Cackalacky Con This Week!

Did you miss the last 3-day weekend? Well, I think we have here a reason for you to make it happen!

If you live or are near the NC Triangle (Raleigh, Durham, Chapel Hill) this week, on Friday May 5th the Cackalacky Con conference begins at the DoubleTree by Hilton Hotel Raleigh-Durham Airport at Research Triangle Park. It goes on until May 7th and will contain lots of events (besides the talks) such as CTF, hardware stuff, lockpicking, and much more.

Videos from previous conferences such as this one
can found at the CackalackyCon youtube chanel.

I should warn you that I will be giving a talk. So, if you happen to land on it, please act terrified.

Still, lookie at the fancy badge I got!

Passwordless authentication and MFA

There is a push to stop using passwords to authenticate into systems. In 2020 Microsoft announced in its blog that it hopes to make its customers go passwordless in 2021. They plan on achieving it by using FIDO2 security keys such as Yubikey, (smart) phone-based sign-in tools such as the Microsoft and the Google Authenticators, and biometric tools such as fingeprint authentication. They are not alone; Apple and Google have also working on that not only to login to their devices but also websites and apps.

Here is the fun part: those solutions are being pushed as "you only need to pick one of them and you are secure!" Want to login to your phone? Just show your face! Get into your house? Stick your finger at it! How about your bank? Click on something in your phone! So, what it is doing is replacing one form of authentication -- passwords (boo! Hiss!) with a passwordless solution.

What is wrong with this picture?

Does anyone remember Multi Factor Authentication (MFA)? The idea is to use more than one form of authentication so if one is compromised your account is still not compromised. That was usually done by using one authentication from each of the following groups:

• Something you know. Like a password.
• Something you have. Like a badge or a Yubikey.
• Something you are. Like your Iris.

The so-called passwordless solutions being mentioned started their lives as a second factor in the MFA design, but now they are being pushed as the only form of authentication required. That implies those companies do think they are very strong against attacks to be used on their own.

When the FBI and the CISA announced MFA can be hacked, they are really talking about the secondary, passwordless, authentication of the MFA process, password being the primary (which has its own issues, but we are talking here about increasing the odds that the multiple authentications will not all be compromised at the same time). is not a panacea. Like everything else, passwordless authentication can be hacked;see the Uber data breach.

Bottom line

Passwords can be compromised. Passwordless authentication can also be compromised. There is no panacea. Both together should be a bit more secure than each of them. If you are bound not to have passwords at all, get two distinct MFA systems.

As the old say goes, Two is One, One is None.

Github updating its ssh keys

Today I learned that the Microsoft-owned Github decided to update its RSA SSH host host key but did not explain its reasoning. Why would it go through all of this trouble? Usually when a company does that, it is their way to cover that they were hacked or were compromised in some other way. That is not what is written in their blog, so we will have to wait for this to unfold.

"What does that mean to companies and developers depending on that?" Well,

• If you created a SSH RSA keypair to authenticate against github -- so you can git push and git pull your repos without entering your password -- you probably wants to consider creating a new pair, deleting the old one, and using the new one. Ideally, this may also be an excuse to switch to an ECDSA-derived key such as ed25519 if you are able to. Sometimes this is hard because you may be dealing with a host that does not support that... not that have ever happened to me.
• If you have received the github RSA pub host key, which was added to your .ssh/known_hosts (if you are using Linux, OSX, and some UNIX variation) file, you will need to delete that entry and get github feed you a new one. Of course, you want to ensure you are getting the proper github key, not one from someone impersonating it.
• If you use Windows, well, let me get back at you on that later.

Now some developers will argue that relying on known_hosts has caused more failures of working software than preventing faked host access since SSH was originally written. Their proposed way to deal with that is to tell ssh not to check the validity of the host key. In Linux, OSX, and other UNIX versions that would mean to disable that in ~/.ssh/config. If you want to disable the Key checking to all ssh connections, you could do something like (the boldface lines are the most important parameters)

    Host *
           UserKnownHostsFile /dev/null
           StrictHostKeyChecking no
           LogLevel error

While I understand that the above is a clever way of stopping suck pesky keys from hampering your style, disabling security for the sake of convenience is never a good solution. The more time-consuming solution is to remove the offending keys in ~/.ssh/known_hosts so you can ensure you are getting the right key, not a key impersonating the site you want to connect to, which in this case is github.

