c0d3 :: j0rg3

A collection of tips, tricks and snips. A proud Blosxom weblog. All code. No cruft.

Tue, 10 Jan 2017

[-] Auxiliary failed: Msf::OptionValidateError The following options failed to validate: RHOSTS.

Mucking about with a fresh copy of Kali brings to attention that it’s packaged with an Armitage that doesn’t correctly work.

I know what you’re thinking… Good. Type the commands into Msfconsole like a real man, y’uh lazy good-fer-naught! And, in practice, that was my immediate solution. But I can’t resist a good tinker when things are misbehaving.

I was anticipating that the problem would be thoroughly solved when I ixquicked it. That was partially correct. Surprised, however, when apt-get update && apt-get upgrade didn’t fix the issue. More surprised at the age of the issue. Most surprised that I could see lots of evidence that users have been plagued by this issue — but no clear work arounds were quickly found.

Guess what we’re doing today?

Okay. The issue is quite minor but just enough to be heartbreaking to the fledgling pentester trying to get a VM off the ground.

In brief, the owner of Armitage’s Github explains:

The MSF Scans feature in Armitage parses output from Metasploit’s portscan/tcp module and uses these results to build a list of targets it should run various Metasploit auxiliary modules against. A recent-ish update to the Metasploit Framework changed the format of the portscan/tcp module output. A patch to fix this issue just needs to account for the new format of the portscan/tcp module.

That is, a colon makes it into the input for the Msfconsole command to define RHOSTS. I.e.: set RHOSTS 172.16.223.150: - 172.16.223.150

An other kind coder tweaked the regex and submitted the patch and pull request, which was successfully incorporated into the project.

Sadly, things have stalled out there. So if this problem is crippling your rig, let’s fix it!

We just want a fresh copy of the project.
root@kali:~/armitage# git clone https://github.com/rsmudge/armitage

Cloning into ‘armitage’…
remote: Counting objects: 7564, done.
remote: Total 7564 (delta 0), reused 0 (delta 0), pack-reused 7564
Receiving objects: 100% (7564/7564), 47.12 MiB | 2.91 MiB/s, done.
Resolving deltas: 100% (5608/5608), done.

Kali is Debian-based and we’re going to need Apache Ant:
root@kali:~/armitage# apt-get install ant

Then, we’ll build our new fella:
root@kali:~/armitage# cd armitage
root@kali:~/armitage# ./package.sh

Buildfile: /root/test/armitage/build.xml

clean:

BUILD SUCCESSFUL
Total time: 0 seconds
Buildfile: /root/test/armitage/build.xml

init:
[mkdir] Created dir: /root/test/armitage/bin

compile:
[javac] Compiling 111 source files to /root/test/armitage/bin
[javac] depend attribute is not supported by the modern compiler
[javac] Note: /root/test/armitage/src/ui/MultiFrame.java uses or overrides a deprecated API.
[javac] Note: Recompile with -Xlint:deprecation for details.
[javac] Note: Some input files use unchecked or unsafe operations.
[javac] Note: Recompile with -Xlint:unchecked for details.

BUILD SUCCESSFUL
Total time: 2 seconds
Buildfile: /root/test/armitage/build.xml

init:

compile:

jar:
[unzip] Expanding: /root/test/armitage/lib/sleep.jar into /root/test/armitage/bin
[unzip] Expanding: /root/test/armitage/lib/jgraphx.jar into /root/test/armitage/bin
[unzip] Expanding: /root/test/armitage/lib/msgpack-0.6.12-devel.jar into /root/test/armitage/bin
[unzip] Expanding: /root/test/armitage/lib/postgresql-9.1-901.jdbc4.jar into /root/test/armitage/bin
[unzip] Expanding: /root/test/armitage/lib/javassist-3.15.0-GA.jar into /root/test/armitage/bin
[copy] Copying 4 files to /root/test/armitage/bin/scripts-cortana
[jar] Building jar: /root/test/armitage/armitage.jar
[jar] Building jar: /root/test/armitage/cortana.jar

