Entries Tagged "malware"

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"Evil Maid" Attacks on Encrypted Hard Drives

Earlier this month, Joanna Rutkowska implemented the “evil maid” attack against TrueCrypt. The same kind of attack should work against any whole-disk encryption, including PGP Disk and BitLocker. Basically, the attack works like this:

Step 1: Attacker gains access to your shut-down computer and boots it from a separate volume. The attacker writes a hacked bootloader onto your system, then shuts it down.

Step 2: You boot your computer using the attacker’s hacked bootloader, entering your encryption key. Once the disk is unlocked, the hacked bootloader does its mischief. It might install malware to capture the key and send it over the Internet somewhere, or store it in some location on the disk to be retrieved later, or whatever.

You can see why it’s called the “evil maid” attack; a likely scenario is that you leave your encrypted computer in your hotel room when you go out to dinner, and the maid sneaks in and installs the hacked bootloader. The same maid could even sneak back the next night and erase any traces of her actions.

This attack exploits the same basic vulnerability as the “Cold Boot” attack from last year, and the “Stoned Boot” attack from earlier this year, and there’s no real defense to this sort of thing. As soon as you give up physical control of your computer, all bets are off.

Similar hardware-based attacks were among the main reasons why Symantec’s CTO Mark Bregman was recently advised by “three-letter agencies in the US Government” to use separate laptop and mobile device when traveling to China, citing potential hardware-based compromise.

PGP sums it up in their blog.

No security product on the market today can protect you if the underlying computer has been compromised by malware with root level administrative privileges. That said, there exists well-understood common sense defenses against “Cold Boot,” “Stoned Boot” “Evil Maid,” and many other attacks yet to be named and publicized.

The defenses are basically two-factor authentication: a token you don’t leave in your hotel room for the maid to find and use. The maid could still corrupt the machine, but it’s more work than just storing the password for later use. Putting your data on a thumb drive and taking it with you doesn’t work; when you return you’re plugging your thumb into a corrupted machine.

The real defense here is trusted boot, something Trusted Computing is supposed to enable. But Trusted Computing has its own problems, which is why we haven’t seen anything out of Microsoft in the seven-plus years they have been working on it (I wrote this in 2002 about what they then called Palladium).

In the meantime, people who encrypt their hard drives, or partitions on their hard drives, have to realize that the encryption gives them less protection than they probably believe. It protects against someone confiscating or stealing their computer and then trying to get at the data. It does not protect against an attacker who has access to your computer over a period of time during which you use it, too.

EDITED TO ADD (10/23): A few readers have pointed out that BitLocker, the one thing that has come out of Microsoft’s Trusted Computing initiative in the seven-plus years they’ve been working on it, can prevent these sorts of attacks if the computer has a TPM module, version 1.2 or later, on the motherboard. (Note: Not all computers do.) I actually knew that; I just didn’t remember it.

EDITED TO ADD (11/12): Peter Kleissner’s Stoned Boot attacks on TrueCrypt.

EDITED TO ADD (12/9): A similar attack is possible against BitLocker with a TPM.

Posted on October 23, 2009 at 6:43 AM • View Comments

David Dittrich on Criminal Malware

Good essay: “Malware to crimeware: How far have they gone, and how do we catch up?” ;login:, August 2009:

I have surveyed over a decade of advances in delivery of malware. Over this period, attackers have shifted to using complex, multi-phase attacks based on
subtle social engineering tactics, advanced cyptographic techniques to defeat takeover and analysis, and highly targeted attacks that are intended to fly below the radar of
current technical defenses. I will show how malicious technology combined with social manipulation is used against us and conclude that this understanding might even help us design our own combination of technical and social mechanisms to better protect us.

Posted on October 13, 2009 at 7:15 AM • View Comments

Malware that Forges Bank Statements

This is brilliant:

The sophisticated hack uses a Trojan horse program installed on the victim’s machine that alters html coding before it’s displayed in the user’s browser, to either erase evidence of a money transfer transaction entirely from a bank statement, or alter the amount of money transfers and balances.

Another article.

If there’s a moral here, it’s that banks can’t rely on the customer to detect fraud. But we already knew that.

