Wednesday, July 26, 2017

Slowloris all the things

At DEFCON, some researchers are going to announce a Slowloris-type exploit for SMB -- SMBloris. I thought I'd write up some comments.

Sunday, July 23, 2017

Defending anti-netneutrality arguments

Last week, activists proclaimed a "NetNeutrality Day", trying to convince the FCC to regulate NetNeutrality. As a libertarian, I tweeted many reasons why NetNeutrality is stupid. NetNeutrality is exactly the sort of government regulation Libertarians hate most. Somebody tweeted the following challenge, which I thought I'd address here.

The links point to two separate cases.
  • the Comcast BitTorrent throttling case
  • a lawsuit against Time Warning for poor service
The tone of the tweet suggests that my anti-NetNeutrality stance cannot be defended in light of these cases. But of course this is wrong. The short answers are:

  • the Comcast BitTorrent throttling benefits customers
  • poor service has nothing to do with NetNeutrality

The long answers are below.

Saturday, July 08, 2017

Burner laptops for DEF CON

Hacker summer camp (Defcon, Blackhat, BSidesLV) is upon us, so I thought I'd write up some quick notes about bringing a "burner" laptop. Chrome is your best choice in terms of security, but I need Windows/Linux tools, so I got a Windows laptop.

I chose the Asus e200ha for $199 from Amazon with free (and fast) shipping. There are similar notebooks with roughly the same hardware and price from other manufacturers (HP, Dell, etc.), so I'm not sure how this compares against those other ones. However, it fits my needs as a "burner" laptop, namely:
  • cheap
  • lasts 10 hours easily on battery
  • weighs 2.2 pounds (1 kilogram)
  • 11.6 inch and thin
Some other specs are:
  • 4 gigs of RAM
  • 32 gigs of eMMC flash memory
  • quad core 1.44 GHz Intel Atom CPU
  • Windows 10
  • free Microsoft Office 365 for one year
  • good, large keyboard
  • good, large touchpad
  • USB 3.0
  • microSD
  • WiFi ac
  • no fans, completely silent
There are compromises, of course.
  • The Atom CPU is slow, thought it's only noticeable when churning through heavy webpages. Adblocking addons or Brave are a necessity. Most things are usably fast, such as using Microsoft Word.
  • Crappy sound and video, though VLC does a fine job playing movies with headphones on the airplane. Using in bright sunlight will be difficult.
  • micro-HDMI, keep in mind if intending to do presos from it, you'll need an HDMI adapter
  • It has limited storage, 32gigs in theory, about half that usable.
  • Does special Windows 10 compressed install that you can't actually upgrade without a completely new install. It doesn't have the latest Windows 10 Creators update. I lost a gig thinking I could compress system files.

Copying files across the 802.11ac WiFi to the disk was quite fast, several hundred megabits-per-second. The eMMC isn't as fast as an SSD, but its a lot faster than typical SD card speeds.

The first thing I did once I got the notebook was to install the free VeraCrypt full disk encryption. The CPU has AES acceleration, so it's fast. There is a problem with the keyboard driver during boot that makes it really hard to enter long passwords -- you have to carefully type one key at a time to prevent extra keystrokes from being entered.

You can't really install Linux on this computer, but you can use virtual machines. I installed VirtualBox and downloaded the Kali VM. I had some problems attaching USB devices to the VM. First of all, VirtualBox requires a separate downloaded extension to get USB working. Second, it conflicts with USBpcap that I installed for Wireshark.

It comes with one year of free Office 365. Obviously, Microsoft is hoping to hook the user into a longer term commitment, but in practice next year at this time I'd get another burner $200 laptop rather than spend $99 on extending the Office 365 license.

Let's talk about the CPU. It's Intel's "Atom" processor, not their mainstream (Core i3 etc.) processor. Even though it has roughly the same GHz as the processor in a 11inch MacBook Air and twice the cores, it's noticeably and painfully slower. This is especially noticeable on ad-heavy web pages, while other things seem to work just fine. It has hardware acceleration for most video formats, though I had trouble getting Netflix to work.

The tradeoff for a slow CPU is phenomenal battery life. It seems to last forever on battery. It's really pretty cool.


A Chromebook is likely more secure, but for my needs, this $200 is perfect.

Saturday, July 01, 2017

Yet more reasons to disagree with experts on nPetya

In WW II, they looked at planes returning from bombing missions that were shot full of holes. Their natural conclusion was to add more armor to the sections that were damaged, to protect them in the future. But wait, said the statisticians. The original damage is likely spread evenly across the plane. Damage on returning planes indicates where they could damage and still return. The undamaged areas are where they were hit and couldn't return. Thus, it's the undamaged areas you need to protect.

This is called survivorship bias.

Many experts are making the same mistake with regards to the nPetya ransomware. 

Thursday, June 29, 2017

NonPetya: no evidence it was a "smokescreen"

Many well-regarded experts claim that the not-Petya ransomware wasn't "ransomware" at all, but a "wiper" whose goal was to destroy files, without any intent at letting victims recover their files. I want to point out that there is no real evidence of this.

Saturday, June 24, 2017

A kindly lesson for you non-techies about encryption

The following tweets need to be debunked:

The answer to John Schindler's question is:
every expert in cryptography doesn't know this
Oh, sure, you can find fringe wacko who also knows crypto that agrees with you but all the sane members of the security community will not.

Wednesday, June 14, 2017

Notes on open-sourcing abandoned code

Some people want a law that compels companies to release their source code for "abandoned software", in the name of cybersecurity, so that customers who bought it can continue to patch bugs long after the seller has stopped supporting the product. This is a bad policy, for a number of reasons.