Fun fact: given that I saw the following message, I think they are not only changing the RSA key:

Warning: the ECDSA host key for 'github.com' differs 
from the key for the IP address '140.82.121.3'

TDIL Slack uses let's encrypt

This morning I was going to login to slack from the command line and saw the following message:

┌───────────────────────┤SSL Certificate Verification├────────────────────────┐
│Accept certificate for slack.com?                                            │
│                                                                             │
│The certificate for slack.com could not be validated.                        │
│                                                                             │
│The certificate is not trusted because no certificate that can verify it is  │
│currently trusted.                                                           │
│                                                                             │
│                ┌────────┐ ┌────────┐ ┌──────────────────────┐               │
│                │ Accept │ │ Reject │ │ _View Certificate... │               │
│                └────────┘ └────────┘ └──────────────────────┘               │
└─────────────────────────────────────────────────────────────────────────────┘

Let's probulate a bit:

┌──────────────────────────┤Certificate Information├──────────────────────────┐
│Certificate Information                                                      │
│                                                                             │
│Common name: slack.com                                                       │
│                                                                             │
│Issued By: CN=R3,O=Let's Encrypt,C=US                                        │
│                                                                             │
│Fingerprint (SHA1): 76:bc:49:94:88:fa:90:d6:59:3c:04:0d:81:81:67:58:35:ce:a0 │
│:d5                                                                          │
│                                                                             │
│Activation date: Thu Mar  2 07:32:27 2023                                    │
│                                                                             │
│Expiration date: Wed May 31 07:32:26 2023                                    │
│                                                                             │
│SHA256: 25:6f:90:6b:16:b5:1b:4a:27:27:55:19:9d:1a:76:61:11:b0:d2:7c:6b:b6:b6 │
│:36:48:ac:c5:5a:6c:92:8f:80                                                  │
│                                                                             │
│                     ┌─────────────────────────┐ ┌───────┐                   │
│                     │ View Issuer Certificate │ │ Close │                   │
│                     └─────────────────────────┘ └───────┘                   │
└─────────────────────────────────────────────────────────────────────────────┘

So,

• They are using Let's Encrypt
• The certificate is renewed every month
• The new certificate is not enabled yet (it is 7:20h right now)

What else can we find?

┌────┤Certificate Information├────┐icate Verification├────────────────────────┐
│                                 │                                           │
│Unable to find Issuer Certificate│                                           │
│              ┌────┐             │d not be validated.                        │
│              │ OK │             │                                           │
│              └────┘             │ause no certificate that can verify it is  │
└─────────────────────────────────┘                                           │
│                                                                             │
│                ┌────────┐ ┌────────┐ ┌──────────────────────┐               │
│                │ Accept │ │ Reject │ │ _View Certificate... │               │
│                └────────┘ └────────┘ └──────────────────────┘               │
└─────────────────────────────────────────────────────────────────────────────┘

Very interesting. How about from the command line?

user@desktop:~$ echo ''|openssl s_client -connect slack.com:443 | openssl \
x509 -noout -enddate -startdate
depth=2 C = US, O = Internet Security Research Group, CN = ISRG Root X1
verify return:1
depth=1 C = US, O = Let's Encrypt, CN = R3
verify return:1
depth=0 CN = slack.com
verify return:1
DONE
notAfter=May 31 07:32:26 2023 GMT
notBefore=Mar  2 07:32:27 2023 GMT
user@desktop:~$ 

Now you too know!

Splitting Kali VM's partitions, or why I do not like the default (Desktop) Linux partitioning scheme

WARNING:

1. Just because I am mentioning Debian/Ubuntu Linux in my rant, it does not mean the RedHat-derived distros are guilty free. In fact, I am looking at you, Fedora. The reason I am mentioning the Debian-derived distros are because
   • Kali is built on Debian.
   • I usually run an ubuntu derivative desktop Linux in my laptop.
   The principle of my rant still remains, and is really not as security- or privacy-oriented as the other blog posts.

2. This post will be a bit more technical than the usual, and will not take the time to explain certain things or this will become a book. There are other shows to watch.

