Buffer Overflow Linux Worksheet

8/18/2019Run SEED VM on VirtualBox
User Manual
Table of Contents
How to Use Virtualbox to Run SEED Ubuntu VM
Appendix A: Creating Multiple VMs
Appendix B: Network Configuration
Appendix C: Taking Snapshots of VM
Appendix D: Creating Shared Folder
The account information
You will primarily use the following account:
• User ID: seed
• Password: dees
You normally don’t need to log into the root account:
• User ID: root
• Password: seedubuntu
Wenliang (Kevin) Du
SYRACUSE UNIVERSITY
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How to use VirtualBox to Run SEED Ubuntu VM?
Install the free VirtualBox software first. We recommend Version 6.0.4 (please stay away from the
newer versions, as they still have some issues with our VM).
Step 1: Create a New VM in VirtualBox
Click this button
Step 2: Provide a Name and Select the OS Type and Version
Do NOT pick Ubuntu (64-bit), even though your machine is 64 bit. Our prebuilt VM is 32-bit Ubuntu.
Pick any name you like
Choose Linux and 32-bit Ubuntu
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Step 3: Set the Memory Size
1024 MB should be sufficient,
but we recommend 2GB.
If your computer has more
RAM, you can increase
accordingly. The more memory
you give to the VM, the better
the performance you will get.
Step 4: Select the Pre-built VM File Provided by Us
Pick this file in the unzipped folder:
SEEDUbuntu-16.04-32bit.vmdk.
Other files in the folder have similar
names (they have a postfix “-s0xx”);
don’t pick any of these files.
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In the above step, you may encounter the following error; otherwise, directly go
to Step 5.
Reason and Solution: This is because you copied the VM files from another VM, which is
already loaded into VirtualBox. These two VMs have the same UUID, which is not allowed by
Virtualbox. Here are several solutions depending on your situations:
•
•
•
If you plan to create multiple VMs using the same image, please use the clone
mechanism (See Appendix A for details).
If the older VM with the same UUID is no longer needed, remove it from VirtualBox will
solve the problem.
If you do want to keep the older VM, you can change the UUID of the new VM. The
fastest way is to directly modify SEEDUbuntu16.04.vmdk, which is a text file.
Search for the ddb.uuid.image entry, and change its value (e.g., change the last
byte from ‘c’ to ‘d’)
Change this entry
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If there is no error (or after you fix the error), your VM will be created successfully.
Successfully created
Step 5: Configure the VM
Click this button
Click the “Advanced” tab
Select “Bidirectional” for both items. The first item allows users
to copy and paste between the VM and the host computer. The
second item allows users to transfer files between the VM and
the host computer using Drag’n Drop.
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Assign more CPUs to this VM if
you prefer. One is sufficient.
Make sure the VBoxVGA setting is
selected.
If your computer screen has a very high
resolution, your VM will look too small
on the screen. You can adjust the scale
factor to make it larger.
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Step 6: Start the VM
Click the “Start” button
Step 7: Stop the VM or Save the VM’s State
When you are done with your VM, you can always shut it down (from inside Ubuntu). A better
alternative is to “freeze” the computer, so everything is saved. When you need it again, you can
“unfreeze” it, and resume from where you left off. This is much faster and convenient than
shutting down and rebooting the VM. To achieve this, you can use the “Save State” option.
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Appendix A: Use “Clone” to create Multiple VMs
Some SEED labs require multiple VMs. The easiest way to create multiple VMs is to create one
first, and then use the “Clone” mechanism to clone it. Before doing the cloning, please ensure
the following:
•
•
•
IMPORTANT: make sure that the VM is fully shutdown (not in a “Saved” state), or there
will be all sorts of problems.
Configure network (see Appendix B); otherwise you have to do it for each VM.
Configure folder sharing (see Appendix D); otherwise you have to do it for each VM.
Right click the VM, and select “Clone…”
Make sure it is “Powered Off”
You can pick a meaningful name
here.
