Entries Tagged "computer security"

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What is a Hacker?

A hacker is someone who thinks outside the box. It’s someone who discards conventional wisdom, and does something else instead. It’s someone who looks at the edge and wonders what’s beyond. It’s someone who sees a set of rules and wonders what happens if you don’t follow them. A hacker is someone who experiments with the limitations of systems for intellectual curiosity.

I wrote that last sentence in the year 2000, in my book Secrets and Lies. And I’m sticking to that definition.

This is what else I wrote in Secrets and Lies (pages 43-44):

Hackers are as old as curiosity, although the term itself is modern. Galileo was a hacker. Mme. Curie was one, too. Aristotle wasn’t. (Aristotle had some theoretical proof that women had fewer teeth than men. A hacker would have simply counted his wife’s teeth. A good hacker would have counted his wife’s teeth without her knowing about it, while she was asleep. A good bad hacker might remove some of them, just to prove a point.)

When I was in college, I knew a group similar to hackers: the key freaks. They wanted access, and their goal was to have a key to every lock on campus. They would study lockpicking and learn new techniques, trade maps of the steam tunnels and where they led, and exchange copies of keys with each other. A locked door was a challenge, a personal affront to their ability. These people weren’t out to do damage—stealing stuff wasn’t their objective—although they certainly could have. Their hobby was the power to go anywhere they wanted to.

Remember the phone phreaks of yesteryear, the ones who could whistle into payphones and make free phone calls. Sure, they stole phone service. But it wasn’t like they needed to make eight-hour calls to Manila or McMurdo. And their real work was secret knowledge: The phone network was a vast maze of information. They wanted to know the system better than the designers, and they wanted the ability to modify it to their will. Understanding how the phone system worked—that was the true prize. Other early hackers were ham-radio hobbyists and model-train enthusiasts.

Richard Feynman was a hacker; read any of his books.

Computer hackers follow these evolutionary lines. Or, they are the same genus operating on a new system. Computers, and networks in particular, are the new landscape to be explored. Networks provide the ultimate maze of steam tunnels, where a new hacking technique becomes a key that can open computer after computer. And inside is knowledge, understanding. Access. How things work. Why things work. It’s all out there, waiting to be discovered.

Computers are the perfect playground for hackers. Computers, and computer networks, are vast treasure troves of secret knowledge. The Internet is an immense landscape of undiscovered information. The more you know, the more you can do.

And it should be no surprise that many hackers have focused their skills on computer security. Not only is it often the obstacle between the hacker and knowledge, and therefore something to be defeated, but also the very mindset necessary to be good at security is exactly the same mindset that hackers have: thinking outside the box, breaking the rules, exploring the limitations of a system. The easiest way to break a security system is to figure out what the system’s designers hadn’t thought of: that’s security hacking.

Hackers cheat. And breaking security regularly involves cheating. It’s figuring out a smart card’s RSA key by looking at the power fluctuations, because the designers of the card never realized anyone could do that. It’s self-signing a piece of code, because the signature-verification system didn’t think someone might try that. It’s using a piece of a protocol to break a completely different protocol, because all previous security analysis only looked at protocols individually and not in pairs.

That’s security hacking: breaking a system by thinking differently.

It all sounds criminal: recovering encrypted text, fooling signature algorithms, breaking protocols. But honestly, that’s just the way we security people talk. Hacking isn’t criminal. All the examples two paragraphs above were performed by respected security professionals, and all were presented at security conferences.

I remember one conversation I had at a Crypto conference, early in my career. It was outside amongst the jumbo shrimp, chocolate-covered strawberries, and other delectables. A bunch of us were talking about some cryptographic system, including Brian Snow of the NSA. Someone described an unconventional attack, one that didn’t follow the normal rules of cryptanalysis. I don’t remember any of the details, but I remember my response after hearing the description of the attack.

“That’s cheating,” I said.

Because it was.

I also remember Brian turning to look at me. He didn’t say anything, but his look conveyed everything. “There’s no such thing as cheating in this business.”

Because there isn’t.

Hacking is cheating, and it’s how we get better at security. It’s only after someone invents a new attack that the rest of us can figure out how to defend against it.

For years I have refused to play the semantic “hacker” vs. “cracker” game. There are good hackers and bad hackers, just as there are good electricians and bad electricians. “Hacker” is a mindset and a skill set; what you do with it is a different issue.

And I believe the best computer security experts have the hacker mindset. When I look to hire people, I look for someone who can’t walk into a store without figuring out how to shoplift. I look for someone who can’t test a computer security program without trying to get around it. I look for someone who, when told that things work in a particular way, immediately asks how things stop working if you do something else.

