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Category Archives for "Security"

Notes on the Ashley-Madison dump

Ashley-Madison is a massive dating that claims 40 million users. The site is specifically for those who want to cheat on their spouse. Recently, it was hacked. Yesterday, the hackers published the dumped data.

It appears legit. I asked my twitter followers for those who had created accounts. I have verified multiple users of the site, one of which was a throw-away account used only on the site. Assuming my followers aren't lying, this means the dump is confirmed.

It's over 36-million accounts. That's not quite what they claim, but it's pretty close. However, glancing through the data, it appears that a lot of the accounts are bogus, obviously made up things for people who just want to look at the site without creating a "real" account.

It's heavily men. I count 28-million men to 5 million woman, according to the "gender" field in the database (with 2-million undetermined). However, glancing through the credit-card transactions, I find only male names.

It's full account information. This includes full name, email, and password hash as you'd expect. It also includes dating information, like height, weight, and so forth. It appears to contain addresses, as well as GPS coordinates. I suspect that Continue reading

DNS parser, meet Go fuzzer

Here at CloudFlare we are heavy users of the github.com/miekg/dns Go DNS library and we make sure to contribute to its development as much as possible. Therefore when Dmitry Vyukov published go-fuzz and started to uncover tens of bugs in the Go standard library, our task was clear.

Hot Fuzz

Fuzzing is the technique of testing software by continuously feeding it inputs that are automatically mutated. For C/C++, the wildly successful afl-fuzz tool by Michał Zalewski uses instrumented source coverage to judge which mutations pushed the program into new paths, eventually hitting many rarely-tested branches.

go-fuzz applies the same technique to Go programs, instrumenting the source by rewriting it (like godebug does). An interesting difference between afl-fuzz and go-fuzz is that the former normally operates on file inputs to unmodified programs, while the latter asks you to write a Go function and passes inputs to that. The former usually forks a new process for each input, the latter keeps calling the function without restarting often.

There is no strong technical reason for this difference (and indeed afl recently gained the ability to behave like go-fuzz), but it's likely due to the different ecosystems in which they Continue reading

Worth Reading: Access Control with Segmentation

When you couple software-defined segmentation with an intelligent planning and implementation methodology, you get active segmentation. This approach to segmentation allows network operators to effectively cordon off critical network assets and limit access appropriately with minimal disruption to normal business functions. via the Cloud Security Alliance

The post Worth Reading: Access Control with Segmentation appeared first on 'net work.

Worth Reading: Outsourcing

And my second point is even more important: know the allegiance of your outsourcer. The key issue with outsourcing IT is this — who does your IT staff work FOR? via Cringley


This is a point that many people don’t get — if all businesses are data businesses (and they are, despite the constant refrain I’ve heard throughout my career that “we don’t make technology, here, so…”), then all the data, and all the analysis you do on that data, is just like the famous Coke recipe.

Know data, know your business. No data, no business.

It’s really that simple. When will we learn — and take this idea seriously? And when will we realize this rule applies to the network as well as the data in many cases?

The post Worth Reading: Outsourcing appeared first on 'net work.

VLAN Bridging with FirePOWER

Although not immediately obvious, the FirePOWER Series 3 devices can do a form of IPS on a stick. This means that the capability described here should be available to the current appliance versions of the FirePOWER managed devices. The premise involves connecting broadcast domains (VLANs) to bring the managed device inline between the initiator and responder of a flow. Configuration is fairly straightforward but does have some caveats.

Caveats

  • Even though only a single port is required, a virtual switch must be configured (this cannot just be an inline pair)
  • BPDUs being bridged between VLANs are detected and will render the switchport(s) in an inconsistent state
  • The FirePOWER physical interface will not activate until it is also bound to a Virtual Switch

FirePOWER Bridge VLANsThe diagram shows two devices in the same VLAN (we will assume /24 for the configuration). The device on the top is in VLAN 100. The FirePOWER managed device bridges VLAN 100 to VLAN 101 and allows the two devices to communicate directly with one another. The connection to the FirePOWER device is a single 802.1q trunk.

Frames arriving on VLAN 100 will be processed and egress with a VLAN tag of 101. This configuration is similar to a Continue reading

Understanding Rowhammer

As I learned in my early days in electronics, every wire is an antenna. This means that a signal in any wire, given enough power, can be transmitted, and that same signal, in an adjacent wire, can be received (and potentially decoded) through electromagnetic induction (Rule 3 may apply). This is a major problem in the carrying of signals through a wire, a phenomenon known as cross talk. How do communications engineers overcome this? By observing that a signal carried along parallel wires at opposite polarities will cancel each other out electromagnetically. The figure below might help out, if you’re not familiar with this.

induction

This canceling effect of two waveforms traveling a pair of wires 180deg out of phase is why the twisted is in twisted pair, and why it’s so crucial not to unbundle too much wire when punching down a jack or connector. The more untwisted the wire there is, the less effective the canceling effect is around the punch down, and the more likely you are to have near end or far end crosstalk.

If you consider one row of memory in a chip one wire, and a second, adjacent row of memory in the Continue reading

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