Latest Warnings


11
Apr 18

When Identity Thieves Hack Your Accountant

The Internal Revenue Service has been urging tax preparation firms to step up their cybersecurity efforts this year, warning that identity thieves and hackers increasingly are targeting certified public accountants (CPAs) in a bid to siphon oodles of sensitive personal and financial data on taxpayers. This is the story of a CPA in New Jersey whose compromise by malware led to identity theft and phony tax refund requests filed on behalf of his clients.

Last month, KrebsOnSecurity was alerted by security expert Alex Holden of Hold Security about a malware gang that appears to have focused on CPAs. The crooks in this case were using a Web-based keylogger that recorded every keystroke typed on the target’s machine, and periodically uploaded screenshots of whatever was being displayed on the victim’s computer screen at the time.

If you’ve never seen one of these keyloggers in action, viewing their output can be a bit unnerving. This particular malware is not terribly sophisticated, but nevertheless is quite effective. It not only grabs any data the victim submits into Web-based forms, but also captures any typing — including backspaces and typos as we can see in the screenshot below.

The malware records everything its victims type (including backspaces and typos), and frequently takes snapshots of the victim’s computer screen.

Whoever was running this scheme had all victim information uploaded to a site that was protected from data scraping by search engines, but the site itself did not require any form of authentication to view data harvested from victim PCs. Rather, the stolen information was indexed by victim and ordered by day, meaning anyone who knew the right URL could view each day’s keylogging record as one long image file.

Those records suggest that this particular CPA — “John,” a New Jersey professional whose real name will be left out of this story — likely had his computer compromised sometime in mid-March 2018 (at least, this is as far back as the keylogging records go for John).

It’s also not clear exactly which method the thieves used to get malware on John’s machine. Screenshots for John’s account suggest he routinely ignored messages from Microsoft and other third party Windows programs about the need to apply critical security updates.

Messages like this one — about critical security updates available for QuickBooks — went largely ignored, according to multiple screenshots from John’s computer.

More likely, however, John’s computer was compromised by someone who sent him a booby-trapped email attachment or link. When one considers just how frequently CPAs must need to open Microsoft Office and other files submitted by clients and potential clients via email, it’s not hard to imagine how simple it might be for hackers to target and successfully compromise your average CPA.

The keylogging malware itself appears to have been sold (or perhaps directly deployed) by a cybercriminal who uses the nickname ja_far. This individual markets a $50 keylogger product alongside a malware “crypting” service that guarantees his malware will be undetected by most antivirus products for a given number of days after it is used against a victim.

Ja_far’s sales threads for the keylogger used to steal tax and financial data from hundreds of John’s clients.

It seems likely that ja_far’s keylogger was the source of this data because at one point — early in the morning John’s time — the attacker appears to have accidentally pasted ja_far’s jabber instant messenger address into the victim’s screen instead of his own. In all likelihood, John’s assailant was seeking additional crypting services to ensure the keylogger remained undetected on John’s PC. A couple of minutes later, the intruder downloaded a file to John’s PC from file-sharing site sendspace.com.

The attacker apparently messing around on John’s computer while John was not sitting in front of the keyboard.

What I found remarkable about John’s situation was despite receiving notice after notice that the IRS had rejected many of his clients’ tax returns because those returns had already been filed by fraudsters, for at least two weeks John does not appear to have suspected that his compromised computer was likely the source of said fraud inflicted on his clients (or if he did, he didn’t share this notion with any of his friends or family via email).

Instead, John composed and distributed to his clients a form letter about their rejected returns, and another letter that clients could use to alert the IRS and New Jersey tax authorities of suspected identity fraud. Continue reading →


9
Apr 18

Don’t Give Away Historic Details About Yourself

Social media sites are littered with seemingly innocuous little quizzes, games and surveys urging people to reminisce about specific topics, such as “What was your first job,” or “What was your first car?” The problem with participating in these informal surveys is that in doing so you may be inadvertently giving away the answers to “secret questions” that can be used to unlock access to a host of your online identities and accounts.

I’m willing to bet that a good percentage of regular readers here would never respond — honestly or otherwise — to such questionnaires (except perhaps to chide others for responding). But I thought it was worth mentioning because certain social networks — particularly Facebook — seem positively overrun with these data-harvesting schemes. What’s more, I’m constantly asking friends and family members to stop participating in these quizzes and to stop urging their contacts to do the same.

On the surface, these simple questions may be little more than an attempt at online engagement by otherwise well-meaning companies and individuals. Nevertheless, your answers to these questions may live in perpetuity online, giving identity thieves and scammers ample ammunition to start gaining backdoor access to your various online accounts.

Consider, for example, the following quiz posted to Facebook by San Benito Tire Pros, a tire and auto repair shop in California. It asks Facebook users, “What car did you learn to drive stick shift on?”

I hope this is painfully obvious, but for many people the answer will be the same as to the question, “What was the make and model of your first car?”, which is one of several “secret questions” most commonly used by banks and other companies to let customers reset their passwords or gain access to the account without knowing the password.

This simple one-question quiz has been shared more than 250 times on Facebook since it was posted a week ago. Thousands of Facebook users responded in earnest, and in so doing linked their profile to the answer.

Probably the most well-known and common secret question, “what was the name of your first pet,” comes up in a number of Facebook quizzes that, incredibly, thousands of people answer willingly and (apparently) truthfully. When I saw this one I was reminded of this hilarious 2007 Daily Show interview wherein Jon Stewart has Microsoft co-founder Bill Gates on and tries to slyly ask him the name of his first pet.

Almost 5,000 Facebook users answered this common password reset secret question.

Continue reading →


4
Apr 18

Dot-cm Typosquatting Sites Visited 12M Times So Far in 2018

A story published here last week warned readers about a vast network of potentially malicious Web sites ending in “.cm” that mimic some of the world’s most popular Internet destinations (e.g. espn[dot]cm, aol[dot]cm and itunes[dot].cm) in a bid to bombard visitors with fake security alerts that can lock up one’s computer. If that piece lacked one key detail it was insight into just how many people were mistyping .com and ending up at one of these so-called “typosquatting” domains.

On March 30, an eagle-eyed reader noted that four years of access logs for the entire network of more than 1,000 dot-cm typosquatting domains were available for download directly from the typosquatting network’s own hosting provider. The logs — which include detailed records of how many people visited the sites over the past three years and from where — were deleted shortly after that comment was posted here, but not before KrebsOnSecurity managed to grab a copy of the entire archive for analysis.

The geographic distribution of 25,000 randomly selected Internet addresses (IP addresses) in the logs seen accessing the dot-cm typosquatting domains in February 2018. Batchgeo, the service used to produce this graphic, limits free lookups to 25,000, but the above image is likely still representative of the overall geographic distribution. Perhaps unsurprisingly, the largest share of traffic is coming from the United States.

Matthew Chambers, a security expert with whom this author worked on the original dot-cm typosquatting story published last week, analyzed the access logs from just the past three months and found the sites were visited approximately 12 million times during the first quarter of 2018.

Chambers said he combed through the logs and weeded out hits from Internet addresses that appeared to be bots or search engine scrapers. Here’s Chambers’ analysis of the 2018 access log data:

January 2018; 3,732,488 visitors
February 2018: 3,799,109 visitors
Mar 2018: 4,275,998 visitors

Total Jan-Mar 2018 is 11.8 million

Those figures suggest that the total number of visits to these typosquatting sites in the first quarter of 2018 was approximately 12 million, or almost 50 million hits per year. Certainly, not everyone visiting these sites will have the experience that Chambers’ users reported (being bombarded with misleading malware alerts and redirected to scammy and spammy Web sites), but it seems clear this network could make its operators a pretty penny regardless of the content that ends up getting served through it. Continue reading →


20
Mar 18

15-Year-old Finds Flaw in Ledger Crypto Wallet

A 15-year-old security researcher has discovered a serious flaw in cryptocurrency hardware wallets made by Ledger, a French company whose popular products are designed to physically safeguard public and private keys used to receive or spend the user’s cryptocurrencies.

Ledger’s Nano-S cryptocurrency hardware wallet. Source: Amazon.

Hardware wallets like those sold by Ledger are designed to protect the user’s private keys from malicious software that might try to harvest those credentials from the user’s computer.  The devices enable transactions via a connection to a USB port on the user’s computer, but they don’t reveal the private key to the PC.

Yet Saleem Rashid, a 15-year-old security researcher from the United Kingdom, discovered a way to acquire the private keys from Ledger devices. Rashid’s method requires an attacker to have physical access to the device, and normally such hacks would be unremarkable because they fall under the #1 rule of security — namely, if an attacker has physical access to your device, then it is not your device anymore.

The trouble is that consumer demand for Ledger’s products has frequently outpaced the company’s ability to produce them (it has sold over a million of its most popular Nano S models to date). This has prompted the company’s chief technology officer to state publicly that Ledger’s built-in security model is so robust that it is safe to purchase their products from a wide range of third-party sellers, including Amazon and eBay.

Ledger’s message to users regarding the lack of anti-tampering mechanisms on its cryptocurrency hardware wallets.

But Rashid discovered that a reseller of Ledger’s products could update the devices with malicious code that would lie in wait for a potential buyer to use it, and then siphon the private key and drain the user’s cryptocurrency account(s) when the user goes to use it.

The crux of the problem is that Ledger’s devices contain a secure processor chip and a non-secure microcontroller chip. The latter is used for a variety of non-security related purposes, from handling the USB connections to displaying text on the Ledger’s digital display, but the two chips still pass information between each other. Rashid found that an attacker could compromise the insecure processor (the microcontroller) on Ledger devices to run malicious code without being detected.

Ledger’s products do contain a mechanism for checking to ensure the code powering the devices has not been modified, but Rashid’s proof-of-concept code — being released today in tandem with an announcement from Ledger about a new firmware update designed to fix the bug — allows an attacker to force the device to sidestep those security checks.

“You’re essentially trusting a non-secure chip not to change what’s displayed on the screen or change what the buttons are saying,” Rashid said in an interview with KrebsOnSecurity. “You can install whatever you want on that non-secure chip, because the code running on there can lie to you.”

Kenneth White, director of the Open Crypto Audit Project, had an opportunity to review Rashid’s findings prior to their publication today. White said he was impressed with the elegance of the proof-of-concept attack code, which Rashid sent to Ledger approximately four months ago. A copy of Rashid’s research paper on the vulnerability is available here (PDF). A video of Rashid demonstrating his attack is below.

White said Rashid’s code subverts the security of the Ledger’s process for generating a backup code for a user’s private key, which relies on a random number generator that can be made to produce non-random results.

“In this case [the attacker] can set it to whatever he wants,” White said. “The victim generates keys and backup codes, but in fact those codes have been predicted by the attacker in advance because he controls the Ledger’s random number generator.”

Rashid said Ledger initially dismissed his findings as implausible. But in a blog post published today, Ledger says it has since fixed the flaw Rashid found — as well as others discovered and reported by different security researchers — in a firmware update that brings Ledger Nano S devices from firmware version 1.3.1 to version 1.4.1 (the company actually released the firmware update on March 6, potentially giving attackers time to reverse engineer Rashid’s method).

The company is still working on an update for its pricier Ledger Blue devices, which company chief security officer Charles Guillemet said should be ready soon. Guillemet said Nano-S devices should alert users that a firmware update is available when the customer first plugs the device into a computer.

“The vulnerability he found was based on the fact that the secure element tries to authenticate the microcontroller, and that authentication is not strong enough,” Guillemet told KrebsOnSecurity. “This update does authentication more tightly so that it’s not possible to fool the user.” Continue reading →


11
Mar 18

Checked Your Credit Since the Equifax Hack?

A recent consumer survey suggests that half of all Americans still haven’t checked their credit report since the Equifax breach last year exposed the Social Security numbers, dates of birth, addresses and other personal information on nearly 150 million people. If you’re in that fifty percent, please make an effort to remedy that soon.

Credit reports from the three major bureaus — Equifax, Experian and TransUnion — can be obtained online for free at annualcreditreport.com — the only Web site mandated by Congress to serve each American a free credit report every year.

Annualcreditreport.com is run by a Florida-based company, but its data is supplied by the major credit bureaus, which struggled mightily to meet consumer demand for free credit reports in the immediate aftermath of the Equifax breach. Personally, I was unable to order a credit report for either me or my wife even two weeks after the Equifax breach went public: The site just kept returning errors and telling us to request the reports in writing via the U.S. Mail.

