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Chris Fleck

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Citrix Virtualization: Article

Limos and Laptops: Why and How to Provide Safe Access from Untrusted PCs

Hidden costs of IT policy can help justify Desktop Virtualization

The perceived security risk of granting access from untrusted PCs such as airport kiosks,hotels or even home computers has outweighed the benefits of broad remote access for many enterprises. As a result, those companies typically have IT security policies that dictate only a corporate laptop with the IT supported corporate image plus a VPN can gain access from outside the corporate network. While this policy does provide a certain level of security, it also contributes to many hidden costs both tangible and intangible.

Most IT shops are well aware of the visible costs associated with this policy as it relates to purchasing and maintaining laptops, plus the burden of supporting IPsec VPNs. While laptops are easily justified for road warriors and remote workers, the business case for “day extenders” is less clear, especially when considering the TCO of a laptop being two times that of a typical office PC. In addition to the direct costs of purchasing laptops, there can be significant indirect costs due to security, increased theft, breakage and associated lost productivity during repair and replacement. These recognized costs contribute to additional corporate policies that limit laptops to certain job levels and responsibilities.

But what about all those “potential day extenders” and others that don’t fit the job description with a real mobile requirement for a corporate laptop?  What is the cost of not providing remote access to these employees?  Certainly there is the opportunity cost of lost productivity, when compared to office employees that do have remote access who often find themselves spending an hour or more daily catching up on email or preparing for the next days deadline. Try calculating the value of these potentially productive hours times the number of employees without remote access to start to quantify the impact. How about the human resource impact of limiting employee remote access? Consider the job satisfaction impact of being continuously stuck at the office working overtime when all that is really required is access to email and a few critical applications. Or, how may sick days are logged by employees when it’s really a sick kid at home that can’t be left alone? Just as bad, coming to work while sick and spreading it to others. Most managers would rather have their employee at home online and productive as well as a less stressed employee without conflicting family priorities. What about business continuity?  When these employees stay at home due to snow days or hurricane warnings, again there is additional quantifiable business impact and unnecessary lost productivity.

Here is another example of a hidden cost that is real but completely overlooked because it does not come from the IT budget. In New York City it’s common corporate policy for professionals who work past 8:00 PM to be provided a car service or limo ride home. Look around Manhattan streets any workday evening, and it’s obvious this is a common occurrence. Look a bit further at what is keeping these “potential day extender” employees at work, and the chances are many of them are stuck at the office working on a few mission critical applications on an office PC and possibly because they are working on sensitive data that must stay inside the enterprise. If these same employees had the option of completing their day on their home PC on their own schedule, chances are they would gladly pass up the late night limo rides. This may be a bit of an extreme example, but further investigation into the full impact of IT policy at other enterprises may turn up analogous costly scenarios. So, recognizing the potential benefits of allowing access from otherwise untrusted PC’s, let’s explore the downside. The basic risks of providing remote access from any PC - trusted or not - includes the potential loss of sensitive corporate data, and additionally the damage that could be done by allowing a hacker or malware inside the corporate network.

Loss of sensitive data through remote access can happen in numerous ways; it could be careless or inadvertent employee usage of web based corporate email on public systems which may leave traces of confidential information or even full documents from reading or editing email attachments. Keystroke loggers can also collect ID and passwords that allow a hacker to later gain unauthorized access to corporate networks wreaking havoc or silently stealing critical information. Limiting access from only trusted corporate laptops with a managed image can reduce the some of these risks, however this policy also can introduce new risks including stolen laptops or employees using un-trusted networks to gain access. In addition, for employees who don’t have a corporate laptop or don’t want to carry one home everyday, the practice of emailing a document to a insecure personal public email account can be commonplace, yet very difficult to prevent.

Keeping out malware and hackers is the other significant driver for restricting access from untrusted PC’s. It is easy to recognize the risk of providing full network access via an IPsec VPN to a home PC that can be infected with unknown worms and virus which could traverse the network connection directly to corporate datacenter servers. For those with teenagers at home using the family home PC this risk is certainly understandable.  Additional risks are also possible by utilizing IPsec VPN’s that require multiple ports to be open to the datacenter resulting in management overhead and risk of error. The Corporate laptop can reduce some of these risks by managing the installed image and assuring current spyware and anti-virus scans are routinely run. The IPsec VPN risk and overhead can also be reduced by implementing SSL-VPN’s that can limit the open ports and providing a single managed proxy for all traffic entering the datacenter.