Like many, I have Kali Linux installed in a virtual machine I use for things. Given the requirements in their install page, which said

On the higher end, if you opt to install the default Xfce4 desktop and the kali-linux-default metapackage, you should really aim for at least 2 GB of RAM and 20 GB of disk space.

I thought it was fine building a vm following those specs to run Kali. The memory I was not that concerned because adding more to a KVM vm guest is pretty easy (provided you have some to spare). But we are not talking about how to build a Kali vm guest; there are a lot of blogs and websites claiming to provide "everything you need to know about" how to do the deed, where the everything keyword means "we will rush through it but pretend we are experts." Am I being an arrogant bastard? Quite possibly, so let's jump to an example.

The problem

I am kinda of particular about the partition layout I use. In fact, let's take a quick look at my desktop (where I am typing this right now):

Device       Start       End   Sectors  Size Type
/dev/sda1     2048   2099199   2097152    1G Linux filesystem
/dev/sda2  2099200   3147775   1048576  512M EFI System
/dev/sda3  3147776 212862975 209715200  100G Linux LVM

Those whith sharp eye noticed I have made the partition for that FAT offspring, EFI, which is way larger than needed. Call me lazy. What you may not be aware is that this is a 1TB (in Subway sandwich math; it really is 931.53 (GiB) if we use powers of 2 just like C'Thulu intended us to do) drive. In other words, I did not create a partition that ranges the entire disk as I found to be the default in most Linux installations, specially desktops. You know, because everyone installs the OS such that to use the entire drive. Who would do anything else?

Next you will notice there are 3 partitions:

• /dev/sda1, which is the /boot
• /dev/sda2, which is the already-mentioned EFI
• /dev/sda3, which is a LVM physical volume for everything else.

I like this format since it works for both MBR and GPT styles of partition tables: I can have 3 "primary" partitions in the older MBR style without breaking a sweat. Consistency is good. Now we can talk about the partition for everything else: since it is a lvm physical volume, I then split it up into separate partitions and assign them to some directories, namely (vg name changed to protect the innocent. However, I chose not to sanitize the name of the swap partition before posting it here)

LV       VG     Attr       LSize  Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
home     desktop -wi-ao---- 30.00g                                                    
root     desktop -wi-ao----  4.00g                                                    
swaphole desktop -wi-ao---- 10.00g                                                    
usr      desktop -wi-ao---- 11.00g                                                    
var      desktop -wi-ao----  6.00g

At this point in time someone on the back of the room will shout "Heresy! Separating partitions in their own filesystems is an outdated concept! You should use a single partition! On the top of that you are not using the entire volume group!" Hey, I said I was an arrogant bastard earlier on. Besides, this is my computer. Fear not, for the next paragraphs will justify the heresy claim even better.

For my kali vm guest, I started with a 20GB virtual disk based on the installation page's notes as mentioned above. At the time I decided to let it set the partition table the way it wanted, and here it is

Device     Boot    Start      End  Sectors  Size Id Type
/dev/vda1  *        2048 39942143 39940096   19G 83 Linux
/dev/vda2       39944190 41940991  1996802  975M  5 Extended
/dev/vda5       39944192 41940991  1996800  975M 82 Linux swap / Solaris

It created two primary partitions: one for the OS and one that is there just to create an extended partition to put the swap. Riddle me this: why in a 2-partition drive do we need to use the MBT extended partition? Are we close to running out of partitions that we need to reach for that gimmick? Before you answer, remember my 3-partition layout works fine with that style of partition table. Bottom line is the default installation created two partitions to do the job of a single way. Brilliant!

Let's get to where the fun really is: realistically 20GB for Kali is very limiting at best. If you start colleting a few (sizeable) pcaps or grab a binary file or two to inspect (temp files do add up), you may have maxed it out. That happened to me, combined with forgetting to periodically clean the package cache and getting some bits and bobs for metasploit. And all of this happened when I was on the clock.

Brilliant!