BUILD SUCCESSFUL
Total time: 1 second
armitage/
armitage/readme.txt
armitage/teamserver
armitage/cortana.jar
armitage/armitage.jar
armitage/armitage-logo.png
armitage/armitage
armitage/whatsnew.txt
adding: readme.txt (deflated 55%)
adding: armitage.exe (deflated 49%)
adding: cortana.jar (deflated 5%)
adding: armitage.jar (deflated 5%)
adding: whatsnew.txt (deflated 65%)
armitage/
armitage/readme.txt
armitage/teamserver
armitage/cortana.jar
armitage/armitage.jar
armitage/armitage-logo.png
armitage/armitage
armitage/whatsnew.txt
Archive: ../../armitage.zip
inflating: readme.txt
inflating: armitage.exe
inflating: cortana.jar
inflating: armitage.jar
inflating: whatsnew.txt

And here, best I can guess from messages read, is where a lot of people are running into trouble. We have successfully produced our new working copy of armitage. However, it is in our own local directory and will not be run if we just enter the command: armitage

Let’s review how to figure out what we want to do about that.

First, we want to verify what happens when we run the command armitage.
root@kali:~/armitage# which armitage

/usr/bin/armitage

Good! Let’s check and see what that does!
root@kali:~/armitage# head /usr/bin/armitage

#!/bin/sh

cd /usr/share/armitage/
exec ./armitage “$@”

Almost there! It’s running /usr/share/armitage/armitage with whatever variables we’ve passed in. We’ll check that out.
root@kali:~/armitage# head /usr/share/armitage/armitage

#!/bin/sh
java -XX:+AggressiveHeap -XX:+UseParallelGC -jar armitage.jar $@

We have enough information to assemble a solution.

I trust that the people behind Kali and Armitage will get this corrected so I don’t want to suggest a solution that would replace the armitage command and prevent an updated version from running later. So, let’s just make a temporary replacement?

root@kali:~/armitage# echo -e '#!/bin/sh\njava -XX:+AggressiveHeap -XX:+UseParallelGC -jar ~/armitage/armitage.jar $@' > /usr/bin/tmparmitage

Hereafter, we can use the command ‘tmparmitage’ (either CLI or ALT-F2) to run our fresh version until things catch up.

And, of course, to save you the time, weary hacker:

Download here:
    armitage_quick_fix.sh


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Permalink: 20170110.armitage.not.working.in.kali

Mon, 02 Jan 2017

Securing a new server

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:

  • Set up SSH keys (scripted)
  • Disable password usage for root (scripted)
  • Install and configure IPset (scripted. details in next post)
  • Install and configure fail2ban
  • Install and configure PortSentry

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


    The tasks to be handled are:

  • Generate keys
  • Configure local SSH to use key
  • Transmit key to target server
  • Disable usage of password for ‘root’ account

  • 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:

    #!/bin/bash
    #configure variables
    remote_host="myserver.com"
    remote_user="j0rg3"
    remote_pass="thisisaratheraquitecomplicatedpasswordbatterystaple" # https://xkcd.com/936/
    local_user=`whoami`
    local_host=`hostname`
    local_date=`date -I`
    local_filename=~/.ssh/id_rsa@$remote_host

    #generate key without passphrase
    ssh-keygen -b 4096 -P "" -C $local_user@local_host-$local_date -f $local_filename

    #add reference to generated key to local configuration
    printf '%s\n' "Host $remote_host" "IdentityFile $local_filename" >> ~/.ssh/config

    #copy key to remote host
    sshpass -p $remote_pass ssh-copy-id $remote_user@$remote_host

    #disable password for root on remote
    ssh $remote_user@$remote_host "cp /etc/ssh/sshd_config /etc/ssh/sshd_config.bak && sed -i '0,/RE/s/PermitRootLogin yes/PermitRootLogin no/' /etc/ssh/sshd_config"

    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


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    Permalink: 20170102.securing.a.new.server

    Wed, 26 Jun 2013

    Terminal suddenly Chinese

    The other day, I was updating one of my systems and I noticed that it had decided to communicate with me in Chinese. Since I don’t know a lick of Chinese, it made for a clumsy exchange.

