Entries Tagged "banking"

Page 11 of 19

Man-in-the-Middle Attacks

Last week’s dramatic rescue of 15 hostages held by the guerrilla organization FARC was the result of months of intricate deception on the part of the Colombian government. At the center was a classic man-in-the-middle attack.

In a man-in-the-middle attack, the attacker inserts himself between two communicating parties. Both believe they’re talking to each other, and the attacker can delete or modify the communications at will.

The Wall Street Journal reported how this gambit played out in Colombia:

“The plan had a chance of working because, for months, in an operation one army officer likened to a ‘broken telephone,’ military intelligence had been able to convince Ms. Betancourt’s captor, Gerardo Aguilar, a guerrilla known as ‘Cesar,’ that he was communicating with his top bosses in the guerrillas’ seven-man secretariat. Army intelligence convinced top guerrilla leaders that they were talking to Cesar. In reality, both were talking to army intelligence.”

This ploy worked because Cesar and his guerrilla bosses didn’t know one another well. They didn’t recognize one anothers’ voices, and didn’t have a friendship or shared history that could have tipped them off about the ruse. Man-in-the-middle is defeated by context, and the FARC guerrillas didn’t have any.

And that’s why man-in-the-middle, abbreviated MITM in the computer-security community, is such a problem online: Internet communication is often stripped of any context. There’s no way to recognize someone’s face. There’s no way to recognize someone’s voice. When you receive an e-mail purporting to come from a person or organization, you have no idea who actually sent it. When you visit a website, you have no idea if you’re really visiting that website. We all like to pretend that we know who we’re communicating with—and for the most part, of course, there isn’t any attacker inserting himself into our communications—but in reality, we don’t. And there are lots of hacker tools that exploit this unjustified trust, and implement MITM attacks.

Even with context, it’s still possible for MITM to fool both sides—because electronic communications are often intermittent. Imagine that one of the FARC guerrillas became suspicious about who he was talking to. So he asks a question about their shared history as a test: “What did we have for dinner that time last year?” or something like that. On the telephone, the attacker wouldn’t be able to answer quickly, so his ruse would be discovered. But e-mail conversation isn’t synchronous. The attacker could simply pass that question through to the other end of the communications, and when he got the answer back, he would be able to reply.

This is the way MITM attacks work against web-based financial systems. A bank demands authentication from the user: a password, a one-time code from a token or whatever. The attacker sitting in the middle receives the request from the bank and passes it to the user. The user responds to the attacker, who passes that response to the bank. Now the bank assumes it is talking to the legitimate user, and the attacker is free to send transactions directly to the bank. This kind of attack completely bypasses any two-factor authentication mechanisms, and is becoming a more popular identity-theft tactic.

There are cryptographic solutions to MITM attacks, and there are secure web protocols that implement them. Many of them require shared secrets, though, making them useful only in situations where people already know and trust one another.

The NSA-designed STU-III and STE secure telephones solve the MITM problem by embedding the identity of each phone together with its key. (The NSA creates all keys and is trusted by everyone, so this works.) When two phones talk to each other securely, they exchange keys and display the other phone’s identity on a screen. Because the phone is in a secure location, the user now knows who he is talking to, and if the phone displays another organization—as it would if there were a MITM attack in progress—he should hang up.

Zfone, a secure VoIP system, protects against MITM attacks with a short authentication string. After two Zfone terminals exchange keys, both computers display a four-character string. The users are supposed to manually verify that both strings are the same—”my screen says 5C19; what does yours say?”—to ensure that the phones are communicating directly with each other and not with an MITM. The AT&T TSD-3600 worked similarly.

This sort of protection is embedded in SSL, although no one uses it. As it is normally used, SSL provides an encrypted communications link to whoever is at the other end: bank and phishing site alike. And the better phishing sites create valid SSL connections, so as to more effectively fool users. But if the user wanted to, he could manually check the SSL certificate to see if it was issued to “National Bank of Trustworthiness” or “Two Guys With a Computer in Nigeria.”

No one does, though, because you have to both remember and be willing to do the work. (The browsers could make this easier if they wanted to, but they don’t seem to want to.) In the real world, you can easily tell a branch of your bank from a money changer on a street corner. But on the internet, a phishing site can be easily made to look like your bank’s legitimate website. Any method of telling the two apart takes work. And that’s the first step to fooling you with a MITM attack.

Man-in-the-middle isn’t new, and it doesn’t have to be technological. But the internet makes the attacks easier and more powerful, and that’s not going to change anytime soon.

This essay originally appeared on Wired.com.

Posted on July 15, 2008 at 6:47 AM • View Comments

LifeLock and Identity Theft

LifeLock, one of the companies that offers identity-theft protection in the United States, has been taking quite a beating recently. They’re being sued by credit bureaus, competitors and lawyers in several states that are launching class action lawsuits. And the stories in the media … it’s like a piranha feeding frenzy.

