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Vmware workstation 6.5.1 free
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Whichever VM you select, the VM cannot cross the software boundaries set in place. For example, a virus might infect a computer when executed and spread to other files in the OS. So if I'm running VMWare player and execute some malware on my virtual machine's OS, I don't have to worry about my host system being compromised, at all? What if the virtual machine shares the network with the host machine, and shared folders are enabled? Isn't it still possible for a worm to copy itself to the host machine that way?
How secure are virtual machines, really? How much do they protect the host machine from malware and attacks? VMs can definitely cross over. Usually you have them networked, so any malware with a network component i. Regular viruses tend to only operate in usermode, so while they couldn't communicate overtly, they could still set up a covert channel. If you are sharing CPUs, a busy process on one VM can effectively communicate state to another VM that's your prototypical timing covert channel.
Storage covert channel would be a bit harder as the virtual disks tend to have a hard limit on them, so unless you have a system that can over-commit disk space, it should not be an issue.
The most interesting approach to securing VMs is called the Separation Kernel. It's a result of John Rushby's paper which basically states that in order to have VMs isolated in a manner that could be equivalent to physical separation, the computer must export its resources to specific VMs in a way where at no point any resource that can store state is shared between VMs.
This has deep consequences, as it requires the underlying computer architecture to be designed in a way in which this can be carried out in a non-bypassable manner. It is also not very practical for common systems, as to have four VMs, you'd need four harddrives hanging off four disk controllers, four video cards, four USB controllers with four mice, etc.. There have been some white-papers published over the years describing ways that researchers have managed to infest a host OS from a VM.
These are usually seen, rightly so, as security vulnerabilities by the VM vendors and treated as such. Since I first saw those papers, Intel has made some significant processor instruction-set improvements in allowing separation of VM and hypervisor. The few vulnerabilities I see these days are based more in the 'vmtools' portion. This is the software you install to make the guest OS run more efficiently for VMWare this is what allows on the fly cursor capture, and sharing between guest and host without a network.
This is a special software pathway for infection; don't install the tools, don't have the vulnerability. Some malware has show the ability to detect that they're being executed inside a VM and thus change their behavior, much to the aggravation of malware researchers attempting to use VMs as a way to test malware.
I don't know how prevalent it is these days, though. An example of guest-to-host code execution can be found in the Cloudburst exploit. There is a video demonstrating it and a paper from Immunity detailing their success on VMware Workstation 6.
This probably provides little comfort, but I've never heard of this being used in the wild and the exploit is from That book was published in so the author should clean that statement up. A virtual machine is exactly that, a logically separate machine, so it must have the same security layers placed on it as you would a bare-metal system. Using a virtual machine will not stop a vul if it uses normal channels to get to the host machine.
The real beauty in virtualization is the ability to roll back VMs to a state where they were not effected, as well as the ability to better manage available resources. If the proper steps are taken to protect the host machine, virtualization can be extremely secure. I'm only currently aware of host DoS exploits when it comes to hyper-v see this , but I'm sure there are other finds in the horizon.
VMWare has some in it's history too i. Depending on what you're doing, there are some online tools that may be able to take away your need to do the analysis on your own machine.
Here are a few sites to take a look at: - Threatexpert. Other mechanisms, such as spreading across a shared network, are the same as if these were different physical boxes.
I think that author assertion is not completely true. Actually, there are two types of hypervisor in virtualization area. Hypervisor is a piece of computer software, firmware or hardware that creates and runs virtual machine s. Those types are:. Type-1 hypervisor runs directly on the host's hardware to control the hardware and to manage guest operating systems.
For this reason, they are sometimes called bare metal hypervisors whereas Type-2 hypervisor runs on a conventional operating system just as other computer programs do. Stealth VM software installer that allows you to build a Windows 7 clone running in a secure Linux partition. The system is protected from malware, anything you download will be contained w ithin the virtual machine and it is intended for people who must have a specific Windows program with the convenience of being able to restore the operating system as new in just two clicks.
Unlike Type-2 hypervisors, it has a secure inter-VM file transfer system to handle sharing folders' risk. In theory, that organization is more secure than Type-2 virtualization according to developers. This vulnerability may allow an attacker to escape from the confines of an affected virtual machine VM guest and potentially obtain code-execution access to the host.
More details regarding the vulnerability can be found here. Of interest and relevance , the "Pwn2Own" security contest for has as one of its competitions, escaping from a VMWare Workstation virtual machine. Others include escaping browser sandboxes or taking over physical machines. That should give an idea that 1 its at least plausible and 2 if its easy then we have a way to hear it - just check the outcome :.
Exploitable weaknesses in the host OS itself which are not mitigated by running in a VM process if some guest OS calls are erroneously judged "safe" and passed direct by a guest driver to the host OS or device driver for speed, but an exploit exists. Bugs in vendor drivers or vendor code for example, a host driver allows network bridging for the guest OS; perhaps a bug in it might allow calls or code to be made on the host at kernel level.
The scope exists, and given prevalence its surely being examined actively for exploits. Surely vulnerabilities if not exploits will regularly be found and need patching.
Physical isolation will always be more robust than using logical isolation. In physically-isolated systems servers, etc. Of course, the network is another vector that needs to be addressed.
That is also an underlying premise in using Cloud Service Providers CSPs where multi-tenant systems share the same HW, using not only virtualized servers, but also virtual networks and storage. The distinction between Type 1 bare metal and Type 2 hypervisors is an important one. Type 2 hypervisors will not be any more secure than the underlying Host OS.
They also don't typically have the same control over the HW as Type 1 hypervisors do. Hypervisor security capabilities and assurance in their correct operation: Different hypervisors make different claims in terms of VM isolation and control over VM to physical HW resources.
For instance, ESXi claims "VM domain isolation" and it has been independently evaluated for this and other security requirements through the Common Criteria CC process.
If you use a hypervisor that has not been independently validated, you're taking the vendor's word that its does what they claim it does and does it correctly. All complex SW can be misconfigured, exposing vulnerabilities.
All SW may have security bugs implementation vulnerabilities , so it is also important to have a vulnerability management program to quickly identify and patch such. Exploits that are specifically designed to run in vms and target bugs in the underlying host kernel are inevitable. Look for them first in the popular cloud platforms. Sign up to join this community. The best answers are voted up and rise to the top. Stack Overflow for Teams — Start collaborating and sharing organizational knowledge.
Create a free Team Why Teams? Learn more about Teams. How secure are virtual machines really? False sense of security? Ask Question. Asked 11 years, 4 months ago. Modified 1 year, 8 months ago. Viewed k times. Improve this question.
Webster T. Webster 2, 3 3 gold badges 19 19 silver badges 18 18 bronze badges. If I were the editor, I would interject a "hopefully" and "theoretically" in a few choice locations in that quote. As is, it's definitely a false statement. A example of a real life attack from guest os to host os. You should consider installing the absolute minimum of tools, configuring minimum network access and configuring minimum of hardware devices to minimize risk. If you just run a VM in a memory sandbox then you will likely be secure; the only interfaces to attack would be the CPU and memory subsystem of the visor.
You would also have a pretty useless VM. Add a comment. Sorted by: Reset to default. Highest score default Date modified newest first Date created oldest first. Improve this answer. Marcin Marcin 2, 1 1 gold badge 15 15 silver badges 14 14 bronze badges. What would be the benefit of this sort of covert communication for the virus author?
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