Entries Tagged "network security"

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Benevolent Worms

Yet another story about benevolent worms and how they can secure our networks. This idea shows up every few years. (I wrote about it in 2000, and again in 2003. This quote (emphasis mine) from the article shows what the problem is:

Simulations show that the larger the network grows, the more efficient this scheme should be. For example, if a network has 50,000 nodes (computers), and just 0.4% of those are honeypots, just 5% of the network will be infected before the immune system halts the virus, assuming the fix works properly. But, a 200-million-node network ­ with the same proportion of honeypots ­ should see just 0.001% of machines get infected.

This is from my 2003 essay:

A worm is not “bad” or “good” depending on its payload. Viral propagation mechanisms are inherently bad, and giving them beneficial payloads doesn’t make things better. A worm is no tool for any rational network administrator, regardless of intent.

A good software distribution mechanism has the following characteristics:

  1. People can choose the options they want.
  2. Installation is adapted to the host it’s running on.
  3. It’s easy to stop an installation in progress, or uninstall the software.
  4. It’s easy to know what has been installed where.

A successful worm, on the other hand, runs without the consent of the user. It has a small amount of code, and once it starts to spread, it is self-propagating, and will keep going automatically until it’s halted.

These characteristics are simply incompatible. Giving the user more choice, making installation flexible and universal, allowing for uninstallation—all of these make worms harder to propagate. Designing a better software distribution mechanism, makes it a worse worm, and vice versa. On the other hand, making the worm quieter and less obvious to the user, making it smaller and easier to propagate, and making it impossible to contain, all make for bad software distribution.

All of this makes worms easy to get wrong and hard to recover from. Experimentation, most of it involuntary, proves that worms are very hard to debug successfully: in other words, once worms starts spreading it’s hard to predict exactly what they will do. Some viruses were written to propagate harmlessly, but did damage—ranging from crashed machines to clogged networks—because of bugs in their code. Many worms were written to do damage and turned out to be harmless (which is even more revealing).

Intentional experimentation by well-meaning system administrators proves that in your average office environment, the code that successfully patches one machine won’t work on another. Indeed, sometimes the results are worse than any threat of external attack. Combining a tricky problem with a distribution mechanism that’s impossible to debug and difficult to control is fraught with danger. Every system administrator who’s ever distributed software automatically on his network has had the “I just automatically, with the press of a button, destroyed the software on hundreds of machines at once!” experience. And that’s with systems you can debug and control; self-propagating systems don’t even let you shut them down when you find the problem. Patching systems is fundamentally a human problem, and beneficial worms are a technical solution that doesn’t work.

Posted on December 5, 2005 at 2:50 PMView Comments

Sniffing Passwords is Easy

From InfoWorld:

She said about half the hotels use shared network media (i.e., a hub versus an Ethernet switch), so any plain text password you transmit is sniffable by any like-minded person in the hotel. Most wireless access points are shared media as well; even networks requiring a WEP key often allow the common users to sniff each other’s passwords.

She said the average number of passwords collected in an overnight hotel stay was 118, if you throw out the 50 percent of connections that used an Ethernet switch and did not broadcast passwords.

The vast majority, 41 percent, were HTTP-based passwords, followed by e-mail (SMTP, POP2, IMAP) at 40 percent. The last 19 percent were composed of FTP, ICQ, SNMP, SIP, Telnet, and a few other types.

As a security professional, my friend often attends security conferences and teaches security classes. She noted that the number of passwords she collected in these venues was higher on average than in non-security locations. The very people who are supposed to know more about security than anyone appeared to have a higher-than-normal level of remote access back to their companies, but weren’t using any type of password protection.

At one conference, she listened to one of the world’s foremost Cisco security experts as his laptop broadcast 12 different log-in types and passwords during the presentation. Ouch!

I am interested in analyzing that password database. What percentage of those passwords are English words? What percentage are in the common password dictionaries? What percentage use mixed case, or numbers, or punctuation? What’s the frequency distribution of different password lengths?

Real password data is hard to come by. There’s an interesting research paper in that data.

Posted on November 9, 2005 at 2:39 PMView Comments

A U.S. National Firewall

This seems like a really bad idea:

Government has the right—even the responsibility—to see that its laws and regulations are enforced. The Internet is no exception. When the Internet is being used on American soil, it should comply with American law. And if it doesn’t, then the government should be able to step in and filter the illegal sites and activities.

Posted on September 7, 2005 at 3:53 PMView Comments

A Socio-Technical Approach to Internet Security

Interesting research grant from the NSF:

Technical security measures are often breached through social means, but little research has tackled the problem of system security in the context of the entire socio-technical system, with the interactions between the social and technical parts integrated into one model. Similar problems exist in the field of system safety, but recently a new accident model has been devised that uses a systems-theoretic approach to understand accident causation. Systems theory allows complex relationships between events and the system as a whole to be taken into account, so this new model permits an accident to be considered not simply as arising from a chain of individual component failures, but from the interactions among system components, including those that have not failed.