So is it possible to provide access from an un-trusted PC that is as safe or safer than a corporate laptop with a VPN? It is very important to consider the reference point, not the ultimate secure environment but rather a standard corporate laptop with an IPsec VPN. As discussed above this reference environment does have inherent risks, starting with distributed sensitive data that could be exposed if a laptop is stolen or even simply left unattended. Windows password protection can now be easily broken with hacker boot CD's that allow the logon password to be reset and gain full access to the laptop contents. Some hacker tools even provide the ability to revert to the original password so the breach is undetected. Aside from loss of corporate data, corporate laptops are also susceptible to providing a hacker full network access. Silent installs of keystroke loggers from attachments or simple web site viewing. This risk is reduced depending on the effectiveness of the corporate spyware and antu-virus scans and policies; however there are also trade-offs regarding user impact, policy enforcement, and scanning frequency.

Based on this corporate laptop and IPsec VPN reference point, many enterprises are considering the alternatives and the benefits of a broader access strategy. Many have  turned to SSL-VPN's initially due to the support advantages over IPsec VPN's and more recently in combination with End-Point Security enforcement software. Many of these solutions are being implemented on both corporate laptops as well as home PC's. The benefit is enforcement of corporate policies for untrusted PC's: if the endpoint security test passes, then access is granted. A common limitation of many vendors' offerings is the remediation steps required when the test fails. Does your company really want to take over support for home PC's? A few vendors including Citrix do offer policy-based controls that can provide useful and sufficient access to certain applications and functions.

Exploring deeper the scenario of providing safe access from a untrusted PC, some enterprises may not accept the practice to allowing sensitive corporate data on anything but a corporate controlled asset. Providing network access even under controlled environments can still pose an increased risk.  Security tokens from companies like RSA or Gemalto provide One Time Passwords ( OTP ) that can foil keystroke loggers however employees need to have the token to gain access. Recently "Soft" Tokens or Cell phone texting OTP's from companies like SMS Passcode can provide secure authentication without an additional device. In addition to "Two Factor " authentication the safest implementation is to restrict access to the most secure "eyes only" access policy. For example, Citrix XenDesktop can easily be configured to enable access to a virtual desktop with all the required applications to work on, yet only SSL encrypted pixels and keystrokes are passed over the internet. Additional functions like local printing, local file access and Cut & Paste can be easily disabled by the IT administrator, yet the user is able to effectively get their "extended day" work complete. This " eyes only " configuration also minimizes potential threats to the datacenter by transmitting only the ICA protocol which is benign to transmitting worms, and as a result is unattractive to hacker exploits. Other solutions also exist based on VNC and RDP that can provide server based access with limited or no data getting to the client. Many companies are now considering Desktop Virtualization solutions such as providing a locked-down corporate Virtual Image that can be isolated and run directly on an un-trusted PC or hosted centrally (VDI) with a secure SSL-VPN connection.

So as evidenced above, much can be done to provide safe access from otherwise untrusted PCs. In fact, when compared to the benchmark standard, the VPN connected corporate laptop it is possible to configure a solution that is arguably as safe as or even safer than the typical corporate laptop scenario. Many leading enterprises are now considering the practice of providing employees an allowance to buy whatever PC or laptop they wish for remote access instead of having to deal with a multitude of unique requests. This is often referred to as BYOC " Bring Your Own Computer ". In an uncontrolled environment this could turn into a support and security nightmare. However, when deployed in conjunction with some of the solutions mentioned above, the scenario can turn out to be a win-win for employees and IT. So the time may be right to reconsider the de-facto remote access policy at your company, and consider a Desktop Virtualization strategy that includes all the costs. Chances are you can find more productive ways to spend money than late night limo rides.

More Stories By Chris Fleck

Chris Fleck is Vice President of Emerging Solutions at Citrix Systems. Chris started his career at IBM working across multiple engineering and product organizations leading to Business Unit Exec of the IBM Industrial Computer Group. As a pioneer of new technologies, Chris founded an IBM spin-off to commercialize the initial Server Blade products as CEO of OmniCluster Technologies. At Citrix Chris is responsible for Emerging Solutions and is involved with or leading strategic initiatives at the company. You can follow him on Twitter and his blog at