By Josh Long

IBM employees are free to use their own smartphones while working outside the office, but that doesn’t mean they have unfettered access.

Consider Apple’s iPhone customers.

IBM turns off Apple’s Siri voice-activated personal assistant over concerns that spoken queries could reveal sensitive information, according to an article in the Technology Review, which MIT publishes.

“We’re just extraordinarily conservative,” IBM chief information officer Jeanette Horan told Technology Review. “It’s the nature of our business.”

The disablement of Siri is part of IBM’s overall security strategy at a time when tens of thousands of its employees are reaching the company’s internal networks using smartphones and tablets. IBM also is said to prohibit certain apps like public file-transfer services such as Dropbox and Apple’s iCloud.

IBM, the Technology Review reported, gives BlackBerrys to about 40,000 of it 400,000 employees while 80,000 other workers tap into internal networks using other smartphones and tablets including ones they purchased themselves.