    It was Linux Mint (an Ubuntu variant), so a snip of the output from an ‘apt-get upgrade’ looked like this: terminal screen with Chinese characters

    I’m pretty sure I caused it — but there’s no telling what I was working on and how it slipped past me. Anyway, it’s not a difficult problem to fix but I imagine it could look like big trouble.

    So, here’s what I did:
    > locale

    The important part of the output was this:
    LANG=en_US.UTF-8
    LANGUAGE=zh_CN.UTF-8

    If you want to set your system to use a specific editor, you can set $EDITOR=vi and then you’re going to learn that some programs expect the configuration to be set in $VISUAL and you’ll need to change it there too.

    In a similar way, many things were using the en_US.UTF-8 set in LANG, but other things were looking to LANGUAGE and determining that I wanted Chinese.

    Having identified the problem, the fix was simple. Firstly, I just changed it in my local environment:
    > LANGUAGE=en_US.UTF-8

    That solved the immediate problem but, sooner or later, I’m going to reboot the machine and the Chinese setting would have come back. I needed to record the change somewhere for the system to know about it in the future.

    > vim /etc/default/locale

    Therein was the more permanent record, so I changed LANGUAGE there also, giving the result:

    LANG=en_US.UTF-8
    LANGUAGE=en_US.UTF-8
    LC_CTYPE=en_US.UTF-8
    LC_NUMERIC=en_US.UTF-8
    LC_TIME=en_US.UTF-8
    LC_COLLATE=”en_US.UTF-8”
    LC_MONETARY=en_US.UTF-8
    LC_MESSAGES=”en_US.UTF-8”
    LC_PAPER=en_US.UTF-8
    LC_NAME=en_US.UTF-8
    LC_ADDRESS=en_US.UTF-8
    LC_TELEPHONE=en_US.UTF-8
    LC_MEASUREMENT=en_US.UTF-8
    LC_IDENTIFICATION=en_US.UTF-8
    LC_ALL=

    And now, the computer is back to using characters that I (more-or-less) understand.


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    Permalink: 20130626.terminal.suddenly.chinese

    Thu, 13 Jun 2013

    Blogitechture continued… Simplify with Vim

    Last we were discussing the structure and design of your own CLI-centric blog platform, we had some crude methods of starting and resuming posts before publishing.

    Today, let’s explore a little more into setting up a bloging-friendly environment because we need to either make the experience of blogging easy or we’ll grow tired of the hassle and lose interest.

    We can reasonably anticipate that we won’t want to beleaguered with repetitious typing of HTML bits. If we’re going to apply paragraph tags, hyperlinks, codeblocks, etc. with any frequency, that task is best to be simplified. Using Vim as our preferred editor, we will use Tim Pope’s brilliant plug-ins ‘surround’ and ‘repeat’, combined with abbreviations to take away the tedium.

    The plug-ins just need dropped into your Vim plugin directory (~/.vim/plugin/). The directory may not exist if you don’t have any plug-ins yet. That’s no problem, though. Let’s grab the plugins:

    cd ~/.vim/
    wget "http://www.vim.org/scripts/download_script.php?src_id=19287" -O surround.zip
    wget "http://www.vim.org/scripts/download_script.php?src_id=19285" -O repeat.zip

    Expand the archives into the appropriate directories:

    unzip surround.zip
    unzip repeat.zip

    Ta-da! Your Vim is now configured to quickly wrap (surround) in any variety of markup. When working on a blog, you might use <p> tags a lot by putting your cursor amid the paragraph and typing yss<p>. The plug-in will wrap it with opening and closing paragraph tags. Move to your next paragraph and then press . to repeat.

    That out of the way, let’s take advantage of Vim’s abbreviations for some customization. In our .vimrc file, we can define a few characters that Vim will expand according to their definition. For example, you might use:
    ab <gclb> <code class="prettyprint lang-bsh linenums:1">
    Then, any time you type <gclb> and bress <enter>, you’ll get:
    <code class="prettyprint lang-bsh linenums:1">

    The next time that we take a look at blogitecture, we will focus on making the posts convenient to manage from our CLI.


