Linux-Fu: Your Own Dynamic DNS

3d anime monster pornoIt is a problem as old as the Internet. You want to access your computer remotely, but it is behind a router that randomly gets different IP addresses. Or maybe it is your laptop and it winds up in different locations with, again, different IP addresses. There are many ways to solve this problem and some of them are better than others.

3d anime monster pornoA lot of routers can report their IP address to a dynamic DNS server. That used to be great, but now it seems like many of them hound you to upgrade or constantly renew so you can see their ads. Some of them disappear, too. If your router vendor supplies one, that might be a good choice, until you change routers, of course. OpenWRT supports many such services and there are many lists of common services.

However, if you have a single public accessible computer, for example a Web server or even a cloud instance, and you are running your own DNS server, you really don’t need one of those services. I’m going to show you how I do it with an accessible Linux server running Bind. This is a common setup, but if you have a different system you might have to adapt a bit.

There are many ways to set up dynamic DNS if you are willing to have a great deal of structure on both sides. Most of these depend on setting up a secret key to allow for DNS updates and some sort of script that calls nsupdate or having the DHCP server do it. The problem is, I have a lot of client computers and many are set up differently. I wanted a system where the only thing needed on the client side was ssh. All the infrastructure remains on the DNS server.

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An Old Calculator Lives Again

There was a time when any electronics student would have a slide rule hanging off their belt. By the 1970s, the slide rule changed over to an electronic calculator which was a pricy item. Today you can buy calculators at the dollar store. [JohnAudioTech] pulled out an old Radio Shack vacuum fluorescent display (VFD) calculator and found it didn’t work. Obviously, that means it is time to open it up.

It is fun to see one of these old devices opened up again. Consumer electronics with big through-hole ICs! Troubleshooting the device wound up being anti-climatic, as a broken wire to the battery compartment explained the whole thing.

As a teardown, though, this is a fun video. Not only are all the parts through-hole, but the PCB is clearly a manual layout with serpentine traces flowing across the board like some sort of art piece. Continue reading “An Old Calculator Lives Again”

Hacking D-Link Firmware

When [0xRickSanchez] found some D-Link firmware he couldn’t unpack, he was curious to find out why. The firmware had a new encryption method which was doing its job of preventing tampering and static analysis. Of course, he had to figure out how to get around it and is documenting his work in a series of blog posts.

Looking at the entropy analysis showed the data to be totally random,? a good sign it was either encrypted or compressed. The target router cost about $200, but a similar cheaper router used the same encryption and thus this model became the hardware of choice for testing.

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Raspberry Pi Makes A Practical Tricorder

What do you get when you add a thermal camera, a software-defined radio dongle, and a battery to a Raspberry Pi? If you are [saveitforparts] you make a tricorder for sniffing radio signals and viewing heat signatures. He admits, the videos (see below) aren’t exactly a “how-to” but it will still give you some ideas for your next build.

You can sense the frustration with some Linux configuration issues, but [saveitforparts] admits he isn’t a Linux or Raspberry Pi guru. Version 1 seemed to be a bit of a prototype, but version 2 is more polished. We still aren’t sure we’d see Spock carrying a case like that, but some 3D printing could spiff that right up.

Of course, a real tricorder is a McGuffin that does whatever the plot calls for. This one is a bit more practical, but it can monitor thermal and RF energy and could accommodate more sensors. This is a great example of a project that would have been very hard to do in the past but is much easier today. The availability of cheap computers and ready-made modules along with associated software open up many possibilities.

If you want to do your own Tricorder hacking you could take over a commercial model. Then again, there’s an official replica on its way that seems like it might have some similar features.

Lithium Sulfur Batteries Slated For Takeoff

Spectrum recently published a post on a new lithium sulfur battery technology specifically targeting electric aviation applications. Although lots of electric vehicles could benefit from the new technology, airplanes are especially sensitive to heavy batteries and lithium-sulfur batteries can weigh much less than modern batteries of equivalent capacity. The Spectrum post is from Oxis Energy who is about to fly tests with the new batteries which they claim have twice the energy density of conventional lithium-ion batteries. The company also claims the batteries are safer, which is another important consideration when flying through the sky.

