Entries Tagged "ISPs"

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An Expectation of Online Privacy

If your data is online, it is not private. Oh, maybe it seems private. Certainly, only you have access to your e-mail. Well, you and your ISP. And the sender’s ISP. And any backbone provider who happens to route that mail from the sender to you. And, if you read your personal mail from work, your company. And, if they have taps at the correct points, the NSA and any other sufficiently well-funded government intelligence organization — domestic and international.

You could encrypt your mail, of course, but few of us do that. Most of us now use webmail. The general problem is that, for the most part, your online data is not under your control. Cloud computing and software as a service exacerbate this problem even more.

Your webmail is less under your control than it would be if you downloaded your mail to your computer. If you use Salesforce.com, you’re relying on that company to keep your data private. If you use Google Docs, you’re relying on Google. This is why the Electronic Privacy Information Center recently filed a complaint with the Federal Trade Commission: many of us are relying on Google’s security, but we don’t know what it is.

This is new. Twenty years ago, if someone wanted to look through your correspondence, he had to break into your house. Now, he can just break into your ISP. Ten years ago, your voicemail was on an answering machine in your office; now it’s on a computer owned by a telephone company. Your financial accounts are on remote websites protected only by passwords; your credit history is collected, stored, and sold by companies you don’t even know exist.

And more data is being generated. Lists of books you buy, as well as the books you look at, are stored in the computers of online booksellers. Your affinity card tells your supermarket what foods you like. What were cash transactions are now credit card transactions. What used to be an anonymous coin tossed into a toll booth is now an EZ Pass record of which highway you were on, and when. What used to be a face-to-face chat is now an e-mail, IM, or SMS conversation — or maybe a conversation inside Facebook.

Remember when Facebook recently changed its terms of service to take further control over your data? They can do that whenever they want, you know.

We have no choice but to trust these companies with our security and privacy, even though they have little incentive to protect them. Neither ChoicePoint, Lexis Nexis, Bank of America, nor T-Mobile bears the costs of privacy violations or any resultant identity theft.

This loss of control over our data has other effects, too. Our protections against police abuse have been severely watered down. The courts have ruled that the police can search your data without a warrant, as long as others hold that data. If the police want to read the e-mail on your computer, they need a warrant; but they don’t need one to read it from the backup tapes at your ISP.

This isn’t a technological problem; it’s a legal problem. The courts need to recognize that in the information age, virtual privacy and physical privacy don’t have the same boundaries. We should be able to control our own data, regardless of where it is stored. We should be able to make decisions about the security and privacy of that data, and have legal recourse should companies fail to honor those decisions. And just as the Supreme Court eventually ruled that tapping a telephone was a Fourth Amendment search, requiring a warrant — even though it occurred at the phone company switching office and not in the target’s home or office — the Supreme Court must recognize that reading personal e-mail at an ISP is no different.

This essay was originally published on the SearchSecurity.com website, as the second half of a point/counterpoint with Marcus Ranum.

Posted on May 5, 2009 at 6:06 AMView Comments

"New Attack" Against Encrypted Images

In a blatant attempt to get some PR:

In a new paper, Bernd Roellgen of Munich-based encryption outfit PMC Ciphers, explains how it is possible to compare an encrypted backup image file made with almost any commercial encryption program or algorithm to an original that has subsequently changed so that small but telling quantities of data ‘leaks’.

Here’s the paper. Turns out that if you use a block cipher in Electronic Codebook Mode, identical plaintexts encrypt to identical ciphertexts.

Yeah, we already knew that.

And -1 point for a security company requiring the use of Javascript, and not failing gracefully for a browser that doesn’t have it enabled.

And — ahem — what is it with that photograph in the paper? Couldn’t the researchers have found something a little less adolescent?

For the record, I doghoused PMC Ciphers back in 2003:

PMC Ciphers. The theory description is so filled with pseudo-cryptography that it’s funny to read. Hypotheses are presented as conclusions. Current research is misstated or ignored. The first link is a technical paper with four references, three of them written before 1975. Who needs thirty years of cryptographic research when you have polymorphic cipher theory?

EDITED TO ADD (10/9): I didn’t realize it, but last year PMC Ciphers responded to my doghousing them. Funny stuff.

EDITED TO ADD (10/10): Three new commenters using dialups at the same German ISP have showed up here to defend the paper. What are the odds?

Posted on October 9, 2008 at 6:44 AMView Comments

Hacking ISP Error Pages

This is a big deal:

At issue is a growing trend in which ISPs subvert the Domain Name System, or DNS, which translates website names into numeric addresses.

When users visit a website like Wired.com, the DNS system maps the domain name into an IP address such as But if a particular site does not exist, the DNS server tells the browser that there’s no such listing and a simple error message should be displayed.

