A row has broken out between Sophos and Microsoft over the alleged patching and management difficulties posed by Windows 7's XP Mode.
The technology allows XP applications to run in a virtualised environment within Windows 7. This offers backward compatibility with applications but comes at the expense of security, according to Richard Jacobs, Sophos chief technology officer.
By creating an easy migration path from XP to Windows 7, bypassing Vista, Microsoft is creating a potential security disaster, Jacobs argues.
XP mode is an independent Windows instance, that shares the odd folder and device with the host Windows 7 installation. What it doesn't share is processes and memory. So it doesn't share security settings, security software, patches etc. It does not inherit any security from the host.
When you use XP mode, you need to patch the copy of XP as well as the host Windows 7. You need to manage settings separately, configure two personal firewalls and install and manage two copies of anti-malware software.
Jacobs said that the problem is made worse because users don't know how to manage virtual machines on a desktop and because of the lack of tools from Microsoft to handle this process. He concludes that XP Mode "risks undoing much of the progress that Microsoft has made on the security front in the last few years".
The argument provoked a robust response from Roger Halbheer, Microsoft's chief security advisor for EMEA. Halbheer describes XP Mode as a temporary mechanism that allows customers to enjoy the better security benefits of the latest Operating Systems while ensuring application compatibility. He describes it as a pragmatic option, and far better than leaving users with only a forklift upgrade option.
Halbheer concludes: "Which risk is higher? Leaving our customers on an eight to ten year old operating system for another few years, or helping them to migrate to a modern one, accepting the drawback with XP Mode?"
Sophos's Jacobs retorts that simply arguing Windows 7 is more secure than XP, but user still need XP compatibility fails to tackle cost of ownership questions raised by he technology.
"The problem is not with the idea of XP mode, but with the lack of management and the lack of clarity about the costs that users will incur," Jacobs said. "I don’t know many IT departments that will be happy to double their workload and costs in the name of security. They’re much more likely to stick with native XP and sacrifice any of the other benefits that Windows 7 might have delivered."
Microsoft developer James O'Neill responded angrily to Jacobs, saying he has got his facts wrong - especially about the lack of management tools. Larger shops should be using Microsoft Enterprise Desktop virtualization (MEDV) software, he said, adding that standalone XP mode uses is only for small shops. "Windows XP Mode is specifically designed to help small businesses move to Windows 7," O'Neill writes.
"XP mode is just standard virtualization software and a pre-configured VM. You can treat the VM as something to be patched via Windows update or WSUS just like a physical PC.
"You install anti-virus software on it like a physical PC. To manage the VM you use the big brother of XPmode." ®