The batteries have a cathode comprised of aluminum foil coated with carbon and sulfur — which avoids the use of cobalt, a cost driver in traditional lithium cell chemistries. The anode is pure lithium foil. Between the two electrodes is a separator soaked in an electrolyte. The company says the batteries go through multiple stages as they discharge, forming different chemical compounds that continue to produce electricity through chemical action.

The safety factor is due to the fact that, unlike lithium-ion cells, the new batteries don’t form dendrites that short out the cell. The cells do degrade over time, but not in a way that is likely to cause a short circuit. However, ceramic coatings may provide protection against this degradation in the future which would be another benefit compared to traditional lithium batteries.

We see a lot of exciting battery announcements, but we rarely see real products with them. Time will tell if the Oxis and similar batteries based on this technology will take root.

The CIA’s Corona Project Was About Satellites, Not A Virus

We take orbital imagery for granted these days, but there was a time that it was high technology and highly secretive. [Scott Manley] has a good overview of the CIA’s Corona spy satellites, along with declassified images from the early days of the program.

It seems strange today, but the spy images needed high resolution and the only practical technology at the time was film. The satellite held a whopping 3,000 feet of film and, once shot, a capsule or bucket would return to Earth for retrieval and development. They didn’t make it to land — or at least they weren’t supposed to. The CIA didn’t want opponents sweeping up the film so an airplane was supposed to snag the bucket as it descended on a parachute, a topic covered in [Tom Nardi’s] article about the history of catching stuff as it falls from space.

The early cameras could see detail down to about 40 feet. By the end of the program in the 1970s, improved cameras could see down to 3 feet or less. Later satellites had a 3D-capable camera and multiple return buckets. The satellites were — officially — a program to expose biological samples to the space environment and return them for analysis. The Discover program was pure cover and the whole thing was declassified in 1992.

Of course, film from airplanes also had a role. Some spy satellites tried to scan film and send the data back, but that saw more use on lunar missions where returning a capsule to Earth was a lot more difficult.

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FBI Reports On Linux Drovorub Malware

The FBI and the NSA released a report on the Russian-based malware that attacks Linux known as Drovorub (PDF) and it is an interesting read. Drovorub uses a kernel module rootkit and allows a remote attacker to control your computer, transfer files, and forward ports. And the kernel module takes extraordinary steps to avoid detection while doing it.

What is perhaps most interesting though, is that the agencies did the leg work to track the malware to its source: the GRU — Russian intelligence. The name Drovorub translates into “woodcutter” and is apparently the name the GRU uses for the program.

A look inside the code shows it is pretty mundane. There’s a server with a JSON configuration file and a MySQL backend. It looks like any other garden-variety piece of code. To bootstrap the client, a hardcoded configuration allows the program to make contact with the server and then creates a configuration file that the kernel module actively hides. Interestingly, part of the configuration is a UUID that contains the MAC address of the server computer.

The rootkit won’t persist if you have UEFI boot fully enabled (although many Linux computers turn UEFI signing off rather than work through the steps to install an OS with it enabled). The malware is easy to spot if you dump raw information from the network, but the kernel module makes it hard to find on the local machine. It hooks many kernel functions so it can hide processes from both the ps command and the /proc filesystem. Other hooks remove file names from directory listings and also hides sockets. The paper describes how to identify the malware and they are especially interested in detection at scale — that is, if you have 1,000 Linux PCs on a network, how do you find which ones have this infection?

This is a modern spy story, but not quite what we’ve come to expect in Bond movies. “Well, Moneypenny, it appears Spectre is using the POCO library to generate UUIDs,” is hard to work into a trailer. We prefer the old days when high-tech spying meant nonlinear junction detectors, hacking Selectrics, moon probe heists, and passive bugging.