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    Permalink: 20130613.blogitechture.continued

    Thu, 23 May 2013

    GNU Screen: Roll your own system monitor

    Working on remote servers, some tools are practically ubiquitous — while others are harder to come by. Even if you’ve the authority to install your preferred tools on every server you visit, it’s not always something you want to do. If you’ve hopped on to a friend’s server just to troubleshoot a problem, there is little reason to install tools that your friend is not in the habit of using. Some servers, for security reasons, are very tightly locked down to include only a core set of tools, to complicate the job of any prying intruders. Or perhaps it is a machine that you normally use through a graphical interface but on this occasion you need to work from the CLI.

    These are very compelling reasons to get comfortable, at the very least, with tools like Vim, mail, grep and sed. Eventually, you’re likely to encounter a situation where only the classic tools are available. If you aren’t competent with those tools, you’ll end up facing the obstacle of how to get files from the server to your local environment where you can work and, subsequently, how to get the files back when you’re done. In a secured environment, this may not be possible without violating protocols.

    Let’s take a look at how we can build a makeshift system monitor using some common tools. This particular configuration is for a server running PHP, MySQL and has the tools Htop and mytop installed. These can easily be replaced with top and a small script to SHOW FULL PROCESSLIST, if needed. The point here is illustrative, to provide a template to be modified according to each specific environment.

    (Note: I generally prefer tmux to Gnu Screen but screen is the tool more likely to be already installed, so we’ll use it for this example.)

    We’re going to make a set of windows, by a configuration file, to help us keep tabs on what is happening in this system. In so doing, we’ll be using the well-known tools less and watch. More specifically, less +F which tells less to “scroll forward”. Other words, less will continue to read the file making sure any new lines are added to the display. You can exit this mode with CTRL+c, search the file (/), quit(q) or get back into scroll-forward mode with another uppercase F.

    Using watch, we’ll include the “-d” flag which tells watch we want to highlight any changes (differences).

    We will create a configuration file for screen by typing:

    > vim monitor.screenrc

    In the file, paste the following:

    # Screen setup for system monitoring
    # screen -c monitor.screenrc
    hardstatus alwayslastline
    hardstatus string '%{= kG}[ %{G}%H %{g}][%= %{=kw}%?%-Lw%?%{r}(%{W}%n*%f%t%?(%u)%?%{r})%{w}%?%+Lw%?%?%= %{g}][%{B}%Y-%m-%d %{W}%c %{g}]'

    screen -t htop 0 htop
    screen -t mem 1 watch -d "free -t -m"
    screen -t mpstat 2 watch -d "mpstat -A"
    screen -t iostat 3 watch -d "iostat"
    screen -t w 4 watch -d "w"
    screen -t messages 5 less +F /var/log/messages
    screen -t warn 6 less +F /var/log/warn
    screen -t database 7 less +F /srv/www/log/db_error
    screen -t mytop 8 mytop
    screen -t php 9 less +F /srv/www/log/php_error

    (Note: -t sets the title, then the window number, followed by the command running in that window)

    Save the file (:wq) or, if you’d prefer, you can grab a copy by right-clicking and saving this file.

    Then we will execute screen using this configuration, as noted in the comment:

    > screen -c monitor.screenrc

    Then you can switch between windows using CTRL+a, n (next) or CTRL+a, p (previous).

    I use this technique on my own computers, running in a TTY different from the one used by X. If the graphical interface should get flaky, I can simply switch to that TTY (e.g., CTRL+ALT+F5) to see what things are going on — and take corrective actions, if needed.


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    Permalink: 20130523.gnu.screen.system.monitor

    Mon, 13 May 2013

    Zsh and hash

    Documentation for this one seems a bit hard to come by but it is one of the things I love about Zsh.

    I’ve seen many .bashrc files that have things like:
    alias www='cd /var/www'
    alias music='cd /home/j0rg3/music'

    And that’s a perfectly sensible way to make life a little easier, especially if the paths are very long.

