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When spammers try to go legitimate

September 1, 2009 by

I hate to sound like a broken record, complaining about professional mail distribution / spam-houses that are entirely unwilling to require their customers to follow a strict opt-in discipline. But I’m going to complain again and I’m going to name names.

Today, I got a spam touting a Citrix product (“Free virtualization training for you and your students!”). This message arrived in my mailbox with an unsubscribe link hosted by xmr3.com which bounced me back to a page at Citrix. The Citrix page then asks me for assorted personal information (name, email, country, employer). There was also a mailto link from xmr3 allowing me to opt-out.

At no time did I ever opt into any communication from Citrix. I’ve never done business with them. I don’t know anybody who works there. I could care less about their product.

What’s wrong here? A seemingly legitimate company is sending out spam to people who have never requested anything from them. They’re not employing any of the tactics that are normally employed by spammers to hide themselves. They’re not advertising drugs for sexual dysfunction or replicas of expensive watches. Maybe they got my email by surfing through faculty web pages. Maybe they got my email from some conference registration list. They’ve used a dubious third-party to distribute the spam who provides no method for indicating that their client is violating their terms of service (nor can their terms of service be found anywhere on their home page).

Based on this, it’s easy to advocate technical countermeasures (e.g., black-hole treatment for xmr3.com and citrix.com) or improvements to laws (the message appears to be superficially compliant with the CAN-SPAM act, but a detailed analysis would take more time than it’s worth). My hope is that we can maybe also apply some measure of shame. Citrix, as a company, should be embarrassed and ashamed to advertise itself this way. If it ever became culturally acceptable for companies to do this sort of thing, then the deluge of “legitimate” spam will be intolerable.

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Twittering for the Marines

August 6, 2009 by

The Marines recently issued an order banning social network sites (Facebook, MySpace, Twitter, etc.). The Pentagon is reviewing this sort of thing across all services. This follows on the heels of a restrictive NFL policy along the same lines. Slashdot has a nice thread, where among other things, we learn that some military personnel will contract with off-base ISPs for private Internet connections.

There are really two separate security issues to be discussed here. First, there’s the issue that military personnel might inadvertently leak information that could be used by their adversaries. This is what the NFL is worried about. The Marines order makes no mention of such leaks, and they would already be covered by rules and regulations, never mind continuing education (see, e.g., loose lips sink ships). Instead, our discussion will focus on the issue explicitly raised in the order: social networks as a vector for attackers to get at our military personnel.

For starters, there are other tools and techniques that can be used to protect people from visiting malicious web sites. There are black-list services, such as Google’s Safe Browsing, built into any recent version of Firefox. There are also better browser architectures, like Google’s Chrome, that isolate one part of the browser from another. The military could easily require the use of a specific web browser. The military could go one step further and provide sacrificial virtual machines, perhaps running on remote hosts and shared by something like VNC, to allow personnel to surf the public Internet. A solution like this seems infinitely preferable to forcing personnel to use third-party ISPs on personal computers, where vulnerable machines may well be compromised, yet go unnoticed by military sysadms. (Or worse, the ISP could itself be compromised, giving a huge amount of intel to the enemy; contrast this with the military, with its own networks and its own crypto, which presumably is designed to leak far less intel to a local eavesdropper.)

Even better, the virtual machine / remote display technique allows the military sysadm to keep all kinds of forensic data. Users’ external network behavior creates a fantastic honeynet for capturing malicious payloads. If your personnel are being attacked, you want to have the evidence in hand to sort out who the attacker is and why you’re being attacked. That helps you block future attacks and formulate any counter-measures you might take. You could do this just as well for email programs as web browsing. Might not work so well for games, but otherwise it’s a pretty powerful technique. (And, oh by the way, we’re talking about the military here, so personnel privacy isn’t as big a concern as it might be in other settings.)

It’s also important to consider the benefits of social networking. Military personnel are not machines. They’re people with spouses, children, and friends back home. Facebook is a remarkably efficient way to keep in touch with large numbers of friends without investing large amounts of time — ideal for the Marine, back from patrol, to get a nice chuckle when winding down before heading off to sleep.

In short, it’s problematic to ban social networking on “official” machines, which only pushes personnel to use these things on “unofficial” machines with “unofficial” ISPs, where you’re less likely to detect attacks and it’s harder to respond to them. Bring them in-house, in a controlled way, where you can better manage security issues and have happier personnel.