This exploratory research will examine how this new approach to safety can be applied to Internet security, using worms as a first example. The long-term goal is to create a general model of trustworthiness that can incorporate both safety and security, along with system modeling tools and analysis methods that can be used to create more trustworthy socio-technical systems. This research provides a unique opportunity to link two research disciplines, safety and security, that have many commonalities but, up to now, relatively little communication or interaction.

Posted on August 25, 2005 at 7:38 AMView Comments

The Devil's Infosec Dictionary

I want “The Devil’s Infosec Dictionary” to be funnier. And I wish the entry that mentions me—”Cryptography: The science of applying a complex set of mathematical algorithms to sensitive data with the aim of making Bruce Schneier exceedingly rich”—were more true.

In any case, I’ll bet the assembled here can come up with funnier infosec dictionary definitions. Post them as comments here, and—if there are enough good ones—I’ll collect them up on a single page.

Posted on August 13, 2005 at 10:48 AMView Comments

Wireless Interception Distance Records

Don’t believe wireless distance limitations. Again and again they’re proven wrong.

At DefCon earlier this month, a group was able to set up an unamplified 802.11 network at a distance of 124.9 miles.

The record holders relied on more than just a pair of wireless laptops. The equipment required for the feat, according to the event website, included a “collection of homemade antennas, surplus 12 foot satellite dishes, home-welded support structures, scaffolds, ropes and computers”.

Bad news for those of us who rely on physical distance to secure our wireless networks.

Even more important, the world record for communicating with a passive RFID device was set at 69 feet. (Pictures here.) Remember that the next time someone tells you that it’s impossible to read RFID identity cards at a distance.

Whenever you hear a manufacturer talk about a distance limitation for any wireless technology—wireless LANs, RFID, Bluetooth, anything—assume he’s wrong. If he’s not wrong today, he will be in a couple of years. Assume that someone who spends some money and effort building more sensitive technology can do much better, and that it will take less money and effort over the years. Technology always gets better; it never gets worse. If something is difficult and expensive now, it will get easier and cheaper in the future.

Posted on August 8, 2005 at 1:37 PMView Comments

Eavesdropping on Bluetooth Automobiles

This is impressive:

This new toool is called The Car Whisperer and allows people equipped with a Linux Laptop and a directional antenna to inject audio to, and record audio from bypassing cars that have an unconnected Bluetooth handsfree unit running. Since many manufacturers use a standard passkey which often is the only authentication that is needed to connect.

This tool allows to interact with other drivers when traveling or maybe used in order to talk to that pushy Audi driver right behind you 😉 . It also allows to eavesdrop conversations in the inside of the car by accessing the microphone.

EDITED TO ADD: Another article.

Posted on August 2, 2005 at 1:41 PMView Comments

Cisco Harasses Security Researcher

I’ve written about full disclosure, and how disclosing security vulnerabilities is our best mechanism for improving security—especially in a free-market system. (That essay is also worth reading for a general discussion of the security trade-offs.) I’ve also written about how security companies treat vulnerabilities as public-relations problems first and technical problems second. This week at BlackHat, security researcher Michael Lynn and Cisco demonstrated both points.

Lynn was going to present security flaws in Cisco’s IOS, and Cisco went to inordinate lengths to make sure that information never got into the hands of the their consumers, the press, or the public.

Cisco threatened legal action to stop the conference’s organizers from allowing a 24-year-old researcher for a rival tech firm to discuss how he says hackers could seize control of Cisco’s Internet routers, which dominate the market. Cisco also instructed workers to tear 20 pages outlining the presentation from the conference program and ordered 2,000 CDs containing the presentation destroyed.

In the end, the researcher, Michael Lynn, went ahead with a presentation, describing flaws in Cisco’s software that he said could allow hackers to take over corporate and government networks and the Internet, intercepting and misdirecting data communications. Mr. Lynn, wearing a white hat emblazoned with the word “Good,” spoke after quitting his job at Internet Security Systems Inc. Wednesday. Mr. Lynn said he resigned because ISS executives had insisted he strike key portions of his presentation.

Not being able to censor the information, Cisco decided to act as if it were no big deal:

In a release shortly after the presentation, Cisco stated, “It is important to note that the information Lynn presented was not a disclosure of a new vulnerability or a flaw with Cisco IOS software. Lynn’s research explores possible ways to expand exploitations of known security vulnerabilities impacting routers.” And went on to state “Cisco believes that the information Lynn presented at the Blackhat conference today contained proprietary information and was illegally obtained.” The statement also refers to the fact that Lynn stated in his presentation that he used a popular file decompressor to ‘unzip’ the Cisco image before reverse engineering it and finding the flaw, which is against Cisco’s use agreement.

The Cisco propaganda machine is certainly working overtime this week.

The security implications of this are enormous. If companies have the power to censor information about their products they don’t like, then we as consumers have less information with which to make intelligent buying decisions. If companies have the power to squelch vulnerability information about their products, then there’s no incentive for them to improve security. (I’ve written about this in connection to physical keys and locks.) If free speech is subordinate to corporate demands, then we are all much less safe.

Full disclosure is good for society. But because it helps the bad guys as well as the good guys (see my essay on secrecy and security for more discussion of the balance), many of us have championed “responsible disclosure” guidelines that give vendors a head start in fixing vulnerabilities before they’re announced.