We need these people in security, and we need them on our side. Criminals are always trying to figure out how to break security systems. Field a new system—an ATM, an online banking system, a gambling machine—and criminals will try to make an illegal profit off it. They’ll figure it out eventually, because some hackers are also criminals. But if we have hackers working for us, they’ll figure it out first—and then we can defend ourselves.

It’s our only hope for security in this fast-moving technological world of ours.

This essay appeared in the Summer 2006 issue of 2600.

Posted on September 14, 2006 at 7:13 AMView Comments

Is There Strategic Software?

If you define “critical infrastructure” as “things essential for the functioning of a society and economy,” then software is critical infrastructure. For many companies and individuals, if their computers stop working, they stop working.

It’s a situation that snuck up on us. Everyone knew that the software that flies 747s or targets cruise missiles was critical, but who thought of the airlines’ weight and balance computers, or the operating system running the databases and spreadsheets that determine which cruise missiles get shipped where?

And over the years, common, off-the-shelf, personal- and business-grade software has been used for more and more critical applications. Today we find ourselves in a situation where a well-positioned flaw in Windows, Cisco routers or Apache could seriously affect the economy.

It’s perfectly rational to assume that some programmers—a tiny minority I’m sure—are deliberately adding vulnerabilities and back doors into the code they write. I’m actually kind of amazed that back doors secretly added by the CIA/NSA, MI5, the Chinese, Mossad and others don’t conflict with each other. Even if these groups aren’t infiltrating software companies with back doors, you can be sure they’re scouring products for vulnerabilities they can exploit, if necessary. On the other hand, we’re already living in a world where dozens of new flaws are discovered in common software products weekly, and the economy is humming along. But we’re not talking about this month’s worm from Asia or new phishing software from the Russian mafia—we’re talking national intelligence organizations. “Infowar” is an overhyped term, but the next war will have a cyberspace component, and these organizations wouldn’t be doing their jobs if they weren’t preparing for it.

Marcus is 100 percent correct when he says it’s simply too late to do anything about it. The software industry is international, and no country can start demanding domestic-only software and expect to get anywhere. Nor would that actually solve the problem, which is more about the allegiance of millions of individual programmers than which country they happen to inhabit.

So, what to do? The key here is to remember the real problem: current commercial software practices are not secure enough to reliably detect and delete deliberately inserted malicious code. Once you understand this, you’ll drop the red herring arguments that led to CheckPoint not being able to buy Sourcefire and concentrate on the real solution: defense in depth.

In theory, security software are after-the-fact kludges because the underlying OS and apps are riddled with vulnerabilities. If your software were written properly, you wouldn’t need a firewall—right?

If we were to get serious about critical infrastructure, we’d recognize it’s all critical and start building security software to protect it. We’d build our security based on the principles of safe failure; we’d assume security would fail and make sure it’s OK when it does. We’d use defense in depth and compartmentalization to minimize the effects of failure. Basically, we’d do everything we’re supposed to do now to secure our networks.

It’d be expensive, probably prohibitively so. Maybe it would be easier to continue to ignore the problem, or at least manage geopolitics so that no national military wants to take us down.

This is the second half of a point/counterpoint I did with Marcus Ranum (here’s his half) for the September 2006 issue of Information Security Magazine.

Posted on September 12, 2006 at 10:38 AMView Comments

USBDumper

USBDumper (article is in French; here’s the software) is a cute little utility that silently copies the contents of an inserted USB drive onto the PC. The idea is that you install this piece of software on your computer, or on a public PC, and then you collect the files—some of them personal and confidential—from anyone who plugs their USB drive into that computer. (This blog post talks about a version that downloads a disk image, allowing someone to recover deleted files as well.)

No big deal to anyone who worries about computer security for a living, but probably a rude shock to salespeople, conference presenters, file sharers, and many others who regularly plug their USB drives into strange PCs.

EDITED TO ADD (10/24): USBDumper 2.2 has been released. The webpage includes a number of other useful utilities.

Posted on August 25, 2006 at 6:47 AMView Comments

Malware Distribution Project

In case you needed a comprehensive database of malware.

Malware Distribution Project (MD:Pro) offers developers of security systems and anti-malware products a vast collection of downloadable malware from a secure and reliable source, exclusively for the purposes of analysis, testing, research and development.

Bringing together for the first time a large back-catalogue of malware, computer underground related information and IT security resources under one project, this major new system also contains a large selection of undetected malware, along with an open, collaborative platform, where malware samples can be shared among its members. The database is constantly updated with new files, and maintained to keep it running at an optimum.

There are currently 271712 files in the system.

This isn’t free. You can subscribe at 1,250 euros for a month, or 13,500 euros a year. (There are cheaper packages with less comprehensive access.)

They claim to have a stringent vetting process, ensuring that only legitimate researchers have access to this database:

It should be noted that we are not a malware/VX distribution site, nor do we condone the public spreading and/or distribution of such information, hence we will be vetting our registrants stringently. We do appreciate that this puts a severe restriction on private (individual) malware researchers and enthusiasts with limited or no budget, but we do feel that providing free malware for public research is out of the scope of this project.