But starting in August 2006, Earthlink instead intercepts that Non-Existent Domain (NXDOMAIN) response and sends the IP address of ad-partner Barefruit’s server as the answer. When the browser visits that page, the user sees a list of suggestions for what site the user might have actually wanted, along with a search box and Yahoo ads.

The rub comes when a user is asking for a nonexistent subdomain of a real website, such as http://webmale.google.com, where the subdomain webmale doesn’t exist (unlike, say, mail in mail.google.com). In this case, the Earthlink/Barefruit ads appear in the browser, while the title bar suggests that it’s the official Google site.

As a result, all those subdomains are only as secure as Barefruit’s servers, which turned out to be not very secure at all. Barefruit neglected basic web programming techniques, making its servers vulnerable to a malicious JavaScript attack. That meant hackers could have crafted special links to unused subdomains of legitimate websites that, when visited, would serve any content the attacker wanted.

The hacker could, for example, send spam e-mails to Earthlink subscribers with a link to a webpage on money.paypal.com. Visiting that link would take the victim to the hacker’s site, and it would look as though they were on a real PayPal page.

Kaminsky demonstrated the vulnerability by finding a way to insert a YouTube video from 80s pop star Rick Astley into Facebook and PayPal domains. But a black hat hacker could instead embed a password-stealing Trojan. The attack might also allow hackers to pretend to be a logged-in user, or to send e-mails and add friends to a Facebook account.

Earthlink isn’t alone in substituting ad pages for error messages, according to Kaminsky, who has seen similar behavior from other major ISPs including Verizon, Time Warner, Comcast and Qwest.

Another article.

Posted on April 24, 2008 at 6:43 AMView Comments

My Open Wireless Network

Whenever I talk or write about my own security setup, the one thing that surprises people — and attracts the most criticism — is the fact that I run an open wireless network at home. There’s no password. There’s no encryption. Anyone with wireless capability who can see my network can use it to access the internet.

To me, it’s basic politeness. Providing internet access to guests is kind of like providing heat and electricity, or a hot cup of tea. But to some observers, it’s both wrong and dangerous.

I’m told that uninvited strangers may sit in their cars in front of my house, and use my network to send spam, eavesdrop on my passwords, and upload and download everything from pirated movies to child pornography. As a result, I risk all sorts of bad things happening to me, from seeing my IP address blacklisted to having the police crash through my door.

While this is technically true, I don’t think it’s much of a risk. I can count five open wireless networks in coffee shops within a mile of my house, and any potential spammer is far more likely to sit in a warm room with a cup of coffee and a scone than in a cold car outside my house. And yes, if someone did commit a crime using my network the police might visit, but what better defense is there than the fact that I have an open wireless network? If I enabled wireless security on my network and someone hacked it, I would have a far harder time proving my innocence.

This is not to say that the new wireless security protocol, WPA, isn’t very good. It is. But there are going to be security flaws in it; there always are.

I spoke to several lawyers about this, and in their lawyerly way they outlined several other risks with leaving your network open.

While none thought you could be successfully prosecuted just because someone else used your network to commit a crime, any investigation could be time-consuming and expensive. You might have your computer equipment seized, and if you have any contraband of your own on your machine, it could be a delicate situation. Also, prosecutors aren’t always the most technically savvy bunch, and you might end up being charged despite your innocence. The lawyers I spoke with say most defense attorneys will advise you to reach a plea agreement rather than risk going to trial on child-pornography charges.

In a less far-fetched scenario, the Recording Industry Association of America is known to sue copyright infringers based on nothing more than an IP address. The accuser’s chance of winning is higher than in a criminal case, because in civil litigation the burden of proof is lower. And again, lawyers argue that even if you win it’s not worth the risk or expense, and that you should settle and pay a few thousand dollars.

I remain unconvinced of this threat, though. The RIAA has conducted about 26,000 lawsuits, and there are more than 15 million music downloaders. Mark Mulligan of Jupiter Research said it best: “If you’re a file sharer, you know that the likelihood of you being caught is very similar to that of being hit by an asteroid.”

I’m also unmoved by those who say I’m putting my own data at risk, because hackers might park in front of my house, log on to my open network and eavesdrop on my internet traffic or break into my computers. This is true, but my computers are much more at risk when I use them on wireless networks in airports, coffee shops and other public places. If I configure my computer to be secure regardless of the network it’s on, then it simply doesn’t matter. And if my computer isn’t secure on a public network, securing my own network isn’t going to reduce my risk very much.

Yes, computer security is hard. But if your computers leave your house, you have to solve it anyway. And any solution will apply to your desktop machines as well.