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Assorted targeted spam

July 1, 2009 by

You can run, but you can’t hide. Here are a few of the latest things I’ve seen, in no particular order.

  • On a PHPBB-style chat board which I sometimes frequent, there was a thread about do-it-yourself television repair, dormant for over a year. Recently, there was a seemingly robotic post, from a brand new user, that was still on-topic, giving general diagnosis advice and offering to sell parts for TV repair. The spam was actually somewhat germane to the main thread of the discussion. Is it still spam?
  • In my email, I recently got a press release for a local fried chicken franchise celebrating their 40th anniversary. My blogging output generally doesn’t extend to writing restaurant reviews (tempting as that might be), although I do sometimes link to foodie things from Google Reader which will also show up in my public FriendFeed. Spam or not spam?
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On China's new, mandatory censorship software

June 10, 2009 by

The New York Times reports that China will start requiring censorship software on PCs. One interesting quote stands out:

Zhang Chenming, general manager of Jinhui Computer System Engineering, a company that helped create Green Dam, said worries that the software could be used to censor a broad range of content or monitor Internet use were overblown. He insisted that the software, which neutralizes programs designed to override China’s so-called Great Firewall, could simply be deleted or temporarily turned off by the user. “A parent can still use this computer to go to porn,” he said.

In this post, I’d like to consider the different capabilities that software like this could give to the Chinese authorities, without getting too much into their motives.

Firstly, and most obviously, this software allows the authorities to do filtering of web sites and network services that originate inside or outside of the Great Firewall. By operating directly on a client machine, this filter can be aware of the operations of Tor, VPNs, and other firewall-evading software, allowing connections to a given target machine to be blocked, regardless of how the client tries to get there. (You can’t accomplish “surgical” Tor and VPN filtering if you’re only operating inside the network. You need to be on the end host to see where the connection is ultimately going.)

Software like this can do far more, since it can presumably be updated remotely to support any feature desired by the government authorities. This could be the ultimate “Big Brother Inside” feature. Not only can the authorities observe behavior or scan files within one given computer, but every computer now because a launching point for investigating other machines reachable over a local area network. If one such machine were connected, for example, to a private home network, behind a security firewall, the government software could still scan every other computer on the same private network, log every packet, and so forth. Would you be willing to give your friends the password to log into your private wireless network, knowing their machine might be running this software?

Perhaps less ominously, software like this could also be used to force users to install security patches, to uninstall zombie/botnet systems, and perform other sorts of remote systems administration. I can’t imagine the difficulty in trying to run the Central Government Bureau of National Systems Administration (would they have a phone number you could call to complain when your computer isn’t working, and could they fix it remotely?), but the technological base is now there.

Of course, anybody who owns their own computer will be able to circumvent this software. If you control your machine, you can control what’s running on it. Maybe you can pretend to be running the software, maybe not. That would turn into a technological arms race which the authorities would ultimately fail to win, though they might succeed in creating enough fear, uncertainty, and doubt to deter would-be circumventors.

This software will also have a notable impact in Internet cafes, schools, and other sorts of “public” computing resources, which are exactly the sorts of places that people might go when they want to hide their identity, and where the authorities could have physical audits to check for compliance.

Big Brother is watching.

Filed Under: Censorship & Filtering, Privacy & Security Tagged With: ,

Photo censorship vs. digital photography

June 3, 2009 by

On the 20th anniversary of the Tiananmen Square events (protests? uprising? insurrection? massacre?), the New York Times’ Lens Blog put up a great piece about the four different photographers who photographed the iconic “Tank Man”. Inevitably, half of the story concerns the technical details of being in the right place and having the right equipment configuration to capture the image (no small thing in the middle of a civil insurrection). The other half of the story, though, is about how the film got out of the camera and out to us. The story of Tank Man (NYT article, PBS Frontline piece) is quite amazing, by itself, but I want to focus on the photographers.

Tank Man, photo by Jeff Widener / AP

The most widely seen photo, by Jeff Widener, and all the other good coverage of Tank Man was all taken from one particular hotel, and the government security services were well aware of it. Our photographers had to get their images out. But how? Widener had a “long-haired college kid” assistant who smuggled several rolls of film in his underwear. Another photographer, Charlie Cole, wrote this:

After taking the picture of the showdown, I became concerned about the PSB’s surveillance of our activities on the balcony. I was down to three rolls of film, with two cameras. One roll held the tank encounter, while the other had other good pictures of crowd and PLA confrontations and of wounded civilians at a hospital.

I replaced the final unexposed roll into the one of the cameras, replacing the tank roll, and reluctantly left the other roll of the wounded in the other camera. I felt that if the PSB searched the room or caught me, they would look even harder if there was no film in the cameras.

I then placed the tank roll in a plastic film can and wrapped it in a plastic bag and attached it to the flush chain in the tank of the toilet. I hid my cameras as best I could in the room. Within an hour, the PSB forced their way in and started searching the room. After about five minutes, they discovered the cameras and ripped the film out of each, seemingly satisfied that they had neutralized the coverage. They then forced me to sign a confession that I had been photographing during martial law and confiscated my passport.

In both of these cases, the film was ultimately smuggled to the local bureau of the Associated Press who then processed, scanned, and transmitted the images. This leads me to wonder how this sort of thing would play out today, when photographers have digital cameras, where the bits are much easier to copy and transmit.

First, a few numbers. A “raw” image file from a modern Nikon D700 takes about 13MB and that already includes the (lossless) compression. Back in the film days, the biggest 35mm rolls could hold 36 images (maybe 38 if you were willing to push it on the edges), which tended to keep photographers’ desire to press the button in check. Today, when giant memory cards cost virtually nothing, it’s trivial for a photojournalist to generate tens of gigabytes of raw data in a day of work. So… how long does it take to transmit that much data? Let’s say a hotel’s Internet connection gives you a snappy 1.5 megabits of upstream bandwidth. That means it takes about 70 seconds to transmit one raw image.

If you fear the police will knock down your door at any moment, you don’t have time to send everything. That means that you, the photographer, have got to crunch your pictures through your laptop in a big hurry. If you’ve got the fastest cards and card reader, you’ll be able to copy the data to your hard drive at maybe three pictures per second. Got a thousand pictures on that memory card and you’re waiting a nerve-wracking six minutes to complete the copy.

At the point where you’re worried about somebody busting down the door, you’re not in the frame of mind to tweak with your exposure, color balance, and so forth. Pretty much all you’re thinking is “which one is the winner”, so you’re blasting through trying to select your favorites and then try to upload them.

Meanwhile, we need to consider the capabilities of the adversary. The PRC could well have prevented us from seeing Widener and Cole’s photos, simply by locking down the AP’s offices. (Two other photographers smuggled their raw film out of the country for external processing.) In the modern era, in a country like the PRC, they could just as well cut off the Internet altogether. (We already know that the PRC is cranking up the filtering of the Great Firewall to block Flickr, Twitter, and other services around the anniversary of the Tiananmen Square events, so it’s easy to imagine far more draconian policies.) This places our hypothetical digital photographer in much the same problematic space as the film photographers of twenty years ago. Now we need to smuggle the bits out by hand.

Traveling with film is a huge pain. Higher-speed film, and particularly black & white film, is annoyingly sensitive to airport x-ray scanners. It’s similarly sensitive to humidity and temperature. And, most important, you can’t see it or copy it until you process it, which isn’t really an option in a war zone. Instead, you’ve got the one roll with the one photo that you really want to get out. Alfred Hitchcock would call the film a MacGuffin and would spin a glorious tale around it.

Digital changes all that. Now, even if the Internet is down, the ability to copy bits is incredibly helpful to our photographer. An iPod, iPhone, or other such device will commonly have gigabytes of solid state storage within. That’s not enough room for everything, but it’s certainly enough room for the photographer to make copies of all the good stuff. Similarly, with memory cards getting so remarkably small (e.g., a Micro-SD card is 15mm x 11mm x 1mm), it’s easy to imagine smuggling them in a variety of places. Advantage to the photographer? Certainly so, but also very dependent on how much time and preparation was available before the police busted down the door. The CompactFlash cards used by most D-SLRs (43mm x 36mm x 3.3mm) are much harder to hide (e.g., you can’t just shove one into a crack in the floor).

There probably isn’t much point in trying to encrypt or hide the data. If the police are busting down your door, they’ll just take everything they can find and wipe everything before they give it back to you.

Filed Under: Censorship & Filtering Tagged With: