Breach at Hy-Vee Supermarket Chain Tied to Sale of 5M+ Stolen Credit, Debit Cards

August 22, 2019
82 Comments

On Tuesday of this week, one of the more popular underground stores peddling credit and debit card data stolen from hacked merchants announced a blockbuster new sale: More than 5.3 million new accounts belonging to cardholders from 35 U.S. states. Multiple sources now tell KrebsOnSecurity that the card data came from compromised gas pumps, coffee shops and restaurants operated by Hy-Vee, an Iowa-based company that operates a chain of more than 245 supermarkets throughout the Midwestern United States.

Hy-Vee, based in Des Moines, announced on Aug. 14 it was investigating a data breach involving payment processing systems that handle transactions at some Hy-Vee fuel pumps, drive-thru coffee shops and restaurants.

The restaurants affected include Hy-Vee Market Grilles, Market Grille Expresses and Wahlburgers locations that the company owns and operates. Hy-Vee said it was too early to tell when the breach initially began or for how long intruders were inside their payment systems.

But typically, such breaches occur when cybercriminals manage to remotely install malicious software on a retailer’s card-processing systems. This type of point-of-sale malware is capable of copying data stored on a credit or debit card’s magnetic stripe when those cards are swiped at compromised payment terminals. This data can then be used to create counterfeit copies of the cards.

Hy-Vee said it believes the breach does not affect payment card terminals used at its grocery store checkout lanes, pharmacies or convenience stores, as these systems rely on a security technology designed to defeat card-skimming malware.

“These locations have different point-of-sale systems than those located at our grocery stores, drugstores and inside our convenience stores, which utilize point-to-point encryption technology for processing payment card transactions,” Hy-Vee said. “This encryption technology protects card data by making it unreadable. Based on our preliminary investigation, we believe payment card transactions that were swiped or inserted on these systems, which are utilized at our front-end checkout lanes, pharmacies, customer service counters, wine & spirits locations, floral departments, clinics and all other food service areas, as well as transactions processed through Aisles Online, are not involved.”

According to two sources who asked not to be identified for this story — including one at a major U.S. financial institution — the card data stolen from Hy-Vee is now being sold under the code name “Solar Energy,” at the infamous Joker’s Stash carding bazaar.

An ad at the Joker’s Stash carding site for “Solar Energy,” a batch of more than 5 million credit and debit cards sources say was stolen from customers of supermarket chain Hy-Vee.

Hy-Vee said the company’s investigation is continuing.

“We are aware of reports from payment processors and the card networks of payment data being offered for sale and are working with the payment card networks so that they can identify the cards and work with issuing banks to initiate heightened monitoring on accounts,” Hy-Vee spokesperson Tina Pothoff said. Continue reading →

Forced Password Reset? Check Your Assumptions

August 21, 2019
110 Comments

Almost weekly now I hear from an indignant reader who suspects a data breach at a Web site they frequent that has just asked the reader to reset their password. Further investigation almost invariably reveals that the password reset demand was not the result of a breach but rather the site’s efforts to identify customers who are reusing passwords from other sites that have already been hacked.

But ironically, many companies taking these proactive steps soon discover that their explanation as to why they’re doing it can get misinterpreted as more evidence of lax security. This post attempts to unravel what’s going on here.

Over the weekend, a follower on Twitter included me in a tweet sent to California-based job search site Glassdoor, which had just sent him the following notice:

The Twitter follower expressed concern about this message, because it suggested to him that in order for Glassdoor to have done what it described, the company would have had to be storing its users’ passwords in plain text. I replied that this was in fact not an indication of storing passwords in plain text, and that many companies are now testing their users’ credentials against lists of hacked credentials that have been leaked and made available online.

The reality is Facebook, Netflix and a number of big-name companies are regularly combing through huge data leak troves for credentials that match those of their customers, and then forcing a password reset for those users. Some are even checking for password re-use on all new account signups.