There are also a lot of errors and misconceptions. With its aggressive advertising campaign and a CEO who publishes his Social Security number and dares people to steal his identity—Todd Davis, 457-55-5462—LifeLock is a company that’s easy to hate. But the company’s story has some interesting security lessons, and it’s worth understanding in some detail.

In December 2003, as part of the Fair and Accurate Credit Transactions Act, or Facta, credit bureaus were forced to allow you to put a fraud alert on their credit reports, requiring lenders to verify your identity before issuing a credit card in your name. This alert is temporary, and expires after 90 days. Several companies have sprung up—LifeLock, Debix, LoudSiren, TrustedID—that automatically renew these alerts and effectively make them permanent.

This service pisses off the credit bureaus and their financial customers. The reason lenders don’t routinely verify your identity before issuing you credit is that it takes time, costs money and is one more hurdle between you and another credit card. (Buy, buy, buy—it’s the American way.) So in the eyes of credit bureaus, LifeLock’s customers are inferior goods; selling their data isn’t as valuable. LifeLock also opts its customers out of pre-approved credit card offers, further making them less valuable in the eyes of credit bureaus.

And, so began a smear campaign on the part of the credit bureaus. You can read their points of view in this New York Times article, written by a reporter who didn’t do much more than regurgitate their talking points. And the class action lawsuits have piled on, accusing LifeLock of deceptive business practices, fraudulent advertising and so on. The biggest smear is that LifeLock didn’t even protect Todd Davis, and that his identity was allegedly stolen.

It wasn’t. Someone in Texas used Davis’s SSN to get a $500 advance against his paycheck. It worked because the loan operation didn’t check with any of the credit bureaus before approving the loan—perfectly reasonable for an amount this small. The payday-loan operation called Davis to collect, and LifeLock cleared up the problem. His credit report remains spotless.

The Experian credit bureau’s lawsuit basically claims that fraud alerts are only for people who have been victims of identity theft. This seems spurious; the text of the law states that anyone “who asserts a good faith suspicion that the consumer has been or is about to become a victim of fraud or related crime” can request a fraud alert. It seems to me that includes anybody who has ever received one of those notices about their financial details being lost or stolen, which is everybody.

As to deceptive business practices and fraudulent advertising—those just seem like class action lawyers piling on. LifeLock’s aggressive fear-based marketing doesn’t seem any worse than a lot of other similar advertising campaigns. My guess is that the class action lawsuits won’t go anywhere.

In reality, forcing lenders to verify identity before issuing credit is exactly the sort of thing we need to do to fight identity theft. Basically, there are two ways to deal with identity theft: Make personal information harder to steal, and make stolen personal information harder to use. We all know the former doesn’t work, so that leaves the latter. If Congress wanted to solve the problem for real, one of the things it would do is make fraud alerts permanent for everybody. But the credit industry’s lobbyists would never allow that.

LifeLock does a bunch of other clever things. They monitor the national address database, and alert you if your address changes. They look for your credit and debit card numbers on hacker and criminal websites and such, and assist you in getting a new number if they see it. They have a million-dollar service guarantee—for complicated legal reasons, they can’t call it insurance—to help you recover if your identity is ever stolen.

But even with all of this, I am not a LifeLock customer. At $120 a year, it’s just not worth it. You wouldn’t know it from the press attention, but dealing with identity theft has become easier and more routine. Sure, it’s a pervasive problem. The Federal Trade Commission reported that 8.3 million Americans were identity-theft victims in 2005. But that includes things like someone stealing your credit card and using it, something that rarely costs you any money and that LifeLock doesn’t protect against. New account fraud is much less common, affecting 1.8 million Americans per year, or 0.8 percent of the adult population. The FTC hasn’t published detailed numbers for 2006 or 2007, but the rate seems to be declining.

New card fraud is also not very damaging. The median amount of fraud the thief commits is $1,350, but you’re not liable for that. Some spectacularly horrible identity-theft stories notwithstanding, the financial industry is pretty good at quickly cleaning up the mess. The victim’s median out-of-pocket cost for new account fraud is only $40, plus ten hours of grief to clean up the problem. Even assuming your time is worth $100 an hour, LifeLock isn’t worth more than $8 a year.

And it’s hard to get any data on how effective LifeLock really is. They’ve been in business three years and have about a million customers, but most of them have joined up in the last year. They’ve paid out on their service guarantee 113 times, but a lot of those were for things that happened before their customers became customers. (It was easier to pay than argue, I assume.) But they don’t know how often the fraud alerts actually catch an identity thief in the act. My guess is that it’s less than the 0.8 percent fraud rate above.

LifeLock’s business model is based more on the fear of identity theft than the actual risk.

