Businesses should pressure software vendors to meet new Microsoft encryption requirements

Strengthening encryption keys may break applications

Businesses should start leaning on vendors now to upgrade applications that use less than 1024-bit encryption before it's too late.

What is currently a voluntary upgrade request from Microsoft is likely to become mandatory within a few months, meaning that apps using weaker encryption keys won't work with a range of Microsoft platforms, says Paul Henry, a security and forensic analyst with Lumension.

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Some vendors may not even make 1024-bit versions of their applications in an effort to avoid having to get federal export permits for them, he says. Many U.S. software vendors shipped products with 256-bit encryption instead, even to domestic customers, so they didn't have to deal with permitting at all.

If vendors don't come up with 1024-bit versions, their apps will stop working with the following Microsoft platforms, Microsoft says: Windows XP, