Entries Tagged "network security"

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WiFi Driver Attack

In this attack, you can seize control of someone’s computer using his WiFi interface, even if he’s not connected to a network.

The two researchers used an open-source 802.11 hacking tool called LORCON (Loss of Radio Connectivity) to throw an extremely large number of wireless packets at different wireless cards. Hackers use this technique, called fuzzing, to see if they can cause programs to fail, or perhaps even run unauthorized software when they are bombarded with unexpected data.

Using tools like LORCON, Maynor and Ellch were able to discover many examples of wireless device driver flaws, including one that allowed them to take over a laptop by exploiting a bug in an 802.11 wireless driver. They also examined other networking technologies including Bluetooth, Ev-Do (EVolution-Data Only), and HSDPA (High Speed Downlink Packet Access).

The two researchers declined to disclose the specific details of their attack before the August 2 presentation, but they described it in dramatic terms.

“This would be the digital equivalent of a drive-by shooting,” said Maynor. An attacker could exploit this flaw by simply sitting in a public space and waiting for the right type of machine to come into range.

The victim would not even need to connect to a network for the attack to work.

No details yet. The researchers are presenting their results at BlackHat on August 2.

Posted on July 6, 2006 at 1:52 PM • View Comments

Who Owns Your Computer?

When technology serves its owners, it is liberating. When it is designed to serve others, over the owner’s objection, it is oppressive. There’s a battle raging on your computer right now—one that pits you against worms and viruses, Trojans, spyware, automatic update features and digital rights management technologies. It’s the battle to determine who owns your computer.

You own your computer, of course. You bought it. You paid for it. But how much control do you really have over what happens on your machine? Technically you might have bought the hardware and software, but you have less control over what it’s doing behind the scenes.

Using the hacker sense of the term, your computer is “owned” by other people.

It used to be that only malicious hackers were trying to own your computers. Whether through worms, viruses, Trojans or other means, they would try to install some kind of remote-control program onto your system. Then they’d use your computers to sniff passwords, make fraudulent bank transactions, send spam, initiate phishing attacks and so on. Estimates are that somewhere between hundreds of thousands and millions of computers are members of remotely controlled “bot” networks. Owned.

Now, things are not so simple. There are all sorts of interests vying for control of your computer. There are media companies that want to control what you can do with the music and videos they sell you. There are companies that use software as a conduit to collect marketing information, deliver advertising or do whatever it is their real owners require. And there are software companies that are trying to make money by pleasing not only their customers, but other companies they ally themselves with. All these companies want to own your computer.

Some examples:

  • Entertainment software: In October 2005, it emerged that Sony had distributed a rootkit with several music CDs—the same kind of software that crackers use to own people’s computers. This rootkit secretly installed itself when the music CD was played on a computer. Its purpose was to prevent people from doing things with the music that Sony didn’t approve of: It was a DRM system. If the exact same piece of software had been installed secretly by a hacker, this would have been an illegal act. But Sony believed that it had legitimate reasons for wanting to own its customers’ machines.
  • Antivirus: You might have expected your antivirus software to detect Sony’s rootkit. After all, that’s why you bought it. But initially, the security programs sold by Symantec and others did not detect it, because Sony had asked them not to. You might have thought that the software you bought was working for you, but you would have been wrong.
  • Internet services: Hotmail allows you to blacklist certain e-mail addresses, so that mail from them automatically goes into your spam trap. Have you ever tried blocking all that incessant marketing e-mail from Microsoft? You can’t.
  • Application software: Internet Explorer users might have expected the program to incorporate easy-to-use cookie handling and pop-up blockers. After all, other browsers do, and users have found them useful in defending against Internet annoyances. But Microsoft isn’t just selling software to you; it sells Internet advertising as well. It isn’t in the company’s best interest to offer users features that would adversely affect its business partners.
  • Spyware: Spyware is nothing but someone else trying to own your computer. These programs eavesdrop on your behavior and report back to their real owners—sometimes without your knowledge or consent—about your behavior.
  • Internet security: It recently came out that the firewall in Microsoft Vista will ship with half its protections turned off. Microsoft claims that large enterprise users demanded this default configuration, but that makes no sense. It’s far more likely that Microsoft just doesn’t want adware—and DRM spyware—blocked by default.
  • Update: Automatic update features are another way software companies try to own your computer. While they can be useful for improving security, they also require you to trust your software vendor not to disable your computer for nonpayment, breach of contract or other presumed infractions.

Adware, software-as-a-service and Google Desktop search are all examples of some other company trying to own your computer. And Trusted Computing will only make the problem worse.

There is an inherent insecurity to technologies that try to own people’s computers: They allow individuals other than the computers’ legitimate owners to enforce policy on those machines. These systems invite attackers to assume the role of the third party and turn a user’s device against him.

Remember the Sony story: The most insecure feature in that DRM system was a cloaking mechanism that gave the rootkit control over whether you could see it executing or spot its files on your hard disk. By taking ownership away from you, it reduced your security.