Posted on October 6, 2009 at 6:40 AM • View Comments

Hacking Two-Factor Authentication

Back in 2005, I wrote about the failure of two-factor authentication to mitigate banking fraud:

Here are two new active attacks we’re starting to see:

  • Man-in-the-Middle attack. An attacker puts up a fake bank website and entices user to that website. User types in his password, and the attacker in turn uses it to access the bank’s real website. Done right, the user will never realize that he isn’t at the bank’s website. Then the attacker either disconnects the user and makes any fraudulent transactions he wants, or passes along the user’s banking transactions while making his own transactions at the same time.
  • Trojan attack. Attacker gets Trojan installed on user’s computer. When user logs into his bank’s website, the attacker piggybacks on that session via the Trojan to make any fraudulent transaction he wants.

See how two-factor authentication doesn’t solve anything? In the first case, the attacker can pass the ever-changing part of the password to the bank along with the never-changing part. And in the second case, the attacker is relying on the user to log in.

Here’s an example:

The theft happened despite Ferma’s use of a one-time password, a six-digit code issued by a small electronic device every 30 or 60 seconds. Online thieves have adapted to this additional security by creating special programs—real-time Trojan horses—that can issue transactions to a bank while the account holder is online, turning the one-time password into a weak link in the financial security chain. “I think it’s a broken model,” Ferrari says.

Of course it’s a broken model. We have to stop trying to authenticate the person; instead, we need to authenticate the transaction:

One way to think about this is that two-factor authentication solves security problems involving authentication. The current wave of attacks against financial systems are not exploiting vulnerabilities in the authentication system, so two-factor authentication doesn’t help.

Security is always an arms race, and you could argue that this situation is simply the cost of treading water. The problem with this reasoning is it ignores countermeasures that permanently reduce fraud. By concentrating on authenticating the individual rather than authenticating the transaction, banks are forced to defend against criminal tactics rather than the crime itself.

Credit cards are a perfect example. Notice how little attention is paid to cardholder authentication. Clerks barely check signatures. People use their cards over the phone and on the Internet, where the card’s existence isn’t even verified. The credit card companies spend their security dollar authenticating the transaction, not the cardholder.

More on mitigating identity theft.

Posted on September 22, 2009 at 6:39 AM • View Comments

The Global Illicit Economy

Interesting video:

A new class of global actors is playing an increasingly important role in globalization: smugglers, warlords, guerrillas, terrorists, gangs, and bandits of all stripes. Since the end of the Cold War, the global illicit economy has consistently grown at twice the rate of the licit global economy. Increasingly, illicit actors will represent not just an economic but a political force. As globalization hollows out traditional nation-states, what will fill the power vacuum in slums and hinterlands will be informal non-state governance structures. These zones will be globally connected, effectively run by local gangs, religious leaders, or quasi-tribal organizations—organizations that will govern without aspiring to statehood.

Malware is one of Nils Gilman’s examples, at about the nine-minute mark.

The seven rules of the illicit global economy (he seems to use “illicit” and “deviant” interchangeably in the talk):

  1. Perfectly legitimate forms of demand can produce perfectly deviant forms of supply.
  2. Uneven global regulatory structures create arbitrage opportunities for deviant entrepreneurs.
  3. Pathways for legitimate globalization are always also pathways for deviant globalization.
  4. Once a deviant industry professionalizes, crackdowns merely promote innovation.
  5. States themselves undermine the distinction between legitimate and deviant economics.
  6. Unchecked, deviant entrepreneurs will overtake the legitimate economy.
  7. Deviant globalization presents an existential challenge to state legitimacy.

Posted on September 8, 2009 at 7:12 AM • View Comments

Small Business Identity Theft and Fraud

The sorts of crimes we’ve been seeing perpetrated against individuals are starting to be perpetrated against small businesses:

In July, a school district near Pittsburgh sued to recover $700,000 taken from it. In May, a Texas company was robbed of $1.2 million. An electronics testing firm in Baton Rouge, La., said it was bilked of nearly $100,000.

