, and that Adobe may issue an advisory later today if it is confirmed.

On March 11, Adobe issued a critical update to fix a security hole in Flash that it had earlier said was being attacked via malicious Flash content embedded in Microsoft Excel files. It’s not clear how long attackers have been exploiting this newest Flash flaw, but its exploitation in such a similar manner as the last flaw suggests the attackers may have a ready supply of unknown, unpatched security holes in Flash at their disposal.

Update, 3:57 p.m. ET: Ever wonder what anti-virus detection looks like in the early hours of a zero day outbreak like this? A scan of one tainted file used in this attack that was submitted to Virustotal.com indicates that just one out of 42 anti-virus products used to scan malware at the service detected this thing as malicious.

Update, 4:10 p.m. ET: Removed advice about deleting or renaming authplay.dll, which several readers (and now Adobe) have pointed out is specific to Adobe Reader and Acrobat.

Update, 5:05 p.m. ET: Adobe just released an advisory about this that confirms the above information.

ATM Skimmers: Hacking the Cash Machine

April 10, 2011

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Most of the ATM skimmers I’ve profiled in this blog are comprised of parts designed to mimic and to fit on top of existing cash machine components, such as card acceptance slots or PIN pads. But sometimes, skimmer thieves find success by swapping out ATM parts with compromised look-alikes.

ATM Card skimmer, using modified ATM component

On May 16, 2009, a company representative from ATM maker Diebold was servicing an ATM at a Bank of America branch in Sun Valley, Calif., when he discovered a skimming device and a camera that were attached to the machine. The technician took pictures of the camera and card skimmer (click picture at right for larger image), and then went into the branch to contact his supervisor.

But when the Diebold employee returned, the camera had been removed from the ATM, suggesting that the skimmer scammer was lurking somewhere nearby and had swooped in to salvage his remaining equipment. This is similar to what happened when an ATM technician discovered a compromised ATM a year ago.

Investigators of the present scam learned that the thief had somehow pried off the plastic cover of the ATM’s card acceptance slot and replaced it with an identical, compromised version that included a modified magnetic stripe reader and a flash storage device. The new card slot came with its own clear plastic face that was situated in front of the plastic one that was already attached to the ATM’s internal card reader (see picture below). The entire fraudulent device was glued onto the ATM with silicon.

Below are a few close-ups of the silicon-based magnetic stripe reader attached to the compromised card acceptance slot overlay.

A close-up of an ATM card reader

Here’s a closer look at the electronics inside this handmade reader:

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Is Your Computer Listed “For Rent”?

April 8, 2011

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When it’s time to book a vacation or a quick getaway, many of us turn to travel reservation sites like Expedia, Travelocity and other comparison services. But there’s a cybercrime-friendly booking service that is not well-known. When cyber crooks want to get away — with a crime — increasingly they are turning to underground online booking services that make it easy for crooks to rent hacked PCs that can help them ply their trade anonymously.

We often hear about hacked, remote-controlled PCs or “bots” being used to send spam or to host malicious Web sites, but seldom do security researchers delve into the mechanics behind one of the most basic uses for a bot: To serve as a node in an anonymization service that allows paying customers to proxy their Internet connections through one or more compromised systems.

As I noted in a Washington Post column in 2008, “this type of service is especially appealing to criminals looking to fleece bank accounts at institutions that conduct rudimentary Internet address checks to ensure that the person accessing an account is indeed logged on from the legitimate customer’s geographic region, as opposed to say, Odessa, Ukraine.” Scammers have been using proxies forever it seems, but it’s interesting that it is so easy to find victims, once you are a user of the anonymization service.

Here’s an overview of one of the more advanced anonymity networks on the market, an invite-only subscription service marketed on several key underground cyber crime forums.

When I tested this service, it had more than 4,100 bot proxies available in 75 countries, although the bulk of the hacked PCs being sold or rented were in the United States and the United Kingdom. Also, the number of available proxies fluctuates daily, peaking during normal business hours in the United States. Drilling down into the U.S. map (see image above), users can select proxies by state, or use the “advanced search” box, which allows customers to select bots based on city, IP range, Internet provider, and connection speed. This service also includes a fairly active Russian-language customer support forum. Customers can use the service after paying a one-time $150 registration fee (security deposit?) via a virtual currency such as WebMoney or Liberty Reserve. After that, individual botted systems can be rented for about a dollar a day, or “purchased” for exclusive use for slightly more.

I tried to locate some owners of the hacked machines being rented via this service. Initially this presented a challenge because the majority of the proxies listed are compromised PCs hooked up to home or small business cable modem or DSL connections. As you can see from the screenshot below, the only identifying information for these systems was the IP address and host name. And although so-called “geo-location” services can plot the approximate location of an Internet address, these services are not exact and are sometimes way off.

I started poking through the listings for proxies that had meaningful host names, such as the domain name of a business. It wasn’t long before I stumbled upon the Web site for The Securities Group LLC, a Memphis, Tenn. based privately held broker/dealer firm specializing in healthcare partnerships with physicians. According to the company’s site, “TSG has raised over $100,000,000 having syndicated over 200 healthcare projects including whole hospital exemptions, ambulatory surgery centers, surgical hospitals, PET Imaging facilities, CATH labs and a prostate cancer supplement LLC with up to 400 physician investors.” The proxy being sold by the anonymization service was tied to the Internet address of TSG’s email server, and to the Web site for the Kirby Pines Retirement Community, also in Memphis.

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After Epsilon: Avoiding Phishing Scams & Malware

April 6, 2011

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The recent massive data leak from email services provider Epsilon means that it is likely that many consumers will be exposed to an unusually high number of email-based scams in the coming weeks and months. So this is an excellent time to point out some useful resources and tips that can help readers defend against phishing attacks and other nastygrams.

Don’t take the bait: Many people are familiar with the traditional phishing attack, which arrives in an email that appears to have been sent from your bank or ISP, warning that your account will be suspended unless you take some action immediately, usually clicking a link and “verifying” your account information, user name, password, etc. at a fake site. Commercial emails that emphasize urgency should be always considered extremely suspect, and under no circumstances should you do anything suggested in the email. Phishers count on spooking people into acting rashly because they know their scam sites have a finite lifetime; they may be shuttered at any moment (most phishing scams are hosted on hacked, legitimate Web sites). If you’re really concerned, pick up the phone (gasp!) and call the company to find out if there really is anything for you to be concerned about.

Links Lie: You’re a sucker if you take links at face value. For example, this might look like a link to Bank of America, but I assure you it is not. To get an idea of where a link goes, hover over it with your mouse and then look in the bottom left corner of the browser window. Yet, even this information often tells only part of the story, and some links can be trickier to decipher. For instance, many banks like to send links that include ridiculously long URLs which stretch far beyond the browser’s ability to show the entire thing when you hover over the link. The most important part of a link is the “root” domain. To find that, look for the first slash (/) after the “http://” part, and then work backwards through the link until you reach the second dot; the part immediately to the right is the real domain to which that link will take you. Want to learn more cool stuff about links? Check out this guy’s site and you’ll be a link ninja in no time.

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