The idea here is to stymie a massively pervasive problem facing all companies that do business online today: Namely, “credential-stuffing attacks,” in which attackers take millions or even billions of email addresses and corresponding cracked passwords from compromised databases and see how many of them work at other online properties.

So how does the defense against this daily deluge of credential stuffing work? A company employing this strategy will first extract from these leaked credential lists any email addresses that correspond to their current user base.

From there, the corresponding cracked (plain text) passwords are fed into the same process that the company relies upon when users log in: That is, the company feeds those plain text passwords through its own password “hashing” or scrambling routine.

Password hashing is designed to be a one-way function which scrambles a plain text password so that it produces a long string of numbers and letters. Not all hashing methods are created equal, and some of the most commonly used methods — MD5 and SHA-1, for example — can be far less secure than others, depending on how they’re implemented (more on that in a moment). Whatever the hashing method used, it’s the hashed output that gets stored, not the password itself.

Back to the process: If a user’s plain text password from a hacked database matches the output of what a company would expect to see after running it through their own internal hashing process, that user is then prompted to change their password to something truly unique. Continue reading →

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The Rise of “Bulletproof” Residential Networks

August 19, 2019
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Cybercrooks increasingly are anonymizing their malicious traffic by routing it through residential broadband and wireless data connections. Traditionally, those connections have been mainly hacked computers, mobile phones, or home routers. But this story is about so-called “bulletproof residential VPN services” that appear to be built by purchasing or otherwise acquiring discrete chunks of Internet addresses from some of the world’s largest ISPs and mobile data providers.

In late April 2019, KrebsOnSecurity received a tip from an online retailer who’d seen an unusual number of suspicious transactions originating from a series of Internet addresses assigned to a relatively new Internet provider based in Maryland called Residential Networking Solutions LLC.

Now, this in itself isn’t unusual; virtually every provider has the occasional customers who abuse their access for fraudulent purposes. But upon closer inspection, several factors caused me to look more carefully at this company, also known as “Resnet.”

An examination of the IP address ranges assigned to Resnet shows that it maintains an impressive stable of IP blocks — totaling almost 70,000 IPv4 addresses — many of which had until quite recently been assigned to someone else.

Most interestingly, about ten percent of those IPs — more than 7,000 of them — had until late 2018 been under the control of AT&T Mobility. Additionally, the WHOIS registration records for each of these mobile data blocks suggest Resnet has been somehow reselling data services for major mobile and broadband providers, including AT&T, Verizon, and Comcast Cable.

The WHOIS records for one of several networks associated with Residential Networking Solutions LLC.

Drilling down into the tracts of IPs assigned to Resnet’s core network indicates those 7,000+ mobile IP addresses under Resnet’s control were given the label  “Service Provider Corporation” — mostly those beginning with IPs in the range 198.228.x.x.

An Internet search reveals this IP range is administered by the Wireless Data Service Provider Corporation (WDSPC), a non-profit formed in the 1990s to manage IP address ranges that could be handed out to various licensed mobile carriers in the United States.

Back when the WDSPC was first created, there were quite a few mobile wireless data companies. But today the vast majority of the IP space managed by the WDSPC is leased by AT&T Mobility and Verizon Wireless — which have gradually acquired most of their competing providers over the years.

A call to the WDSPC revealed the nonprofit hadn’t leased any new wireless data IP space in more than 10 years. That is, until the organization received a communication at the beginning of this year that it believed was from AT&T, which recommended Resnet as a customer who could occupy some of the company’s mobile data IP address blocks.

“I’m afraid we got duped,” said the person answering the phone at the WDSPC, while declining to elaborate on the precise nature of the alleged duping or the medium that was used to convey the recommendation.

AT&T declined to discuss its exact relationship with Resnet  — or if indeed it ever had one to begin with. It responded to multiple questions about Resnet with a short statement that said, “We have taken steps to terminate this company’s services and have referred the matter to law enforcement.”