The problem is that not all researchers follow these guidelines. And laws limiting free speech do more harm to society than good. (In any case, laws won’t completely fix the problem; we can’t get laws passed in every possible country security researchers live.) So the only reasonable course of action for a company is to work with researchers who alert them to vulnerabilities, but also assume that vulnerability information will sometimes be released without prior warning.

I can’t imagine the discussions inside Cisco that led them to act like thugs. I can’t figure out why they decided to attack Michael Lynn, BlackHat, and ISS rather than turn the situation into a public-relations success. I can’t believe that they thought they could have censored the information by their actions, or even that it was a good idea.

Cisco’s customers want information. They don’t expect perfection, but they want to know the extent of problems and what Cisco is doing about them. They don’t want to know that Cisco tries to stifle the truth:

Joseph Klein, senior security analyst at the aerospace electronic systems division for Honeywell Technology Solutions, said he helped arrange a meeting between government IT professionals and Lynn after the talk. Klein said he was furious that Cisco had been unwilling to disclose the buffer-overflow vulnerability in unpatched routers. “I can see a class-action lawsuit against Cisco coming out of this,” Klein said.

ISS didn’t come out of this looking very good, either:

“A few years ago it was rumored that ISS would hold back on certain things because (they’re in the business of) providing solutions,” [Ali-Reza] Anghaie, [a senior security engineer with an aerospace firm, who was in the audience,] said. “But now you’ve got full public confirmation that they’ll submit to the will of a Cisco or Microsoft, and that’s not fair to their customers…. If they’re willing to back down and leave an employee … out to hang, well what are they going to do for customers?”

Despite their thuggish behavior, this has been a public-relations disaster for Cisco. Now it doesn’t matter what they say—we won’t believe them. We know that the public-relations department handles their security vulnerabilities, and not the engineering department. We know that they think squelching information and muzzling researchers is more important than informing the public. They could have shown that they put their customers first, but instead they demonstrated that short-sighted corporate interests are more important than being a responsible corporate citizen.

And these are the people building the hardware that runs much of our infrastructure? Somehow, I don’t feel very secure right now.

EDITED TO ADD: I am impressed with Lynn’s personal integrity in this matter:

When Mr. Lynn took the stage yesterday, he was introduced as speaking on a different topic, eliciting boos. But those turned to cheers when he asked, “Who wants to hear about Cisco?” As he got started, Mr. Lynn said, “What I just did means I’m about to get sued by Cisco and ISS. Not to put too fine a point on it, but bring it on.”

And this:

Lynn closed his talk by directing the audience to his resume and asking if anyone could give him a job.

“In large part I had to quit to give this presentation because ISS and Cisco would rather the world be at risk, I guess,” Lynn said. “They had to do what’s right for their shareholders; I understand that. But I figured I needed to do what’s right for the country and for the national critical infrastructure.”

There’s a lawsuit against him. I’ll let you know if there’s a legal defense fund.

EDITED TO ADD: The lawsuit has been settled. Some details:

Michael Lynn, a former ISS researcher, and the Black Hat organisers agreed to a permanent injunction barring them from further discussing the presentation Lynn gave on Wednesday. The presentation showed how attackers could take over Cisco routers, a problem that Lynn said could bring the Internet to its knees.

The injunction also requires Lynn to return any materials and disassembled code related to Cisco, according to a copy of the injunction, which was filed in US District Court for the District of Northern California. The injunction was agreed on by attorneys for Lynn, Black Hat, ISS and Cisco.

Lynn is also forbidden to make any further presentations at the Black Hat event, which ended on Thursday, or the following Defcon event. Additionally, Lynn and Black Hat have agreed never to disseminate a video made of Lynn’s presentation and to deliver to Cisco any video recording made of Lynn.

My hope is that Cisco realized that continuing with this would be a public-relations disaster.

EDITED TO ADD: Lynn’s BlackHat presentation is on line.

EDITED TO ADD: The FBI is getting involved.

EDITED TO ADD: The link to the presentation, above, has been replaced with a cease-and-desist letter. A copy of the presentation is now here.

Posted on July 29, 2005 at 4:35 AMView Comments

Microsoft Builds In Security Bypasses

I am very suspicious of tools that allow you to bypass network security systems. Yes, they make life easier. But if security is important, than all security decisions should be made by a central process; tools that bypass that centrality are very risky.

I didn’t like SOAP for that reason, and I don’t like the sound of this new Microsoft thingy:

We’re always looking for new things that can allow you to do things uniquely different today. For example, this new feature tool we have would allow me to tunnel directly using HTTP into my corporate Exchange server without having to go through the whole VPN (virtual private network) process, bypassing the need to use a smart card. It’s such a huge time-saver, for me at least, compared to how long it takes me now. We will be extending that functionality to the next version of Windows.

That’s Martin Taylor, Microsoft’s general manager of platform strategy, talking.

Posted on July 26, 2005 at 1:20 PMView Comments

Sidebar photo of Bruce Schneier by Joe MacInnis.