If we use the partition layout I like, I would then resize the drive and extend the PV and then the VG. problem solved. Not so here, thanks to that extended partition that is sitting right in the way. The best I could do was to increase the size of the drive as before, then add another partition at its end:

Device     Boot    Start      End  Sectors  Size Id Type
/dev/vda1  *        2048 39942143 39940096   19G 83 Linux
/dev/vda2       39944190 41940991  1996802  975M  5 Extended
/dev/vda3       41940992 62914559 20973568   10G 83 Linux
/dev/vda5       39944192 41940991  1996800  975M 82 Linux swap / Solaris

Since I did not use lvm on this setup, I would have to decide which directory to move to the new partition, which then leads us to the problem the default install wanted to avoid in the first place. And, we now have a drive whose partition table looks convoluted (the adjective I had in my mind was different, but I decided to find a more polite one) and hard to maintain. At this point the only logical thing to do is blow everything up and redo it with a larger disk.

Brilliant!

And this kind of shenaningans are not only limited to the Kali install; installing the OS in my latop has been even more frustrating, but I will save that to another post.

Is there a better way to solve this problem? Well, it requires some heretic maneuvers, which is why I like it.

The solution

By now we should accept we need to move at least one directory tree out of /dev/vda1 I decree it shall be /home, but where should we put it? I will not extend /dev/vda and add another partition there, so what if we create a second virtual drive? Some of the reasons:

• It moves a directory tree that can become quite large out of the root drive.
• Even if you did not use a LVM, which in this case I did not, you can still resize that drive and that partition, without much work.
• If you need to move files between your kali vm guest and the host, you can shoot the vm down and then mount this second disk. This way there is no programs -- malicious or not -- running in the vm gues and you do not need to create a (exploitable) network connection between the host and guest.
• If you decide to blow up you kali install, your work is preserved.
• You can handle /home to somebody else without worrying about compromising your kali passwords.

Enough talk. Here are the steps. I will try to make them as generic as I can but understand most of the time I not only use KVM but also do it from the command line, and on a Linux box. So, if you are doing this from a Mac or a Windows computer, the commands will differ from mine. I am also rushing through the permissions since I assume you know how to set them up so your disk image can be read by your vm. You have been warned.

1. Shut the vm guest down. Yes, I know how to add a drive to a running vm -- I do that all the time when I have to do forensics -- but it is much easier and safer if you do not need to upset the virtual machine.
2. Create the virtual drive you will use for /home. How big? Up to you. The one I created for my kali vm is 20GB (as close to real disk size units as I can). Remember to put it in a sane location, be it inside the directory where the other vm files are, a place such as /home/user/.local/share/libvirt/images/, or some other secure place. For this example I am using /export/vm.

   user@vmhost:~# VMNAME=kalinuts
   user@vmhost:~# qemu-img create -f qcow2 /export/vm/${VMNAME}.qcow2 20G
   Formatting '/export/vm/kalinuts.qcow2', fmt=qcow2 cluster_size=65536 
   extended_l2=off compression_type=zlib size=21474836480 lazy_refcounts=off 
   refcount_bits=16
   user@vmhost:~# 

   Most people will use qcow2 in KVM because its a sparse disk image (most may not be aware of that) and it is the default (duh!). If you use VirtualBox or VMWare or whatever, chances are the default disk format (vdi) will work fine; check if it can be resized to be sure. If not, find the virtual disk type that can.

   Remember we said it is a sparse disk image? Here is proof:

   user@vmhost:~# ls -lh /export/vm/kalinuts.qcow2 
   -rw-r--r-- 1 user user 193K Mar  2 09:51 /export/vm/kalinuts.qcow2
   user@vmhost:~# 

3. Format the drive. Note that I did not say partition it.

   user@vmhost:~# mkfs.ext4 /export/vm/kalinuts.qcow2 
   mke2fs 1.46.2 (28-Feb-2021)
   
   Filesystem too small for a journal
   Discarding device blocks: done                            
   Creating filesystem with 192 1k blocks and 24 inodes
   
   Allocating group tables: done                            
   Writing inode tables: done                            
   Writing superblocks and filesystem accounting information: done
   
   user@vmhost:~# 

4. Not needed step: I mounted it just to show I can mount the drive from the vm host side, since this is one of the claims I made ealier on.

   root@vmhost:~# mount /export/vm/kalinuts.qcow2 /mnt
   root@vmhost:~# df -h|grep /mnt
   /dev/loop0                            183K   14K  157K   9% /mnt
   root@vmhost:~# ls /mnt
   lost+found
   root@vmhost:~# 

   Don't forget to unmount it before going to the next step.