Why exactly AT&T would forward the matter to law enforcement remains unclear. But it’s not unheard of for hosting providers to forge certain documents in their quest for additional IP space, and anyone caught doing so via email, phone or fax could be charged with wire fraud, which is a federal offense that carries punishments of up to $500,000 in fines and as much as 20 years in prison.

WHAT IS RESNET?

The WHOIS registration records for Resnet’s main Web site, resnetworking[.]com, are hidden behind domain privacy protection. However, a cursory Internet search on that domain turned up plenty of references to it on Hackforums[.]net, a sprawling community that hosts a seemingly never-ending supply of up-and-coming hackers seeking affordable and anonymous ways to monetize various online moneymaking schemes.

One user in particular — a Hackforums member who goes by the nickname “Profitvolt” — has spent several years advertising resnetworking[.]com and a number of related sites and services, including “unlimited” AT&T 4G/LTE data services, and the immediate availability of more than 1 million residential IPs that he suggested were “perfect for botting, shoe buying.”

The Hackforums user “Profitvolt” advertising residential proxies.

Profitvolt advertises his mobile and residential data services as ideal for anyone who wishes to run “various bots,” or “advertising campaigns.” Those services are meant to provide anonymity when customers are doing things such as automating ad clicks on platforms like Google Adsense and Facebook; generating new PayPal accounts; sneaker bot activity; credential stuffing attacks; and different types of social media spam.

For readers unfamiliar with this term, “shoe botting” or “sneaker bots” refers to the use of automated bot programs and services that aid in the rapid acquisition of limited-release, highly sought-after designer shoes that can then be resold at a profit on secondary markets. All too often, it seems, the people who profit the most in this scheme are using multiple sets of compromised credentials from consumer accounts at online retailers, and/or stolen payment card data.

To say shoe botting has become a thorn in the side of online retailers and regular consumers alike would be a major understatement: A recent State of The Internet Security Report (PDF) from Akamai (an advertiser on this site) noted that such automated bot activity now accounts for almost half of the Internet bandwidth directed at online retailers. The prevalance of shoe botting also might help explain Footlocker‘s recent $100 million investment in goat.com, the largest secondary shoe resale market on the Web.

In other discussion threads, Profitvolt advertises he can rent out an “unlimited number” of so-called “residential proxies,” a term that describes home or mobile Internet connections that can be used to anonymously relay Internet traffic for a variety of dodgy deals.

From a ne’er-do-well’s perspective, the beauty of routing one’s traffic through residential IPs is that few online businesses will bother to block malicious or suspicious activity emanating from them.

That’s because in general the pool of IP addresses assigned to residential or mobile wireless connections cycles intermittently from one user to the next, meaning that blacklisting one residential IP for abuse or malicious activity may only serve to then block legitimate traffic (and e-commerce) from the next user who gets assigned that same IP. Continue reading →

Meet Bluetana, the Scourge of Pump Skimmers

August 14, 2019
81 Comments

“Bluetana,” a new mobile app that looks for Bluetooth-based payment card skimmers hidden inside gas pumps, is helping police and state employees more rapidly and accurately locate compromised fuel stations across the nation, a study released this week suggests. Data collected in the course of the investigation also reveals some fascinating details that may help explain why these pump skimmers are so lucrative and ubiquitous.

The new app, now being used by agencies in several states, is the brainchild of computer scientists from the University of California San Diego and the University of Illinois Urbana-Champaign, who say they developed the software in tandem with technical input from the U.S. Secret Service (the federal agency most commonly called in to investigate pump skimming rings).

The Bluetooth pump skimmer scanner app ‘Bluetana’ in action.

Gas pumps are a perennial target of skimmer thieves for several reasons. They are usually unattended, and in too many cases a handful of master keys will open a great many pumps at a variety of filling stations.

The skimming devices can then be attached to electronics inside the pumps in a matter of seconds, and because they’re also wired to the pump’s internal power supply the skimmers can operate indefinitely without the need of short-lived batteries.

