Review: NEJE DK-8-KZ Laser Engraver

March 1, 2018 by Tom Nardi 100 Comments

When I got my first 3D printer I was excited, but now that I’m contemplating adding a forth to my collection, I have to come to the terms with the fact that these machines have all the novelty of a screwdriver at this point. Which is fine; getting the cost down and availability up is the key to turning a niche piece of technology into a mainstream tool, and the more people with 3D printers at home or in their workshop the better, as far as I’m concerned. But still, there’s a certain thrill in exploring the cutting edge, and I’ve been looking for something new to get excited about as of late.

Lasers seem like an interesting next step in my quest towards complete in-house fabrication capability, so I started researching cheap setups to get my feet wet. In the course of looking up diode-powered laser cutters, I came across the NEJE DK-8-KZ. At only 1W, there’s no question this device isn’t going to be cutting a whole lot. In fact, it’s specifically sold as an engraver. But given the fact that you can get one of these little guys for around $70 USD shipped, it’s hard to complain.

Now I wasn’t 100% sure what I would do with a laser engraver, but I thought it would be a good way to test the waters before putting serious money (and time) into something more powerful. Plus, if I’m being totally honest, I wanted to start on something on the lower end of the power spectrum because I’m terrified of blinding myself.

So what kind of laser do you get for $70? Let’s find out… Continue reading “Review: NEJE DK-8-KZ Laser Engraver” →

Memcached Servers Abused For DDoS Attacks

March 1, 2018 by Bob Baddeley 11 Comments

Cloudflare announced recently that they are seeing an increase in amplification attacks using memcached servers, and that this exploit has the potential to be a big problem because memcached is capable of amplifying an attack significantly. This takes DDoS attacks to a new level, but the good news is that the problem is confined to a few thousand misconfigured servers, and the solution is to put the servers behind a tighter firewall and to disable UDP. What’s interesting is how the fundamental workings of the Internet are exploited to create and direct a massive amount of traffic.

We start with a botnet. This is when a bunch of Internet-connected devices are compromised and controlled by a malicious user. This could be a set of specific brand of web camera or printer or computer with unsecured firmware. Once the device is compromised, the malicious user can control the botnet and have it execute code. This code could mine cryptocurrency, upload sensitive data, or create a lot of web traffic directed at a particular server, flooding it with requests and creating a distributed denial of service (DDoS) attack that takes down the server. Since the server can’t distinguish regular traffic from malicious traffic, it can’t filter it out and becomes unresponsive.

This DDoS attack is limited to the size of the botnet’s bandwidth, though. If all the web cameras in the botnet are pounding a server as fast as they can, the botnet has reached its max. The next trick is called an amplification attack, and it exploits UDP. UDP (as opposed to TCP) is like the early post office; you send mail and hope it gets there, and if it doesn’t then oh well. There’s no handshaking between communicating computers. When a device sends a UDP packet to a server, it includes the return address so that the server can send the response back. If the device sends a carefully crafted fake request with a different return address, then the server will send the response to that spoofed return address.

So if the web camera sends a request to Server A and the response is sent to Server B, then Server A is unintentionally attacking Server B. If the request is the same size as the response, then there’s no benefit to this attack. If the request is smaller than the response, and Server A sends Server B a bunch of unrequested data for every request from the camera, then you have a successful amplification attack. In the case of memcached, traffic can be amplified by more than 50,000 times, meaning that a small botnet can have a huge effect.

Memcached is a memory caching system whose primary use is to help large websites by caching data that would otherwise be stored in a database or API, so it really shouldn’t be publicly accessible anyway. And the solution is to turn off public-facing memcached over UDP, but the larger solution is to think about what things you are making available to the Internet, and how they can be used maliciously.

Bye Bye, Maplin

March 1, 2018 by Jenny List 97 Comments

Well, that was quick. Four days ago we mentioned that the British electronics retail chain Maplin was being offered for sale, and today it has been announced that no buyer has been found and the company is going into administration.

We dealt with all the nostalgia for what was roughly a British equivalent to Radio Shack in our previous post. Perhaps now it’s time to look beyond the jumpers-for-goalposts reminiscences about spaceships on the catalogues for a moment, and consider what this means for us in 2018.

It’s fairly obvious that a retail model for selling either electronic tat or components is no longer viable in an age of online ordering and availability of almost anything at knock-down prices for anyone prepared to wait for a packet from China. This applies on both sides of the Atlantic, but for British retailers, the killer combination of very high rents and local business taxes makes it particularly difficult. Maplin were extremely convenient when you needed a part immediately, but the universal reaction from Hackaday readers was that they were overpriced. It’s the same story that has cleared away numerous chains in other sectors, and the toxic view that retail property is still the goldmine it might have been in decades past is largely responsible.

Despite all that, there must still be some demand for electronic components at a retail level even if the economics no longer support a showroom model. Perhaps a trade counter operation might have better luck, it will be interesting to see whether suppliers such as RS Components or CPC expand their networks to try to capture that business. Whatever happens, we’ll keep you posted.