Based on thousands of comments left here in the days following the Equifax breach disclosure, I suspect many readers experienced the same but forgot to come back and try again. If this describes you, please take a moment this week to order your report(s) (and perhaps your spouse’s) and see if anything looks amiss. If you spot an error or something suspicious, contact the bureau that produced the report to correct the record immediately.

Of course, keeping on top of your credit report requires discipline, and if you’re not taking advantage of all three free reports each year you need to get a plan. My strategy is to put a reminder on our calendar to order a new report every four months or so, each time from a different credit bureau. Continue reading →


8
Mar 18

Look-Alike Domains and Visual Confusion

How good are you at telling the difference between domain names you know and trust and impostor or look-alike domains? The answer may depend on how familiar you are with the nuances of internationalized domain names (IDNs), as well as which browser or Web application you’re using.

For example, how does your browser interpret the following domain? I’ll give you a hint: Despite appearances, it is most certainly not the actual domain for software firm CA Technologies (formerly Computer Associates Intl Inc.), which owns the original ca.com domain name:

https://www.са.com/

Go ahead and click on the link above or cut-and-paste it into a browser address bar. If you’re using Google Chrome, Apple’s Safari, or some recent version of Microsoft‘s Internet Explorer or Edge browsers, you should notice that the address converts to “xn--80a7a.com.” This is called “punycode,” and it allows browsers to render domains with non-Latin alphabets like Cyrillic and Ukrainian.

Below is what it looks like in Edge on Windows 10; Google Chrome renders it much the same way. Notice what’s in the address bar (ignore the “fake site” and “Welcome to…” text, which was added as a courtesy by the person who registered this domain):

The domain https://www.са.com/ as rendered by Microsoft Edge on Windows 10. The rest of the text in the image (beginning with “Welcome to a site…”) was added by the person who registered this test domain, not the browser.

IE, Edge, Chrome and Safari all will convert https://www.са.com/ into its punycode output (xn--80a7a.com), in part to warn visitors about any confusion over look-alike domains registered in other languages. But if you load that domain in Mozilla Firefox and look at the address bar, you’ll notice there’s no warning of possible danger ahead. It just looks like it’s loading the real ca.com:

What the fake ca.com domain looks like when loaded in Mozilla Firefox. A browser certificate ordered from Comodo allows it to include the green lock (https://) in the address bar, adding legitimacy to the look-alike domain. The rest of the text in the image (beginning with “Welcome to a site…”) was added by the person who registered this test domain, not the browser. Click to enlarge.

The domain “xn--80a7a.com” pictured in the first screenshot above is punycode for the Ukrainian letters for “s” (which is represented by the character “c” in Russian and Ukrainian), as well as an identical Ukrainian “a”.

It was registered by Alex Holden, founder of Milwaukee, Wis.-based Hold Security Inc. Holden’s been experimenting with how the different browsers handle punycodes in the browser and via email. Holden grew up in what was then the Soviet Union and speaks both Russian and Ukrainian, and he’s been playing with Cyrillic letters to spell English words in domain names.

Letters like A and O look exactly the same and the only difference is their Unicode value. There are more than 136,000 Unicode characters used to represent letters and symbols in 139 modern and historic scripts, so there’s a ton of room for look-alike or malicious/fake domains.

For example, “a” in Latin is the Unicode value “0061” and in Cyrillic is “0430.”  To a human, the graphical representation for both looks the same, but for a computer there is a huge difference. Internationalized domain names (IDNs) allow domain names to be registered in non-Latin letters (RFC 3492), provided the domain is all in the same language; trying to mix two different IDNs in the same name causes the domain registries to reject the registration attempt.

So, in the Cyrillic alphabet (Russian/Ukrainian), we can spell АТТ, УАНОО, ХВОХ, and so on. As you can imagine, the potential opportunity for impersonation and abuse are great with IDNs. Here’s a snippet from a larger chart Holden put together showing some of the more common ways that IDNs can be made to look like established, recognizable domains:

Image: Hold Security.