    In Zsh, however, we can use the hash command and the shortcut we get from it works fully as the path. Other words, using the version above, if we want to edit ‘index.html’ in the ‘www’ directory, we would have to issue the shortcut to get there and then edit the file, in two steps:
    > www
    > vim index.html

    The improved version in .zshrc would look like:
    hash www=/var/www
    hash -d www=/var/www

    Then, at any time, you can use tilde (~) and your shortcut in place of path.
    > vim ~www/index.html

    Even better, it integrates with Zsh’s robust completions so you can, for example, type cd ~www/ and then use the tab key to cycle through subdirectories and files.

    On this system, I’m using something like this:
    (.zshrc)
    hash posts=/home/j0rg3/weblog/posts
    hash -d posts=/home/j0rg3/weblog/posts

    Then we can make a function to create a new post, to paste into .zshrc. Since we want to be able to edit and save, without partial posts becoming visible, while we are working, we’ll use an extra .tmp extension at the end:
    post() { vim ~posts/`date +%Y-%m`/`date +%Y%m%d`.$1.txt.tmp }

    [ In-line date command unfamiliar? See earlier explanation ]

    But, surely there is going to be a point when we need to save a post and finish it later. For now, let’s assume that only a single post will be in limbo at any time. We definitely don’t want to have to remember the exact name of the post — and we don’t want to have hunt it down every time.

    We can make those things easier like this:
    alias resume="vim `find ~posts/ -name '*.txt.tmp'`"

    Now, we can just enter resume and the system will go find the post we were working on and open it up for us to finish. The file will need the extension renamed from .txt.tmp to only .txt to publish the post but, for the sake of brevity, we’ll think about that (and having multiple posts in editing) on another day.


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    Permalink: 20130513.zsh.and.hash

    Tue, 07 May 2013

    Welcome, traveler.

    Thanks for visiting my little spot on the web. This is a Blosxom ‘blog which, for those who don’t know, is a CGI written in Perl using the file-system (rather than a database).

    To the CLI-addicted, this is an awesome little product. Accepting, of course, that you’re going to get under the hood if you’re going to make it the product you want. After some modules and hacking, I’m pleased with the result.

    My posts are just text files, meaning I start a new one like: vim ~posts/`date +%Y%m%d`.brief.subject.txt

    Note: the back-ticks (`) tell the system that you want to execute the command between ticks, and dynamically insert its output into the command. In this case, the command date with these parameters:
    1. (+) we’re going to specify a format
    2. (%Y) four-digit year
    3. (%m) two-digit month
    4. (%d) two-digit day
    That means the command above will use Vim to edit a text file named ‘20130507.brief.subject.txt’ in the directory I have assigned to the hash of ‘posts’. (using hash this way is a function of Zsh that I’ll cover in another post)

    In my CLI-oriented ‘blog, I can sprinkle in my own HTML or use common notation like wrapping a word in underscores to have it underlined, forward-slashes for italics and asterisks for bold.

    Toss in a line that identifies tags and, since Perl is the beast of Regex, we pick up the tags and make them links, meta-tags, etc.

    Things here are likely to change a lot at first, while I twiddle with CSS and hack away at making a Blosxom that perfectly fits my tastes — so don’t be too alarmed if you visit and things look a tad wonky. It just means that I’m tinkering.

    Once the saw-horses have been tucked away, I’m going to take the various notes I’ve made during my years in IT and write them out, in a very simple breakdown, aimed at sharing these with people who know little about how to negotiate the command line. The assumption here is that you have an interest in *nix/BSD. If you’ve that and the CLI is not a major part of your computing experience, it probably will be at some point. If you’re working on systems remotely, graphical interfaces often just impede you.

    Once you’ve started working on remote machines, the rest is inevitable. You can either remember how to do everything two ways, through a graphical interface and CLI — or just start using the CLI for everything.

    So let’s take a little journey through the kinds of things that make me love the CLI.


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    Permalink: 20130507.greetings