And increasingly, these pump skimmers are fashioned to relay stolen card data and PINs via Bluetooth wireless technology, meaning the thieves who install them can periodically download stolen card data just by pulling up to a compromised pump and remotely connecting to it from a Bluetooth-enabled mobile device or laptop.

According to the study, some 44 volunteers  — mostly law enforcement officials and state employees — were equipped with Bluetana over a year-long experiment to test the effectiveness of the scanning app.

The researchers said their volunteers collected Bluetooth scans at 1,185 gas stations across six states, and that Bluetana detected a total of 64 skimmers across four of those states. All of the skimmers were later collected by law enforcement, including two that were reportedly missed in manual safety inspections of the pumps six months earlier.

While several other Android-based apps designed to find pump skimmers are already available, the researchers said Bluetana was developed with an eye toward eliminating false-positives that some of these other apps can fail to distinguish.

“Bluetooth technology used in these skimmers are also used for legitimate products commonly seen at and near gas stations such as speed-limit signs, weather sensors and fleet tracking systems,” said Nishant Bhaskar, UC San Diego Ph.D. student and principal author of the study. “These products can be mistaken for skimmers by existing detection apps.” Continue reading →

Patch Tuesday, August 2019 Edition

August 13, 2019
134 Comments

Most Microsoft Windows (ab)users probably welcome the monthly ritual of applying security updates about as much as they look forward to going to the dentist: It always seems like you were there just yesterday, and you never quite know how it’s all going to turn out. Fortunately, this month’s patch batch from Redmond is mercifully light, at least compared to last month.

Okay, maybe a trip to the dentist’s office is still preferable. In any case, today is the second Tuesday of the month, which means it’s once again Patch Tuesday (or — depending on your setup and when you’re reading this post — Reboot Wednesday). Microsoft today released patches to fix some 93 vulnerabilities in Windows and related software, 35 of which affect various Server versions of Windows, and another 70 that apply to the Windows 10 operating system.

Although there don’t appear to be any zero-day vulnerabilities fixed this month — i.e. those that get exploited by cybercriminals before an official patch is available — there are several issues that merit attention.

Chief among those are patches to address four moderately terrifying flaws in Microsoft’s Remote Desktop Service, a feature which allows users to remotely access and administer a Windows computer as if they were actually seated in front of the remote computer. Security vendor Qualys says two of these weaknesses can be exploited remotely without any authentication or user interaction.

“According to Microsoft, at least two of these vulnerabilities (CVE-2019-1181 and CVE-2019-1182) can be considered ‘wormable’ and [can be equated] to BlueKeep,” referring to a dangerous bug patched earlier this year that Microsoft warned could be used to spread another WannaCry-like ransomware outbreak. “It is highly likely that at least one of these vulnerabilities will be quickly weaponized, and patching should be prioritized for all Windows systems.”

Fortunately, Remote Desktop is disabled by default in Windows 10, and as such these flaws are more likely to be a threat for enterprises that have enabled the application for various purposes. For those keeping score, this is the fourth time in 2019 Microsoft has had to fix critical security issues with its Remote Desktop service.

For all you Microsoft Edge and Internet Exploiter Explorer users, Microsoft has issued the usual panoply of updates for flaws that could be exploited to install malware after a user merely visits a hacked or booby-trapped Web site. Other equally serious flaws patched in Windows this month could be used to compromise the operating system just by convincing the user to open a malicious file (regardless of which browser the user is running). Continue reading →

SEC Investigating Data Leak at First American Financial Corp.

August 12, 2019
29 Comments

The U.S. Securities and Exchange Commission (SEC) is investigating a security failure on the Web site of real estate title insurance giant First American Financial Corp. that exposed more than 885 million personal and financial records tied to mortgage deals going back to 2003, KrebsOnSecurity has learned.

First American Financial Corp.