Holden also was able to register a valid SSL encryption certificate for https://www.са.com from Comodo.com, which would only add legitimacy to the domain were it to be used in phishing attacks against CA customers by bad guys, for example. Continue reading →


1
Mar 18

Financial Cyber Threat Sharing Group Phished

The Financial Services Information Sharing and Analysis Center (FS-ISAC), an industry forum for sharing data about critical cybersecurity threats facing the banking and finance industries, said today that a successful phishing attack on one of its employees was used to launch additional phishing attacks against FS-ISAC members.

The fallout from the back-to-back phishing attacks appears to have been limited and contained, as many FS-ISAC members who received the phishing attack quickly detected and reported it as suspicious. But the incident is a good reminder to be on your guard, remember that anyone can get phished, and that most phishing attacks succeed by abusing the sense of trust already established between the sender and recipient.

The confidential alert FS-ISAC sent to members about a successful phishing attack that spawned phishing emails coming from the FS-ISAC.

Notice of the phishing incident came in an alert FS-ISAC shared with its members today and obtained by KrebsOnSecurity. It describes an incident on Feb. 28 in which an FS-ISAC employee “clicked on a phishing email, compromising that employee’s login credentials. Using the credentials, a threat actor created an email with a PDF that had a link to a credential harvesting site and was then sent from the employee’s email account to select members, affiliates and employees.”

The alert said while FS-ISAC was already planning and implementing a multi-factor authentication (MFA) solution across all of its email platforms, “unfortunately, this incident happened to an employee that was not yet set up for MFA. We are accelerating our MFA solution across all FS-ISAC assets.”

The FS-ISAC also said it upgraded its Office 365 email version to provide “additional visibility and security.”

In an interview with KrebsOnSecurity, FS-ISAC President and CEO Bill Nelson said his organization has grown significantly in new staff over the past few years to more than 75 people now, including Greg Temm, the FS-ISAC’s chief information risk officer.

“To say I’m disappointed this got through is an understatement,” Nelson said. “We need to accelerate MFA extremely quickly for all of our assets.” Continue reading →


28
Feb 18

How to Fight Mobile Number Port-out Scams

T-Mobile, AT&T and other mobile carriers are reminding customers to take advantage of free services that can block identity thieves from easily “porting” your mobile number out to another provider, which allows crooks to intercept your calls and messages while your phone goes dark. Tips for minimizing the risk of number porting fraud are available below for customers of all four major mobile providers, including Sprint and Verizon.

Unauthorized mobile phone number porting is not a new problem, but T-Mobile said it began alerting customers about it earlier this month because the company has seen a recent uptick in fraudulent requests to have customer phone numbers ported over to another mobile provider’s network.

“We have been alerting customers via SMS that our industry is experiencing a phone number port out scam that could impact them,” T-Mobile said in a written statement. “We have been encouraging them to add a port validation feature, if they’ve not already done so.”

Crooks typically use phony number porting requests when they have already stolen the password for a customer account (either for the mobile provider’s network or for another site), and wish to intercept the one-time password that many companies send to the mobile device to perform two-factor authentication.

Porting a number to a new provider shuts off the phone of the original user, and forwards all calls to the new device. Once in control of the mobile number, thieves can request any second factor that is sent to the newly activated device, such as a one-time code sent via text message or or an automated call that reads the one-time code aloud.

In these cases, the fraudsters can call a customer service specialist at a mobile provider and pose as the target, providing the mark’s static identifiers like name, date of birth, social security number and other information. Often this is enough to have a target’s calls temporarily forwarded to another number, or ported to a different provider’s network.

Port out fraud has been an industry problem for a long time, but recently we’ve seen an uptick in this illegal activity,” T-Mobile said.  “We’re not providing specific metrics, but it’s been enough that we felt it was important to encourage customers to add extra security features to their accounts.”

In a blog post published Tuesday, AT&T said bad guys sometimes use illegal porting to steal your phone number, transfer the number to a device they control and intercept text authentication messages from your bank, credit card issuer or other companies.

“You may not know this has happened until you notice your mobile device has lost service,” reads a post by Brian Rexroad, VP of security relations at AT&T. “Then, you may notice loss of access to important accounts as the attacker changes passwords, steals your money, and gains access to other pieces of your personal information.”

Rexroad says in some cases the thieves just walk into an AT&T store and present a fake ID and your personal information, requesting to switch carriers. Porting allows customers to take their phone number with them when they change phone carriers.