In many cases, the advisory warned, the scammers infiltrate companies in a similar fashion: They send a targeted e-mail to the company’s controller or treasurer, a message that contains either a virus-laden attachment or a link that—when opened—surreptitiously installs malicious software designed to steal passwords. Armed with those credentials, the crooks then initiate a series of wire transfers, usually in increments of less than $10,000 to avoid banks’ anti-money-laundering reporting requirements.

The alert states that these scams typically rely on help from “money mules”—willing or unwitting individuals in the United States—often hired by the criminals via popular Internet job boards. Once enlisted, the mules are instructed to set up bank accounts, withdraw the fraudulent deposits and then wire the money to fraudsters, the majority of which are in Eastern Europe, according to the advisory.

This has the potential to grow into a very big problem. Even worse:

Businesses do not enjoy the same legal protections as consumers when banking online. Consumers typically have up to 60 days from the receipt of a monthly statement to dispute any unauthorized charges.

In contrast, companies that bank online are regulated under the Uniform Commercial Code, which holds that commercial banking customers have roughly two business days to spot and dispute unauthorized activity if they want to hold out any hope of recovering unauthorized transfers from their accounts.

And, of course, the security externality means that the banks care much less:

“The banks spend a lot of money on protecting consumer customers because they owe money if the consumer loses money,” Litan said. “But the banks don’t spend the same resources on the corporate accounts because they don’t have to refund the corporate losses.”

Posted on August 26, 2009 at 5:46 AM • View Comments

North Korean Cyberattacks

To hear the media tell it, the United States suffered a major cyberattack last week. Stories were everywhere. "Cyber Blitz hits U.S., Korea" was the headline in Thursday’s Wall Street Journal. North Korea was blamed.

Where were you when North Korea attacked America? Did you feel the fury of North Korea’s armies? Were you fearful for your country? Or did your resolve strengthen, knowing that we would defend our homeland bravely and valiantly?

My guess is that you didn’t even notice, that—if you didn’t open a newspaper or read a news website—you had no idea anything was happening. Sure, a few government websites were knocked out, but that’s not alarming or even uncommon. Other government websites were attacked but defended themselves, the sort of thing that happens all the time. If this is what an international cyberattack looks like, it hardly seems worth worrying about at all.

Politically motivated cyber attacks are nothing new. We’ve seen UK vs. Ireland. Israel vs. the Arab states. Russia vs. several former Soviet Republics. India vs. Pakistan, especially after the nuclear bomb tests in 1998. China vs. the United States, especially in 2001 when a U.S. spy plane collided with a Chinese fighter jet. And so on and so on.

The big one happened in 2007, when the government of Estonia was attacked in cyberspace following a diplomatic incident with Russia about the relocation of a Soviet World War II memorial. The networks of many Estonian organizations, including the Estonian parliament, banks, ministries, newspapers and broadcasters, were attacked and—in many cases—shut down. Estonia was quick to blame Russia, which was equally quick to deny any involvement.

It was hyped as the first cyberwar, but after two years there is still no evidence that the Russian government was involved. Though Russian hackers were indisputably the major instigators of the attack, the only individuals positively identified have been young ethnic Russians living inside Estonia, who were angry over the statue incident.

Poke at any of these international incidents, and what you find are kids playing politics. Last Wednesday, South Korea’s National Intelligence Service admitted that it didn’t actually know that North Korea was behind the attacks: "North Korea or North Korean sympathizers in the South" was what it said. Once again, it’ll be kids playing politics.

This isn’t to say that cyberattacks by governments aren’t an issue, or that cyberwar is something to be ignored. The constant attacks by Chinese nationals against U.S. networks may not be government-sponsored, but it’s pretty clear that they’re tacitly government-approved. Criminals, from lone hackers to organized crime syndicates, attack networks all the time. And war expands to fill every possible theater: land, sea, air, space, and now cyberspace. But cyberterrorism is nothing more than a media invention designed to scare people. And for there to be a cyberwar, there first needs to be a war.

Israel is currently considering attacking Iran in cyberspace, for example. If it tries, it’ll discover that attacking computer networks is an inconvenience to the nuclear facilities it’s targeting, but doesn’t begin to substitute for bombing them.