In May, KrebsOnSecurity broke the news that the Web site for Santa Ana, Calif.-based First American [NYSE:FAF] exposed some 885 million documents related to real estate closings over the past 16 years, including bank account numbers and statements, mortgage and tax records, Social Security numbers, wire transaction receipts and drivers license images. No authentication was required to view the documents.

The initial tip on that story came from Ben Shoval, a real estate developer based in Seattle. Shoval said he recently received a letter from the SEC’s enforcement division which stated the agency was investigating the data exposure to determine if First American had violated federal securities laws.

In its letter, the SEC asked Shoval to preserve and share any documents or evidence he had related to the data exposure.

“This investigation is a non-public, fact-finding inquiry,” the letter explained. “The investigation does not mean that we have concluded that anyone has violated the law.”

The SEC declined to comment for this story.

Word of the SEC investigation comes weeks after regulators in New York said they were investigating the company in what could turn out to be the first test of the state’s strict new cybersecurity regulation, which requires financial companies to periodically audit and report on how they protect sensitive data, and provides for fines in cases where violations were reckless or willful. First American also is now the target of a class action lawsuit that alleges it “failed to implement even rudimentary security measures.” Continue reading →

iNSYNQ Ransom Attack Began With Phishing Email

August 9, 2019
39 Comments

A ransomware outbreak that hit QuickBooks cloud hosting firm iNSYNQ in mid-July appears to have started with an email phishing attack that snared an employee working in sales for the company, KrebsOnSecurity has learned. It also looks like the intruders spent roughly ten days rooting around iNSYNQ’s internal network to properly stage things before unleashing the ransomware. iNSYNQ ultimately declined to pay the ransom demand, and it is still working to completely restore customer access to files.

Some of this detail came in a virtual “town hall” meeting held August 8, in which iNSYNQ chief executive Elliot Luchansky briefed customers on how it all went down, and what the company is doing to prevent such outages in the future.

A great many iNSYNQ’s customers are accountants, and when the company took its network offline on July 16 in response to the ransomware outbreak, some of those customers took to social media to complain that iNSYNQ was stonewalling them.

“We could definitely have been better prepared, and it’s totally unacceptable,” Luchansky told customers. “I take full responsibility for this. People waiting ridiculous amounts of time for a response is unacceptable.”

By way of explaining iNSYNQ’s initial reluctance to share information about the particulars of the attack early on, Luchansky told customers the company had to assume the intruders were watching and listening to everything iNSYNQ was doing to recover operations and data in the wake of the ransomware outbreak.

“That was done strategically for a good reason,” he said. “There were human beings involved with [carrying out] this attack in real time, and we had to assume they were monitoring everything we could say. And that posed risks based on what we did say publicly while the ransom negotiations were going on. It could have been used in a way that would have exposed customers even more. That put us in a really tough bind, because transparency is something we take very seriously. But we decided it was in our customers’ best interests to not do that.”

A paid ad that comes up prominently when one searches for “insynq” in Google.

Luchansky did not say how much the intruders were demanding, but he mentioned two key factors that informed the company’s decision not to pay up.

“It was a very substantial amount, but we had the money wired and were ready to pay it in cryptocurrency in the case that it made sense to do so,” he told customers. “But we also understood [that paying] would put a target on our heads in the future, and even if we actually received the decryption key, that wasn’t really the main issue here. Because of the quick reaction we had, we were able to contain the encryption part” to roughly 50 percent of customer systems, he said.

Luchansky said the intruders seeded its internal network with MegaCortex, a potent new ransomware strain first spotted just a couple of months ago that is being used in targeted attacks on enterprises. He said the attack appears to have been carefully planned out in advance and executed “with human intervention all the way through.”

“They decided they were coming after us,” he said. “It’s one thing to prepare for these sorts of events but it’s an entirely different experience to deal with first hand.”