5. Now add the drive to your kali/whatever vm. If you have a GUI, click on things. For KVM, there is also a GUI and some command line ways. The bottom line is that you want something like this in your devices session (adjust path and target device names to fit your local setup):

   <disk type='file' device='disk'>
      <driver name='qemu' type='qcow2' iommu='on'/>
      <source file='/export/vm/kalinuts.qcow2'/>
      <target dev='vdb' bus='virtio'/>
   </disk>

   When you save the config file, it will autofill the rest of the info such as where in the kali vm pci chain this disk will reside.

6. Boot the kali vm and verify it can see the drive. I use dmesg or either fdisk -l or parted -l to see if it was mounted.
7. While in the kali vm, become root user so you stop messing with /home
8. Mount the new drive somewhere such as /mnt
9. Move the contents from /home to /mnt. Remember: if this does not work you still have the files so you can move them back. Also, we are doing all this work to move all the junk in /home off the boot disk.
10. Unmont the new drive from /mnt and configure the /etc/fstab so it will mount on /home (bolt line in the /etc/fstab file shown below)

    # /etc/fstab: static file system information.
    #
    # Use 'blkid' to print the universally unique identifier for a
    # device; this may be used with UUID= as a more robust way to name devices
    # that works even if disks are added and removed. See fstab(5).
    #
    # systemd generates mount units based on this file, see systemd.mount(5).
    # Please run 'systemctl daemon-reload' after making changes here.
    #
    #                
    # / was on /dev/vda1 during installation
    UUID=iisaw-something-under-my-armpit /               ext4    errors=remount-ro 0       1
    # swap was on /dev/vda5 during installation
    UUID=do-you-like-vogon-poetry none            swap    sw              0       0
    /dev/sr0        /media/cdrom0   udf,iso9660 user,noauto     0       0
    /dev/vdb        /home           ext4    defaults        0       2
    

11. Reboot it and verify it is using the new drive. If not, correct the issue.
12. Get a cold beer.

What about resizing the drive?

1. Shut the vm down again.
2. Resize the drive, maybe adding another 10G

   qemu-img resize /export/vm/kalinuts.qcow2 +10G

3. Boot the vm.
4. From inside the vm, resize the partition. Since I used ext4, I can do

   resize2fs /dev/vdb

5. Enjoy the larger /home.

Fun fact: I normally use raw drives, but most of the steps are the same; I just need to have a different <drive></drive> definition.

Rehoming some phishes

Quick notice: I will be moving my phishing posts to a new location, phishphillet.com. In fact, if you go there you will find some of the old posts I had here and a few new ones; it is a work in progress!

Officially the reasons are

• It is (hopefully) easier to find my phishing posts; they are all in their own domain.
• People looking for phishing adventures will not have to wade through the other blog posts.
• I can then ask for people to send me their phishing emails. This is very important since phishers do not seem to like me.

Now the main reason is because I am considering moving this very blog to another location and am trying not only hosting options out but also software. Testing things is nice, but "testing" as a production environment can show weanesses I was not aware of.

I will document and post later the (mis)adventures on setting that up in case it may be useful to others. For now on, if you want some phishing, go to phishphillet.com.

Help the Diana Initiative

We interrupt our normal shenanigans for a serious post. For those who have not heard of them, first of all do not confuse it with NATO's Defence Innovation Accelerator for the North Atlantic (DIANA), which was created (and appropriated the name) in 2021. The Real Diana Initiative is a 501(c)(3) non-profit organization was founded in 2016 and runs a security conference focused on women, diversity, and inclusion in Las Vegas (for reference, DEFCON 31 takes place on Aug 10-13 2023, BSidesLV 8-9 2023, and the Diana Initiative on August 7, 2023). So, if you play your cards right you will have a full week of nothing but security and privacy talks!

Here are some videos from last year's conference:

And now the bad news, which with your help can become but an example of the community rising to the occasion: recently all the gear they use in their event was stolen including their Weller soldering irons which are used in their workshops, and now they need help. If you can donate gear, little pieces of green paper, or become a sponsor, do contact them either through their website or Twitter account. They are already considering canning their CTF; let's see if that is that is the worst thing they will have to sacrifice.

Reason I am making this post is to ask those who read my blog to see if they can help in any way. If you can, thank you! If you cannot, just pass the word to others.