Finally, critics say someone might steal bandwidth from me. Despite isolated court rulings that this is illegal, my feeling is that they’re welcome to it. I really don’t mind if neighbors use my wireless network when they need it, and I’ve heard several stories of people who have been rescued from connectivity emergencies by open wireless networks in the neighborhood.

Similarly, I appreciate an open network when I am otherwise without bandwidth. If someone were using my network to the point that it affected my own traffic or if some neighbor kid was dinking around, I might want to do something about it; but as long as we’re all polite, why should this concern me? Pay it forward, I say.

Certainly this does concern ISPs. Running an open wireless network will often violate your terms of service. But despite the occasional cease-and-desist letter and providers getting pissy at people who exceed some secret bandwidth limit, this isn’t a big risk either. The worst that will happen to you is that you’ll have to find a new ISP.

A company called Fon has an interesting approach to this problem. Fon wireless access points have two wireless networks: a secure one for you, and an open one for everyone else. You can configure your open network in either “Bill” or “Linus” mode: In the former, people pay you to use your network, and you have to pay to use any other Fon wireless network. In Linus mode, anyone can use your network, and you can use any other Fon wireless network for free. It’s a really clever idea.

Security is always a trade-off. I know people who rarely lock their front door, who drive in the rain (and, while using a cell phone) and who talk to strangers. In my opinion, securing my wireless network isn’t worth it. And I appreciate everyone else who keeps an open wireless network, including all the coffee shops, bars and libraries I have visited in the past, the Dayton International Airport where I started writing this and the Four Points Sheraton where I finished. You all make the world a better place.

This essay originally appeared on Wired.com, and has since generated a lot of controversy. There’s a Slashdot thread. And here are three opposing essays and three supporting essays. Presumably there will be a lot of back and forth in the comments section here as well.

EDITED TO ADD (1/15): There has been lots more commentary.

EDITED TO ADD (1/16): Even more commentary. And still more.

EDITED TO ADD (1/17): Two more.

EDITED TO ADD (1/18): Another. In the beginning, comments agreeing with me and disagreeing with me were about tied. By now, those that disagree with me are firmly in the lead.

Posted on January 15, 2008 at 3:33 AMView Comments

Security by Letterhead

This otherwise amusing story has some serious lessons:

John: Yes, I’m calling to find out why request number 48931258 to transfer somedomain.com was rejected.

ISP: Oh, it was rejected because the request wasn’t submitted on company letterhead.

John: Oh… sure… but… uh, just so we’re on the same page, can you define exactly what you mean by ‘company letterhead?’

ISP: Well, you know, it has the company’s logo, maybe a phone number and web site address… that sort of thing. I mean, your fax looks like it could’ve been typed by anyone!

John: So you know what my company letterhead looks like?

ISP: Ye… no. Not specifically. But, like, we’d know it if we saw it.

John: And what if we don’t have letterhead? What if we’re a startup? What if we’re redesigning our logo?

ISP: Well, you’d have to speak to customer–

John (clicking and typing): I could probably just pick out a semi-professional-looking MS Word template and paste my request in that and resubmit it, right?

ISP: Look, our policy–

John: Oh, it’s ok, I just sent the request back in on letterhead.

Ha ha. The idiot ISP guy doesn’t realize how easy it for anyone with a word processor and a laser printer to fake a letterhead. But what this story really shows is how hard it is for people to change their security intuition. Security-by-letterhead was fairly robust when printing was hard, and faking a letterhead was real work. Today it’s easy, but people — especially people who grew up under the older paradigm — don’t act as if it is. They would if they thought about it, but most of the time our security runs on intuition and not on explicit thought.

This kind of thing bites us all the time. Mother’s maiden name is no longer a good password. An impressive-looking storefront on the Internet is not the same as an impressive-looking storefront in the real world. The headers on an e-mail are not a good authenticator of its origin. It’s an effect of technology moving faster than our ability to develop a good intuition about that technology.

And, as technology changes ever increasingly faster, this will only get worse.

Posted on October 30, 2007 at 6:33 AMView Comments

Federal Judge Strikes Down National-Security-Letter Provision of Patriot Act

Article, ACLU press release, some legal commentary, and actual decision.

From the article:

The ACLU had challenged the law on behalf of an Internet service provider, complaining that the law allowed the FBI to demand records without the kind of court supervision required for other government searches. Under the law, investigators can issue so-called national security letters to entities like Internet service providers and phone companies and demand customers’ phone and Internet records.

In his ruling, Marrero said much more was at stake than questions about the national security letters.

He said Congress, in the original USA Patriot Act and less so in a 2005 revision, had essentially tried to legislate how the judiciary must review challenges to the law. If done to other bills, they ultimately could all “be styled to make the validation of the law foolproof.”