According to an analysis of MegaCortex published this week by Accenture iDefense, the crooks behind this ransomware strain are targeting businesses — not home users — and demanding ransom payments in the range of two to 600 bitcoins, which is roughly $20,000 to $5.8 million.

“We are working for profit,” reads the ransom note left behind by the latest version of MegaCortex. “The core of this criminal business is to give back your valuable data in the original form (for ransom of course).”

A portion of the ransom note left behind by the latest version of MegaCortex. Image: Accenture iDefense.

Continue reading →

Who Owns Your Wireless Service? Crooks Do.

August 7, 2019
99 Comments

Incessantly annoying and fraudulent robocalls. Corrupt wireless company employees taking hundreds of thousands of dollars in bribes to unlock and hijack mobile phone service. Wireless providers selling real-time customer location data, despite repeated promises to the contrary. A noticeable uptick in SIM-swapping attacks that lead to multi-million dollar cyberheists.

If you are somehow under the impression that you — the customer — are in control over the security, privacy and integrity of your mobile phone service, think again. And you’d be forgiven if you assumed the major wireless carriers or federal regulators had their hands firmly on the wheel.

No, a series of recent court cases and unfortunate developments highlight the sad reality that the wireless industry today has all but ceded control over this vital national resource to cybercriminals, scammers, corrupt employees and plain old corporate greed.

On Tuesday, Google announced that an unceasing deluge of automated robocalls had doomed a feature of its Google Voice service that sends transcripts of voicemails via text message.

Google said “certain carriers” are blocking the delivery of these messages because all too often the transcripts resulted from unsolicited robocalls, and that as a result the feature would be discontinued by Aug. 9. This is especially rich given that one big reason people use Google Voice in the first place is to screen unwanted communications from robocalls, mainly because the major wireless carriers have shown themselves incapable or else unwilling to do much to stem the tide of robocalls targeting their customers.

AT&T in particular has had a rough month. In July, the Electronic Frontier Foundation (EFF) filed a class action lawsuit on behalf of AT&T customers in California to stop the telecom giant and two data location aggregators from allowing numerous entities — including bounty hunters, car dealerships, landlords and stalkers — to access wireless customers’ real-time locations without authorization.

And on Monday, the U.S. Justice Department revealed that a Pakistani man was arrested and extradited to the United States to face charges of bribing numerous AT&T call-center employees to install malicious software and unauthorized hardware as part of a scheme to fraudulently unlock cell phones.

Ars Technica reports the scam resulted in millions of phones being removed from AT&T service and/or payment plans, and that the accused allegedly paid insiders hundreds of thousands of dollars to assist in the process.

We should all probably be thankful that the defendant in this case wasn’t using his considerable access to aid criminals who specialize in conducting unauthorized SIM swaps, an extraordinarily invasive form of fraud in which scammers bribe or trick employees at mobile phone stores into seizing control of the target’s phone number and diverting all texts and phone calls to the attacker’s mobile device.

Late last month, a federal judge in New York rejected a request by AT&T to dismiss a $224 million lawsuit over a SIM-swapping incident that led to $24 million in stolen cryptocurrency.

The defendant in that case, 21-year-old Manhattan resident Nicholas Truglia, is alleged to have stolen more than $80 million from victims of SIM swapping, but he is only one of many individuals involved in this incredibly easy, increasingly common and lucrative scheme. The plaintiff in that case alleges that he was SIM-swapped on two different occasions, both allegedly involving crooked or else clueless employees at AT&T wireless stores.

And let’s not forget about all the times various hackers figured out ways to remotely use a carrier’s own internal systems for looking up personal and account information on wireless subscribers.

So what the fresh hell is going on here? And is there any hope that lawmakers or regulators will do anything about these persistent problems? Gigi Sohn, a distinguished fellow at the Georgetown Institute for Technology Law and Policy, said the answer — at least in this administration — is probably a big “no.”