EDITED TO ADD (8/8): The hacker group Cult of the Dead Cow also has a malware repository, free and with looser access restrictions.

Posted on August 8, 2006 at 7:56 AMView Comments

Printer Security

At BlackHat last week, Brendan O’Connor warned about the dangers of insecure printers:

“Stop treating them as printers. Treat them as servers, as workstations,” O’Connor said in his presentation on Thursday. Printers should be part of a company’s patch program and be carefully managed, not forgotten by IT and handled by the most junior person on staff, he said.

I remember the L0pht doing work on printer vulnerabilities, and ways to attack networks via the printers, years ago. But the point is still valid and bears repeating: printers are computers, and have vulnerabilities like any other computers.

Once a printer was under his control, O’Connor said he would be able to use it to map an organization’s internal network—a situation that could help stage further attacks. The breach gave him access to any of the information printed, copied or faxed from the device. He could also change the internal job counter—which can reduce, or increase, a company’s bill if the device is leased, he said.

The printer break-in also enables a number of practical jokes, such as sending print and scan jobs to arbitrary workers’ desktops, O’Connor said. Also, devices could be programmed to include, for example, an image of a paper clip on every print, fax or copy, ultimately driving office staffers to take the machine apart looking for the paper clip.

Getting copies of all printed documents is definitely a security vulnerability, but I think the biggest threat is that the printers are inside the network, and are a more-trusted launching pad for onward attacks.

One of the weaknesses in the Xerox system is an unsecured boot loader, the technology that loads the basic software on the device, O’Connor said. Other flaws lie in the device’s Web interface and in the availability of services such as the Simple Network Management Protocol and Telnet, he said.

O’Connor informed Xerox of the problems in January. The company did issue a fix for its WorkCentre 200 series, it said in a statement. “Thanks to Brendan’s efforts, we were able to post a patch for our customers in mid-January which fixes the issues,” a Xerox representative said in an e-mailed statement.

One of the reasons this is a particularly nasty problem is that people don’t update their printer software. Want to bet approximately 0% of the printer’s users installed that patch? And what about printers whose code can’t be patched?

EDITED TO ADD (8/7): O’Connor’s name corrected.

Posted on August 7, 2006 at 10:59 AMView Comments

Updating the Traditional Security Model

On the Firewall Wizards mailing list last year, Dave Piscitello made a fascinating observation. Commenting on the traditional four-step security model:

Authentication (who are you)
Authorization (what are you allowed to do)
Availability (is the data accessible)
Authenticity (is the data intact)

Piscitello said:

This model is no longer sufficient because it does not include asserting the trustworthiness of the endpoint device from which a (remote) user will authenticate and subsequently access data. Network admission and endpoint control are needed to determine that the device is free of malware (esp. key loggers) before you even accept a keystroke from a user. So let’s prepend “admissibility” to your list, and come up with a 5-legged stool, or call it the Pentagon of Trust.

He’s 100% right.

Posted on August 1, 2006 at 2:03 PMView Comments

Remote-Control Airplane Software

Does anyone other than me see a problem with this?

Some 30 European businesses and research institutes are working to create software that would make it possible from a distance to regain control of an aircraft from hijackers, according to the German news magazine.

The system “which could only be controlled from the ground would conduct the aircraft posing a problem to the nearest airport whether it liked it or not,” according to extracts from next Monday’s Der Spiegel released Saturday.

“A hijacker would have no chance of reaching his goal,” it said.

Unless his goal were, um, hijacking the aircraft.

It seems to me that by designing remote-control software for airplanes, you open the possibility for someone to hijack the plane without even being on board. Sure, there are going to be computer-security controls protecting this thing, but we all know how well that sort of thing has worked in the past.

The system would be designed in such a way that even a computer hacker on board could not get round it.

But what about computer hackers on the ground?

I’m not saying this is a bad idea; it might be a good idea. But this security countermeasure opens up an entirely new vulnerability, and I hope that someone is studying that new vulnerability.

Posted on July 28, 2006 at 2:09 PMView Comments

Hacked MySpace Server Infects a Million Computers with Malware

According to The Washington Post:

An online banner advertisement that ran on MySpace.com and other sites over the past week used a Windows security flaw to infect more than a million users with spyware when people merely browsed the sites with unpatched versions of Windows….

Clever attack.

EDITED TO ADD (7/27): It wasn’t MySpace that was hacked, but a server belonging to the third-party advertising service that MySpace uses. The ad probably appeared on other websites as well, but MySpace seems to have been the biggest one.

EDITED TO ADD (8/5): Ed Felten comments.

Posted on July 24, 2006 at 6:46 AMView Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.