Noting that the courthouse where he resides is several blocks from the fallen World Trade Center, the judge said the Constitution was designed so that the dangers of any given moment could never justify discarding fundamental individual liberties.

He said when “the judiciary lowers its guard on the Constitution, it opens the door to far-reaching invasions of liberty.”

Regarding the national security letters, he said, Congress crossed its boundaries so dramatically that to let the law stand might turn an innocent legislative step into “the legislative equivalent of breaking and entering, with an ominous free pass to the hijacking of constitutional values.”

He said the ruling does not mean the FBI must obtain the approval of a court prior to ordering records be turned over, but rather must justify to a court the need for secrecy if the orders will last longer than a reasonable and brief period of time.

Note that judge immediately stayed his decision, pending appeal.

EDITED TO ADD (9/9): More legal commentary.

Posted on September 7, 2007 at 10:05 AMView Comments

Swiss Police to Use Trojans for VoIP Tapping

At least they’re thinking about it:

Swiss authorities are investigating the possibility of tapping VoIP calls, which could involve commandeering ISPs to install Trojan code on target computers.

VoIP calls through software services such as Skype are encrypted as they are passed over the public Internet, in order to safeguard the privacy of the callers.

This presents a problem for anyone wanting to listen in, as they are faced with trying to decrypt the packets by brute force — not easy during a three-minute phone call. What’s more, many VoIP services are not based in Switzerland, so the authorities don’t have the jurisdiction to force them to hand over the decryption keys or offer access to calls made through these services.

The only alternative is to find a means of listening in at a point before the data is encrypted.


In order to install the application on the target computer, the Swiss authorities
envisage two strategies: either have law enforcement surreptitiously install it locally, or have the telco or ISP which provides Internet access to that computer install it remotely.

The application, essentially a piece of Trojan code, is also able to turn on the microphone on the target PC and monitor not just VoIP conversations, but also any other ambient audio.

Posted on October 18, 2006 at 2:26 PMView Comments

Your ISP May Be Spying on You

From News.com:

The U.S. Department of Justice is quietly shopping around the explosive idea of requiring Internet service providers to retain records of their customers’ online activities.

Data retention rules could permit police to obtain records of e-mail chatter, Web browsing or chat-room activity months after Internet providers ordinarily would have deleted the logs–that is, if logs were ever kept in the first place. No U.S. law currently mandates that such logs be kept.

I think the big idea here is that the Internet makes a massive surveillance society so easy. And data storage will only get cheaper.

Posted on June 28, 2005 at 8:16 AMView Comments

T-Mobile Hack

For at least seven months last year, a hacker had access to T-Mobile’s customer network. He’s known to have accessed information belonging to 400 customers — names, Social Security numbers, voicemail messages, SMS messages, photos — and probably had the ability to access data belonging to any of T-Mobile’s 16.3 million U.S. customers. But in its fervor to report on the security of cell phones, and T-Mobile in particular, the media missed the most important point of the story: The security of much of our data is not under our control.

This is new. A dozen years ago, if someone wanted to look through your mail, they would have to break into your house. Now they can just break into your ISP. Ten years ago, your voicemail was on an answering machine in your house; now it’s on a computer owned by a telephone company. Your financial data is on Websites protected only by passwords. The list of books you browse, and the books you buy, is stored in the computers of some online bookseller. Your affinity card allows your supermarket to know what food you like. Data that used to be under your direct control is now controlled by others.

We have no choice but to trust these companies with our privacy, even though the companies have little incentive to protect that privacy. T-Mobile suffered some bad press for its lousy security, nothing more. It’ll spend some money improving its security, but it’ll be security designed to protect its reputation from bad PR, not security designed to protect the privacy of its customers.

This loss of control over our data has other effects, too. Our protections against police abuse have been severely watered down. The courts have ruled that the police can search your data without a warrant, as long as that data is held by others. The police need a warrant to read the e-mail on your computer; but they don’t need one to read it off the backup tapes at your ISP. According to the Supreme Court, that’s not a search as defined by the 4th Amendment.

This isn’t a technology problem, it’s a legal problem. The courts need to recognize that in the information age, virtual privacy and physical privacy don’t have the same boundaries. We should be able to control our own data, regardless of where it is stored. We should be able to make decisions about the security and privacy of that data, and have legal recourse should companies fail to honor those decisions. And just as the Supreme Court eventually ruled that tapping a telephone was a Fourth Amendment search, requiring a warrant — even though it occurred at the phone company switching office — the Supreme Court must recognize that reading e-mail at an ISP is no different.

This essay appeared in eWeek.

Posted on February 14, 2005 at 4:26 PMView Comments

Sidebar photo of Bruce Schneier by Joe MacInnis.