“The takeaway here is the complete and total abdication of any oversight of the mobile wireless industry,” Sohn told KrebsOnSecurity. “Our enforcement agencies aren’t doing anything on these topics right now, and we have a complete and total breakdown of oversight of these incredibly powerful and important companies.” Continue reading →

The Risk of Weak Online Banking Passwords

August 5, 2019
116 Comments

If you bank online and choose weak or re-used passwords, there’s a decent chance your account could be pilfered by cyberthieves — even if your bank offers multi-factor authentication as part of its login process. This story is about how crooks increasingly are abusing third-party financial aggregation services like Mint, Plaid, Yodlee, YNAB and others to surveil and drain consumer accounts online.

Crooks are constantly probing bank Web sites for customer accounts protected by weak or recycled passwords. Most often, the attacker will use lists of email addresses and passwords stolen en masse from hacked sites and then try those same credentials to see if they permit online access to accounts at a range of banks.

A screenshot of a password-checking tool being used to target Chase Bank customers who re-use passwords from other sites. Image: Hold Security.

From there, thieves can take the list of successful logins and feed them into apps that rely on application programming interfaces (API)s from one of several personal financial data aggregators which help users track their balances, budgets and spending across multiple banks.

A number of banks that do offer customers multi-factor authentication — such as a one-time code sent via text message or an app — have chosen to allow these aggregators the ability to view balances and recent transactions without requiring that the aggregator service supply that second factor. That’s according to Brian Costello, vice president of data strategy at Yodlee, one of the largest financial aggregator platforms.

Costello said while some banks have implemented processes which pass through multi-factor authentication (MFA) prompts when consumers wish to link aggregation services, many have not.

“Because we have become something of a known quantity with the banks, we’ve set up turning off MFA with many of them,” Costello said.  “Many of them are substituting coming from a Yodlee IP or agent as a factor because banks have historically been relying on our security posture to help them out.”

Such reconnaissance helps lay the groundwork for further attacks: If the thieves are able to access a bank account via an aggregator service or API, they can view the customer’s balance(s) and decide which customers are worthy of further targeting.

This targeting can occur in at least one of two ways. The first involves spear phishing attacks to gain access to that second authentication factor, which can be made much more convincing once the attackers have access to specific details about the customer’s account — such as recent transactions or account numbers (even partial account numbers).

The second is through an unauthorized SIM swap, a form of fraud in which scammers bribe or trick employees at mobile phone stores into seizing control of the target’s phone number and diverting all texts and phone calls to the attacker’s mobile device.

But beyond targeting customers for outright account takeovers, the data available via financial aggregators enables a far more insidious type of fraud: The ability to link the target’s bank account(s) to other accounts that the attackers control.

That’s because PayPal, Zelle, and a number of other pure-play online financial institutions allow customers to link accounts by verifying the value of microdeposits. For example, if you wish to be able to transfer funds between PayPal and a bank account, the company will first send a couple of tiny deposits  — a few cents, usually — to the account you wish to link. Only after verifying those exact amounts will the account-linking request be granted. Continue reading →

What We Can Learn from the Capital One Hack

August 2, 2019
87 Comments

On Monday, a former Amazon employee was arrested and charged with stealing more than 100 million consumer applications for credit from Capital One. Since then, many have speculated the breach was perhaps the result of a previously unknown “zero-day” flaw, or an “insider” attack in which the accused took advantage of access surreptitiously obtained from her former employer. But new information indicates the methods she deployed have been well understood for years.

What follows is based on interviews with almost a dozen security experts, including one who is privy to details about the ongoing breach investigation. Because this incident deals with somewhat jargon-laced and esoteric concepts, much of what is described below has been dramatically simplified. Anyone seeking a more technical explanation of the basic concepts referenced here should explore some of the many links included in this story.

According to a source with direct knowledge of the breach investigation, the problem stemmed in part from a misconfigured open-source Web Application Firewall (WAF) that Capital One was using as part of its operations hosted in the cloud with Amazon Web Services (AWS).