It’s pretty ironic of the credit bureaus to attack LifeLock on its marketing practices, since they know all about profiting from the fear of identity theft. Facta also forced the credit bureaus to give Americans a free credit report once a year upon request. Through deceptive marketing techniques, they’ve turned this requirement into a multimillion-dollar business.

Get LifeLock if you want, or one of its competitors if you prefer. But remember that you can do most of what these companies do yourself. You can put a fraud alert on your own account, but you have to remember to renew it every three months. You can also put a credit freeze on your account, which is more work for the average consumer but more effective if you’re a privacy wonk—and the rules differ by state. And maybe someday Congress will do the right thing and put LifeLock out of business by forcing lenders to verify identity every time they issue credit in someone’s name.

This essay originally appeared in Wired.com.

Posted on June 17, 2008 at 6:51 AM • View Comments

Clever Micro-Deposit Scam

This is clever:

Michael Largent, 22, of Plumas Lake, California, allegedly exploited a loophole in a common procedure both companies follow when a customer links his brokerage account to a bank account for the first time. To verify that the account number and routing information is correct, the brokerages automatically send small “micro-deposits” of between two cents to one dollar to the account, and ask the customer to verify that they’ve received it.

Largent allegedly used an automated script to open 58,000 online brokerage accounts, linking each of them to a handful of online bank accounts, and accumulating thousands of dollars in micro-deposits.

Posted on June 5, 2008 at 1:25 PM • View Comments

Identity Theft from the Dead

List of deaths, intended to prevent identity theft, is used for identity theft:

Ironically, the government produces the monthly Death Index so that banks and other lenders can prevent people from applying for credit using a dead person’s information—the index is made public by the Department of Commerce under the Freedom of Information Act. The caper Kirkland’s accused of mastering apparently exploits a loophole, by taking over accounts that are already open.

Posted on April 25, 2008 at 6:01 AM • View Comments

Fraud Due to a Credit Card Breach

This sort of story is nothing new:

Hannaford said credit and debit card numbers were stolen during the card authorization process and about 4.2 million unique account numbers were exposed.

But it’s rare that we see statistics about the actual risk of fraud:

The company is aware of about 1,800 cases of fraud reported so far relating to the breach.

And this is interesting:

“Visa and MasterCard have stipulated in their contracts with retailers that they will not divulge who the source is when a data breach occurs,” Spitzer said. “We’ve been engaged in a dialogue for a couple years now about changing this rule…. Without knowing who the retailer is that caused the breach, it’s hard for banks to conduct a good investigation on behalf of their consumers. And it’s a problem for consumers as well, because if they know which retailer is responsible, they can rule themselves out for being at risk if they don’t shop at that retailer.”

Posted on March 21, 2008 at 6:39 AM • View Comments

The Nugache Worm/Botnet

I’ve already written about the Storm worm, and how it represents a new generation of worm/botnets. And Scott Berinato has written an excellent article about the Gozi worm, another new-generation worm/botnet.

This article is about yet another new-generation worm-botnet: Nugache. Dave Dittrich thinks this is the most advanced worm/botnet yet:

But this new piece of malware, which came to be known as Nugache, was a game-changer. With no C&C server to target, bots capable of sending encrypted packets and the possibility of any peer on the network suddenly becoming the de facto leader of the botnet, Nugache, Dittrich knew, would be virtually impossible to stop.

[…]

Nugache, and its more famous cousin, the Storm Trojan, are not simply the next step in the evolution of malware. They represent a major step forward in both the quality of software that malware authors are producing and in the sophistication of their tactics. Although they’re often referred to as worms, Storm and Nugache are actually Trojans. The Storm creator, for example, sends out millions of spam messages on a semi-regular basis, each containing a link to content on some remote server, normally disguised in a fake pitch for a penny stock, Viagra or relief for victims of a recent natural disaster. When a user clicks on the link, the attacker’s server installs the Storm Trojan on the user’s PC and it’s off and running.

Various worms, viruses, bots and Trojans over the years have had one or two of the features that Storm, Nugache, Rbot and other such programs possess, but none has approached the breadth and depth of their feature sets. Rbot, for example, has more than 100 features that users can choose from when compiling the bot. This means that two different bots compiled from an identical source could have nearly identical feature sets, yet look completely different to an antivirus engine.

[…]

As scary as Storm and Nugache are, the scarier thing is that they represent just the tip of the iceberg. Experts say that there are several malware groups out there right now that are writing custom Trojans, rootkits and attack toolkits to the specifications of their customers. The customers are in turn using the malware not to build worldwide botnets a la Storm, but to attack small slices of a certain industry, such as financial services or health care.