IMPORTANT: we don’t want to
clone the MAC address. Select
this option. If you don’t, both
VMs will have the same MAC
address, and therefore, they will
get the same IP address. That
will cause problems.
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Select the “Full clone” option.
The clone will take a few minutes, depending on the speed of your computer.
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Appendix B: Network Configuration in VirtualBox for SEED Labs
In many of the SEED labs, we need to run multiple guest VMs, and these VMs should be able to (1) reach
out to the Internet, (2) communicate with each other. In Virtualbox, if we use the “NAT” setting (default
setting) for each VM, we can achieve 1, but not 2, because each VM will be placed in its own private
network, not on a common one; they even have the same IP address, which is not a problem because
each VM is the only computer on its own private network. On the other hand, if we use the “Host-only”
setting for each VM, we can achieve 2, but not 1. Using this setting, all the VMs and the host will be put
on a common network, so they can communicate with each other; however, due to the lack of NAT, the
VMs cannot reach out to the outside.
Therefore, in order to achieve all these 2 goals, we have to use a network adapter called “NAT Network”.
The adapter works in a similar way to “local area network” or LAN. It enable VMs communication within
same local network as well as the communication to the internet. All the communication goes through
this single adapter. As show in Figure 1, gateway router transfers the packets among the VMs and transfers
the packets from local network to Internet.
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Configuration Instruction
Step 1: Make sure you are using the most up-to-date VirtualBox. As show in the following figure, click
the “File” on the top left of the VirtualBox main UI. Then choose “Preferences…” option.
Step 2: Click the “Network” tab on left panel. click the “+” button to create a new NAT Networks
(NatNetwork) adaptor (if one does not exist). Double click on the NatNetwork, and look at its
specifications. Set the specifications as the same as what is shown below.
Add a New “NAT Network”
Adapter
“NAT Network” Specifications
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Step 4: Go to VM setting, you need to power off the VM before making the following changes. Enable
Adapter 1(at the same time, disable the other adapters), and choose “NAT Network”.
Select NAT Network
Select the NatNetwork
built in step 2.
Select “Allow VMs” Promiscuous
mode
Troubleshoot 1
Step 5: Now power on the VM, and check the IP address.
Troubleshooting:
•
If VMs cannot ping each other, refresh the MAC Address can resolve the issue. The way to
resolve the issue is shown in figure 4, troubleshoot 1.
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Appendix C: Take Snapshots and Recover from Snapshots
For some labs, you may need to make changes to the operating system. If you make a severe
mistake, your VM may not be able to boot up again, and you will lost everything inside the
failed VM. have done. To avoid such trouble, before doing anything dangerous to the OS, it is
better to take a snapshot of your current VM. You can take as many snapshots as you want.
To restore from a snapshot that you have taken before, you can click the followings (you need
to shut-down the VM first):
Then click this
First click this
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Appendix D: Folder Sharing
Files can be shared between the host computer and the guest operating system in VirtualBox.
The following steps show how to do so.
1. Create the folder to be shared on the host computer. In this tutorial we name the folder
share.
2. Boot the Guest operating system in VirtualBox.
3. Go to the Settings popup window, and select “Shared Folders”
4. Choose the ‘Add’ button.
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5. Choose “Other …”, and select a folder from the popup window.
6. Select Auto Mount and Make Permanent option. Click OK. Click OK again to close the
Settings Dialog.
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7. Open a terminal in the VM. Make a directory and name it host (you can choose any
name you like). Use command “mkdir /home/seed/host”
8. We want files in our mount point (~/host) to be owned by the current user. Also we
want the mounted shared folder to persist after reboot. Hence, we will edit the
/etc/rc.local file (using “sudo gedit /etc/rc.local”) and add the
command below (1000 is the User ID and group ID of the user seed):
sudo mount -t vboxsf -o rw,uid=1000,gid=1000 share /home/seed/host
9. Save the changes and reboot VM. Now anything placed in /home/seed/host inside
the VM should be visible from the share folder on the host machine, and vice versa.