In May, President Obama gave a major speech on cybersecurity. He was right when he said that cybersecurity is a national security issue, and that the government needs to step up and do more to prevent cyberattacks. But he couldn’t resist hyping the threat with scare stories: "In one of the most serious cyber incidents to date against our military networks, several thousand computers were infected last year by malicious software—malware," he said. What he didn’t add was that those infections occurred because the Air Force couldn’t be bothered to keep its patches up to date.

This is the face of cyberwar: easily preventable attacks that, even when they succeed, only a few people notice. Even this current incident is turning out to be a sloppily modified five-year-old worm that no modern network should still be vulnerable to.

Securing our networks doesn’t require some secret advanced NSA technology. It’s the boring network security administration stuff we already know how to do: keep your patches up to date, install good anti-malware software, correctly configure your firewalls and intrusion-detection systems, monitor your networks. And while some government and corporate networks do a pretty good job at this, others fail again and again.

Enough of the hype and the bluster. The news isn’t the attacks, but that some networks had security lousy enough to be vulnerable to them.

This essay originally appeared on the Minnesota Public Radio website.

Posted on July 13, 2009 at 11:45 AM • View Comments

Making an Operating System Virus Free

Commenting on Google’s claim that Chrome was designed to be virus-free, I said:

Bruce Schneier, the chief security technology officer at BT, scoffed at Google’s promise. “It’s an idiotic claim,” Schneier wrote in an e-mail. “It was mathematically proved decades ago that it is impossible—not an engineering impossibility, not technologically impossible, but the 2+2=3 kind of impossible—to create an operating system that is immune to viruses.”

What I was referring to, although I couldn’t think of his name at the time, was Fred Cohen’s 1986 Ph.D. thesis where he proved that it was impossible to create a virus-checking program that was perfect. That is, it is always possible to write a virus that any virus-checking program will not detect.

This reaction to my comment is accurate:

That seems to us like he’s picking on the semantics of Google’s statement just a bit. Google says that users “won’t have to deal with viruses,” and Schneier is noting that it’s simply not possible to create an OS that can’t be taken down by malware. While that may be the case, it’s likely that Chrome OS is going to be arguably more secure than the other consumer operating systems currently in use today. In fact, we didn’t take Google’s statement to mean that Chrome OS couldn’t get a virus EVER; we just figured they meant it was a lot harder to get one on their new OS – didn’t you?

When I said that I had not seen Google’s statement. I was responding to what the reporter was telling me on the phone. So yes, I jumped on the reporter’s claim about Google’s claim. I did try to temper my comment:

Redesigning an operating system from scratch, “[taking] security into account all the way up and down,” could make for a more secure OS than ones that have been developed so far, Schneier said. But that’s different from Google’s promise that users won’t have to deal with viruses or malware, he added.

To summarize, there is a lot that can be done in an OS to reduce the threat of viruses and other malware. If the Chrome team started from scratch and took security seriously all through the design and development process, they have to potential to develop something really secure. But I don’t know if they did.

Posted on July 10, 2009 at 9:44 AM • View Comments

Malware Steals ATM Data

One of the risks of using a commercial OS for embedded systems like ATMs: it’s easier to write malware against it:

The report does not detail how the ATMs are infected, but it seems likely that the malware is encoded on a card that can be inserted in an ATM card reader to mount a buffer overflow attack. The machine is compromised by replacing the isadmin.exe file to infect the system.

The malicious isadmin.exe program then uses the Windows API to install the functional attack code by replacing a system file called lsass.exe in the C:WINDOWS directory.

Once the malicious lsass.exe program is installed, it collects users account numbers and PIN codes and waits for a human controller to insert a specially crafted control card to take over the ATM.

After the ATM is put under control of a human attacker, they can perform various functions, including harvesting the purloined data or even ejecting the cash box.

EDITED TO ADD (6/14): Seems like the story I quoted was jumping to conclusions. The actual report says “the malware is installed and activated through a dropper file (a file that an attacker can use to deploy tools onto a compromised system) by the name of isadmin.exe,” which doesn’t really sound like it’s referring to a buffer overflow attack carried out through a card emulator. Also, The Register says “[the] malicious programs can be installed only by people with physical access to the machines, making some level of insider cooperation necessary.”

Posted on June 10, 2009 at 1:51 PM • View Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.