There are security and business case arguments about BYOD. They cast different aspects and there's peta-bytes of valid points out there.
The security argument? Microsoft Windows is still the corporate OS of choice and still therefore the main target for malware writers. As a pre-qualifier - there is no bias towards one Operating System or another here.
Even considering that in most cases, when business asks for something, security considerations are secondary, there is also the point that Windows is by its nature, very hard to make malware-resistant. Plenty of malware problems are not introduced as a result of a lack of user awareness (for example, unknowingly installing malware in the form of faked anti-virus or browser plug-ins), plus plenty of services are required to run with SYSTEM privileges. These factors make Windows platforms hard to defend in a cost-effective, manageable way.
Certainly we have never been able to manage user OS rights/privileges and that isn't going to change any time soon. There is no 3rd party product that can help. Does security actually make an effective argument in cases where users are asking for control over printers and Wifi management? Should such functions be locked anyway? Not necessarily. And once we start talking fine-grained admin rights control we're already down a dark alley - at least security needs to justify to operations as to why they are making their jobs more difficult, the environment more complex and therefore less reliable. And with privilege controls, security also must justify to users (including C-levels) as to why their corporate device is less usable and convenient.
For the aforementioned reasons, the security argument is null and void. I don't see BYOD as a security argument at all, mainly because the place where security is at these days, isn't a place where we can effectively manage user device security - the doesn't change with or without BYOD, and this is likely to be the case for some years to come yet. We lost that battle, and the security strategy has to be planned around the assumption that user subnets are compromised. I would agree that in a theoretical case where user devices are wandering freely, not at all subject to corporate controls, then the scope is there for a greater frequency of malware issues, but regardless, the stance has to be based on an assumption that one or more devices in corporate subnets has been compromised and the malware is designed to connect ingress and egress.
How about other OS flavors, such as Apple OS X for example? With other OS flavors, it is possible to manage privileges and lock them down to a much larger degree than we can with Windows, but as has been mentioned plenty of times now, once another OS goes mainstream and grows in corporate popularity, then it also shows up on the radars of malware writers. Reports of malware designed to exploit vulnerabilities in OS X software started surfacing earlier in 2012, with "The Flashback Trojan" given the widest coverage.
I would venture that at least the possibility exists to use technical controls to lock down Unix-based devices to a much larger degree, as compared with MS Windows variants, but of course the usability experience has to match the needs of business. Basically, regardless of whether our view is utopic or realistic, there will be holes, and quite sizable holes too.
For the business case? Having standard build user workstations and laptops does make life easier for admins, and it allows for manageability and efficiency, but there is a wider picture of course. The business case for BYOD is a harder case to make than we might have at first thought. There are no obvious answers here. One of the more interesting con articles was from CIO Magazine earlier in 2012: BYOD: If You Think You're Saving Money, Think Again and then Cisco objectively report that there are plenty in the pro corner too: Cisco Study: IT Saying Yes To BYOD.
So what does all this bode for the future? The manageability aspect and therefore the business aspect is centered around the IT costs and efficiency analysis. This is more of an operational discussion than an information risk management discussion.
The business case is inconclusive, with plenty in the "say no to BYOD" camp. The security picture is without foundation - we have a security nightmare with user devices, regardless of who owns the things.
Overall the answer naturally lies in management philosophy, if we can call it that. There is what we should do, and what we will do....and of course these are often out by 180 degrees from each other. The lure of BYOD will be strong at the higher levels who usually only have the balance sheet as evidence, along with the sales pitches of vendors. Accountant-driven organisations will love the idea and there will be variable levels of bravery, confidence, and technical backing in the IT rationalization positions. Similar discussions will have taken place with regard to cloud'ing and outsourcing.
The overall conclusion: BYOD will continue to grow in 2013 and probably beyond. Whether that should be the case or not? That's a question for operations to answer, but there will be plenty of operations departments that will not support the idea after having analyzed the costs versus benefits picture.
Cross-posted from Security Macromorphosis