Rizo, a variant of the venerable Rbot, is the poster child for this kind of attack. A Trojan in the style of Nugache and Storm, Rizo has been modified a number of times to meet the requirements of various different attack scenarios. Within the course of a few weeks, different versions of Rizo were used to attack customers of several different banks in South America. Once installed on a user’s PC, it monitors Internet activity and gathers login credentials for online banking sites, which it then sends back to the attacker. It’s standard behavior for these kinds of Trojans, but the amount of specificity and customization involved in the code and the ways in which the author changed it over time are what have researchers worried.

[…]

“I’m pretty sure that there are tactics being shared between the Nugache and Storm authors,” Dittrich said. “There’s a direct lineage from Sdbot to Rbot to Mytob to Bancos. These guys can just sell the Web front-end to these things and the customers can pick their options and then just hit go.”

See also: “Command and control structures in malware: From Handler/Agent to P2P,” by Dave Dittrich and Sven Dietrich, USENIX ;login:, vol. 32, no. 6, December 2007, and “Analysis of the Storm and Nugache Trojans: P2P is here,” Sam Stover, Dave Dittrich, John Hernandez, and Sven Dietrich, USENIX ;login:, vol. 32, no. 6, December 2007. The second link is available to USENIX members only, unfortunately.

Posted on December 31, 2007 at 7:19 AM • View Comments

UK's Privacy Chernobyl

I didn’t write about this story at first because we’ve seen it so many times before: a disk with lots of personal information is lost. Encryption is the simple and obvious solution, and that’s the end of it.

But the UK’s loss of 25 million child benefit records—including dates of birth, addresses, bank account information, and national insurance numbers—is turning into a privacy disaster, threatening to derail plans for a national ID card.

Why is it such a big deal? Certainly the scope: 40% of the British population. Also the data: bank account details; plus information about children. There’s already a larger debate on the issue of a database on kids that this feeds into. And it’s a demonstration of government incompetence (think Hurricane Katrina).

In any case, this issue isn’t going away anytime soon. Prime Minister Gordon Brown has apologized. The head of the Revenue and Customs office has resigned. More is certainly coming.

And this is an easy security problem to solve! Disk and file encryption software is cheap, easy to use, and effective.

Posted on November 26, 2007 at 1:15 PM • View Comments

Identity Theft Study

Interesting study: “Identity Fraud Trends and Patterns: Building a Data-Based Foundation for Proactive Enforcement,” October 2007. It’s long, but at least read the executive summary. Or, even shorter, this Associated Press story:

Researchers reviewed 517 cases closed by the Secret Service between 2000 and 2006. Two-thirds of the cases were concentrated in the Northeast and South and there were 933 defendants. The Federal Trade Commission has said about 3 million Americans have their identities stolen annually.

The study found that 42.5 percent of offenders were between the ages of 25 and 34. Another 18 percent were between the ages of 18 and 24. Two-thirds of the identity thieves were male.

Nearly a quarter of the offenders were born outside the United States.

Eighty percent of the cases involved an offender working solo or with a single partner, the report found.

While identity thieves used a wide combination of methods, fewer than 20 percent of the crimes involved the Internet. The most frequently used non-technological method was the rerouting of mail through change of address cards. Other prevalent non-technological methods were mail theft and dumpster diving.

Of the 933 offenders, 609 said they initiated their crime by stealing fragments of personal identifying information, as opposed to stealing entire documents, such as bank cards or driver’s licenses.

Most of the offenses were committed by non-employees who victimized strangers. Employee insiders were the offenders in just one-third of the 517 cases. When an employee did commit identity theft, the offenders were employed in a retail business in two out of every five instances, the report said. Stores, gas stations, car dealerships, casinos, restaurants, hotels, doctors and hospitals were all considered retail operations in the study.

In about a fifth of the cases, the employee worked in the financial services industry.

Posted on November 7, 2007 at 7:36 AM • View Comments

Synthetic Identity Theft

Synthetic identity theft is poised to become a bigger problem than regular identity theft:

Unlike traditional identity thieves, who purloin people’s information to get loans or make purchases, fraudsters like Mr. Rose mix legitimate and phony data to create synthetic identities. This kind of fraud doesn’t usually directly affect consumers. The big losers are banks, which get stuck with loan defaults and unpaid credit-card bills that identity thieves leave behind.

Actually, real people do get harmed:

The men paired fake names with Social Security numbers of real people. Adam Gregory, the purported Las Vegas resident, had the Social Security number of a real California resident.

The conspirators needed addresses for their synthetic identities and for a dozen or so shell companies that helped to facilitate the scam. Eventually they rented 200-odd apartments in 14 states. They kept binders of data in their Phoenix headquarters to keep the details straight.

The duo acquired business licenses, usually online, for the dummy businesses. A few had real offices with furniture; others rented “virtual” office space. After Messrs. Rose and Newton triggered the credit bureaus to set up no-hit files for their synthetic identities, their shell companies fed false data to credit bureaus.

More here.

Posted on November 5, 2007 at 6:14 AM • View Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.