The law requires carriers to provide this number porting feature, but there are ways to reduce the risk of this happening to you. Continue reading →


2
Feb 18

Attackers Exploiting Unpatched Flaw in Flash

Adobe warned on Thursday that attackers are exploiting a previously unknown security hole in its Flash Player software to break into Microsoft Windows computers. Adobe said it plans to issue a fix for the flaw in the next few days, but now might be a good time to check your exposure to this still-ubiquitous program and harden your defenses.

Adobe said a critical vulnerability (CVE-2018-4878) exists in Adobe Flash Player 28.0.0.137 and earlier versions. Successful exploitation could allow an attacker to take control of the affected system.

The software company warns that an exploit for the flaw is being used in the wild, and that so far the attacks leverage Microsoft Office documents with embedded malicious Flash content. Adobe said it plans to address this vulnerability in a release planned for the week of February 5.

According to Adobe’s advisory, beginning with Flash Player 27, administrators have the ability to change Flash Player’s behavior when running on Internet Explorer on Windows 7 and below by prompting the user before playing Flash content. A guide on how to do that is here (PDF). Administrators may also consider implementing Protected View for Office. Protected View opens a file marked as potentially unsafe in Read-only mode.

Continue reading →


27
Jan 18

First ‘Jackpotting’ Attacks Hit U.S. ATMs

ATM “jackpotting” — a sophisticated crime in which thieves install malicious software and/or hardware at ATMs that forces the machines to spit out huge volumes of cash on demand — has long been a threat for banks in Europe and Asia, yet these attacks somehow have eluded U.S. ATM operators. But all that changed this week after the U.S. Secret Service quietly began warning financial institutions that jackpotting attacks have now been spotted targeting cash machines here in the United States.

To carry out a jackpotting attack, thieves first must gain physical access to the cash machine. From there they can use malware or specialized electronics — often a combination of both — to control the operations of the ATM.

A keyboard attached to the ATM port. Image: FireEye

On Jan. 21, 2018, KrebsOnSecurity began hearing rumblings about jackpotting attacks, also known as “logical attacks,” hitting U.S. ATM operators. I quickly reached out to ATM giant NCR Corp. to see if they’d heard anything. NCR said at the time it had received unconfirmed reports, but nothing solid yet.

On Jan. 26, NCR sent an advisory to its customers saying it had received reports from the Secret Service and other sources about jackpotting attacks against ATMs in the United States.

“While at present these appear focused on non-NCR ATMs, logical attacks are an industry-wide issue,” the NCR alert reads. “This represents the first confirmed cases of losses due to logical attacks in the US. This should be treated as a call to action to take appropriate steps to protect their ATMs against these forms of attack and mitigate any consequences.”

The NCR memo does not mention the type of jackpotting malware used against U.S. ATMs. But a source close to the matter said the Secret Service is warning that organized criminal gangs have been attacking stand-alone ATMs in the United States using “Ploutus.D,” an advanced strain of jackpotting malware first spotted in 2013.

According to that source — who asked to remain anonymous because he was not authorized to speak on the record — the Secret Service has received credible information that crooks are activating so-called “cash out crews” to attack front-loading ATMs manufactured by ATM vendor Diebold Nixdorf.

The source said the Secret Service is warning that thieves appear to be targeting Opteva 500 and 700 series Dielbold ATMs using the Ploutus.D malware in a series of coordinated attacks over the past 10 days, and that there is evidence that further attacks are being planned across the country.

“The targeted stand-alone ATMs are routinely located in pharmacies, big box retailers, and drive-thru ATMs,” reads a confidential Secret Service alert sent to multiple financial institutions and obtained by KrebsOnSecurity. “During previous attacks, fraudsters dressed as ATM technicians and attached a laptop computer with a mirror image of the ATMs operating system along with a mobile device to the targeted ATM.

Reached for comment, Diebold shared an alert it sent to customers Friday warning of potential jackpotting attacks in the United States. Diebold’s alert confirms the attacks so far appear to be targeting front-loaded Opteva cash machines.

“As in Mexico last year, the attack mode involves a series of different steps to overcome security mechanism and the authorization process for setting the communication with the [cash] dispenser,” the Diebold security alert reads. A copy of the entire Diebold alert, complete with advice on how to mitigate these attacks, is available here (PDF). Continue reading →