If left to grow, these external control systems will fundamentally change your relationship with your computer. They will make your computer much less useful by letting corporations limit what you can do with it. They will make your computer much less reliable because you will no longer have control of what is running on your machine, what it does, and how the various software components interact. At the extreme, they will transform your computer into a glorified boob tube.

You can fight back against this trend by only using software that respects your boundaries. Boycott companies that don’t honestly serve their customers, that don’t disclose their alliances, that treat users like marketing assets. Use open-source software—software created and owned by users, with no hidden agendas, no secret alliances and no back-room marketing deals.

Just because computers were a liberating force in the past doesn’t mean they will be in the future. There is enormous political and economic power behind the idea that you shouldn’t truly own your computer or your software, despite having paid for it.

This essay originally appeared on Wired.com.

EDITED TO ADD (5/5): Commentary. It seems that some of my examples were not very good. I’ll come up with other ones for the Crypto-Gram version.

Posted on May 4, 2006 at 7:13 AM • View Comments

Triple-DES Upgrade Adding Insecurities?

It’s a provocative headline: “Triple DES Upgrades May Introduce New ATM Vulnerabilities.” Basically, at the same time they’re upgrading their encryption to triple-DES, they’re also moving the communications links from dedicated lines to the Internet. And while the protocol encrypts PINs, it doesn’t encrypt any of the other information, such as card numbers and expiration dates.

So it’s the move from dedicated lines to the Internet that’s adding the insecurities.

Posted on April 17, 2006 at 6:48 AM • View Comments

VOIP Encryption

There are basically four ways to eavesdrop on a telephone call.

One, you can listen in on another phone extension. This is the method preferred by siblings everywhere. If you have the right access, it’s the easiest. While it doesn’t work for cell phones, cordless phones are vulnerable to a variant of this attack: A radio receiver set to the right frequency can act as another extension.

Two, you can attach some eavesdropping equipment to the wire with a pair of alligator clips. It takes some expertise, but you can do it anywhere along the phone line’s path—even outside the home. This used to be the way the police eavesdropped on your phone line. These days it’s probably most often used by criminals. This method doesn’t work for cell phones, either.

Three, you can eavesdrop at the telephone switch. Modern phone equipment includes the ability for someone to listen in this way. Currently, this is the preferred police method. It works for both land lines and cell phones. You need the right access, but if you can get it, this is probably the most comfortable way to eavesdrop on a particular person.

Four, you can tap the main trunk lines, eavesdrop on the microwave or satellite phone links, etc. It’s hard to eavesdrop on one particular person this way, but it’s easy to listen in on a large chunk of telephone calls. This is the sort of big-budget surveillance that organizations like the National Security Agency do best. They’ve even been known to use submarines to tap undersea phone cables.

That’s basically the entire threat model for traditional phone calls. And when most people think about IP telephony—voice over internet protocol, or VOIP—that’s the threat model they probably have in their heads.

Unfortunately, phone calls from your computer are fundamentally different from phone calls from your telephone. Internet telephony’s threat model is much closer to the threat model for IP-networked computers than the threat model for telephony.

And we already know the threat model for IP. Data packets can be eavesdropped on anywhere along the transmission path. Data packets can be intercepted in the corporate network, by the internet service provider and along the backbone. They can be eavesdropped on by the people or organizations that own those computers, and they can be eavesdropped on by anyone who has successfully hacked into those computers. They can be vacuumed up by nosy hackers, criminals, competitors and governments.

It’s comparable to threat No. 3 above, but with the scope vastly expanded.

My greatest worry is the criminal attacks. We already have seen how clever criminals have become over the past several years at stealing account information and personal data. I can imagine them eavesdropping on attorneys, looking for information with which to blackmail people. I can imagine them eavesdropping on bankers, looking for inside information with which to make stock purchases. I can imagine them stealing account information, hijacking telephone calls, committing identity theft. On the business side, I can see them engaging in industrial espionage and stealing trade secrets. In short, I can imagine them doing all the things they could never have done with the traditional telephone network.

This is why encryption for VOIP is so important. VOIP calls are vulnerable to a variety of threats that traditional telephone calls are not. Encryption is one of the essential security technologies for computer data, and it will go a long way toward securing VOIP.

The last time this sort of thing came up, the U.S. government tried to sell us something called “key escrow.” Basically, the government likes the idea of everyone using encryption, as long as it has a copy of the key. This is an amazingly insecure idea for a number of reasons, mostly boiling down to the fact that when you provide a means of access into a security system, you greatly weaken its security.

A recent case in Greece demonstrated that perfectly: Criminals used a cell-phone eavesdropping mechanism already in place, designed for the police to listen in on phone calls. Had the call system been designed to be secure in the first place, there never would have been a backdoor for the criminals to exploit.

Fortunately, there are many VOIP-encryption products available. Skype has built-in encryption. Phil Zimmermann is releasing Zfone, an easy-to-use open-source product. There’s even a VOIP Security Alliance.

Encryption for IP telephony is important, but it’s not a panacea. Basically, it takes care of threats No. 2 through No. 4, but not threat No. 1. Unfortunately, that’s the biggest threat: eavesdropping at the end points. No amount of IP telephony encryption can prevent a Trojan or worm on your computer—or just a hacker who managed to get access to your machine—from eavesdropping on your phone calls, just as no amount of SSL or e-mail encryption can prevent a Trojan on your computer from eavesdropping—or even modifying—your data.