Known as “ModSecurity,” this WAF is deployed along with the open-source Apache Web server to provide protections against several classes of vulnerabilities that attackers most commonly use to compromise the security of Web-based applications.

The misconfiguration of the WAF allowed the intruder to trick the firewall into relaying requests to a key back-end resource on the AWS platform. This resource, known as the “metadata” service, is responsible for handing out temporary information to a cloud server, including current credentials sent from a security service to access any resource in the cloud to which that server has access.

In AWS, exactly what those credentials can be used for hinges on the permissions assigned to the resource that is requesting them. In Capital One’s case, the misconfigured WAF for whatever reason was assigned too many permissions, i.e. it was allowed to list all of the files in any buckets of data, and to read the contents of each of those files.

The type of vulnerability exploited by the intruder in the Capital One hack is a well-known method called a “Server Side Request Forgery” (SSRF) attack, in which a server (in this case, CapOne’s WAF) can be tricked into running commands that it should never have been permitted to run, including those that allow it to talk to the metadata service.

Evan Johnson, manager of the product security team at Cloudflare, recently penned an easily digestible column on the Capital One hack and the challenges of detecting and blocking SSRF attacks targeting cloud services. Johnson said it’s worth noting that SSRF attacks are not among the dozen or so attack methods for which detection rules are shipped by default in the WAF exploited as part of the Capital One intrusion.

“SSRF has become the most serious vulnerability facing organizations that use public clouds,” Johnson wrote. “The impact of SSRF is being worsened by the offering of public clouds, and the major players like AWS are not doing anything to fix it. The problem is common and well-known, but hard to prevent and does not have any mitigations built into the AWS platform.”

Johnson said AWS could address this shortcoming by including extra identifying information in any request sent to the metadata service, as Google has already done with its cloud hosting platform. He also acknowledged that doing so could break a lot of backwards compatibility within AWS.

“There’s a lot of specialized knowledge that comes with operating a service within AWS, and to someone without specialized knowledge of AWS, [SSRF attacks are] not something that would show up on any critical configuration guide,” Johnson said in an interview with KrebsOnSecurity.

“You have to learn how EC2 works, understand Amazon’s Identity and Access Management (IAM) system, and how to authenticate with other AWS services,” he continued. “A lot of people using AWS will interface with dozens of AWS services and write software that orchestrates and automates new services, but in the end people really lean into AWS a ton, and with that comes a lot of specialized knowledge that is hard to learn and hard to get right.”

In a statement provided to KrebsOnSecurity, Amazon said it is inaccurate to argue that the Capital One breach was caused by AWS IAM, the instance metadata service, or the AWS WAF in any way.

“The intrusion was caused by a misconfiguration of a web application firewall and not the underlying infrastructure or the location of the infrastructure,” the statement reads. “AWS is constantly delivering services and functionality to anticipate new threats at scale, offering more security capabilities and layers than customers can find anywhere else including within their own datacenters, and when broadly used, properly configured and monitored, offer unmatched security—and the track record for customers over 13+ years in securely using AWS provides unambiguous proof that these layers work.”

Amazon pointed to several (mostly a la carte) services it offers AWS customers to help mitigate many of the threats that were key factors in this breach, including:

–Access Advisor, which helps identify and scope down AWS roles that may have more permissions than they need;
–GuardDuty, designed to raise alarms when someone is scanning for potentially vulnerable systems or moving unusually large amounts of data to or from unexpected places;
–The AWS WAF, which Amazon says can detect common exploitation techniques, including SSRF attacks;
–Amazon Macie, designed to automatically discover, classify and protect sensitive data stored in AWS.

William Bengston, formerly a senior security engineer at Netflix, wrote a series of blog posts last year on how Netflix built its own systems for detecting and preventing credential compromises in AWS. Interestingly, Bengston was hired roughly two months ago to be director of cloud security for Capital One. My guess is Capital One now wishes they had somehow managed to lure him away sooner. Continue reading →