So, as always, it boils down to this: We need secure computers and secure operating systems even more than we need secure transmission.

This essay originally appeared on Wired.com.

Posted on April 6, 2006 at 5:09 AM • View Comments

More on Port Security

From Defective Yeti:

Sark Defends Port Deal

Sark today sought to quell the growing controversy over his decision to grant the MCP control of several major ports throughout the region.

“I believe that this arrangement with the Master Control Program should go forward,” Sark told reporters aboard Solar Sailer One. He emphasized that security would continued to be handled by Tank and Recognizer programs, with the MCP only be in charge of port operations.

But Dumont, guardian of the I/O towers, voiced skepticism. “I could understand ceding authority over ports 21 and 80,” said Dumont. “But port 443? That’s supposed to be secure!”

The public’s reaction to the plan has also been overwhelmingly negative. “No no no,” said a bit upon hearing the news. “No no no no.” Others were more blunt. “Sark should be de-rezzed for even proposing this,” said Ram, a financial program.

Sark, who has repeatedly denied having ties to the MCP, has insisted that the hand-over go through, and says that he will vigorously resist any effort to block it. But programs such as Yori are equally adamant that the deal be scuttled. “My User,” she said, “have we already forgotten the lessons of 1000222846?”

Posted on February 27, 2006 at 6:12 AM • View Comments

Security in the Cloud

One of the basic philosophies of security is defense in depth: overlapping systems designed to provide security even if one of them fails. An example is a firewall coupled with an intrusion-detection system (IDS). Defense in depth provides security, because there’s no single point of failure and no assumed single vector for attacks.

It is for this reason that a choice between implementing network security in the middle of the network—in the cloud—or at the endpoints is a false dichotomy. No single security system is a panacea, and it’s far better to do both.

This kind of layered security is precisely what we’re seeing develop. Traditionally, security was implemented at the endpoints, because that’s what the user controlled. An organization had no choice but to put its firewalls, IDSs, and anti-virus software inside its network. Today, with the rise of managed security services and other outsourced network services, additional security can be provided inside the cloud.

I’m all in favor of security in the cloud. If we could build a new Internet today from scratch, we would embed a lot of security functionality in the cloud. But even that wouldn’t substitute for security at the endpoints. Defense in depth beats a single point of failure, and security in the cloud is only part of a layered approach.

For example, consider the various network-based e-mail filtering services available. They do a great job of filtering out spam and viruses, but it would be folly to consider them a substitute for anti-virus security on the desktop. Many e-mails are internal only, never entering the cloud at all. Worse, an attacker might open up a message gateway inside the enterprise’s infrastructure. Smart organizations build defense in depth: e-mail filtering inside the cloud plus anti-virus on the desktop.

The same reasoning applies to network-based firewalls and intrusion-prevention systems (IPS). Security would be vastly improved if the major carriers implemented cloud-based solutions, but they’re no substitute for traditional firewalls, IDSs, and IPSs.

This should not be an either/or decision. At Counterpane, for example, we offer cloud services and more traditional network and desktop services. The real trick is making everything work together.

Security is about technology, people, and processes. Regardless of where your security systems are, they’re not going to work unless human experts are paying attention. Real-time monitoring and response is what’s most important; where the equipment goes is secondary.

Security is always a trade-off. Budgets are limited and economic considerations regularly trump security concerns. Traditional security products and services are centered on the internal network, because that’s the target of attack. Compliance focuses on that for the same reason. Security in the cloud is a good addition, but it’s not a replacement for more traditional network and desktop security.

This was published as a “Face-Off” in Network World.

The opposing view is here.

Posted on February 15, 2006 at 8:18 AM • View Comments

Are Port Scans Precursors to Attack?

Interesting research:

Port scans may not be a precursor to hacking efforts, according to conventional wisdom, reports the University of Maryland’s engineering school.

An analysis of quantitative attack data gathered by the university over a two-month period showed that port scans precede attacks only about five percent of the time, said Michel Cukier, a professor in the Centre for Risk and Reliability. In fact, more than half of all attacks aren’t preceded by a scan of any kind, Cukier said.

I agree with Ullrich, who said that the analysis seems too simplistic:

Johannes Ullrich, chief technology officer at the SANS Institute ‘s Internet Storm Center, said that while the design and development of the testbed used for the research appears to be valid, the analysis is too simplistic.

Rather than counting the number of packets in a connection, it’s far more important to look at the content when classifying a connection as a port scan or an attack, Ullrich said.

Often, attacks such as the SQL Slammer worm, which hit in 2003, can be as small as one data packet, he said. A lot of the automated attacks that take place combine port and vulnerability scans and exploit code, according to Ullrich.

As a result, much of what researchers counted as port scans may have actually been attacks, said Ullrich, whose Bethesda, Md.-based organization provides Internet threat-monitoring services.

Posted on December 15, 2005 at 6:38 AM • View Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.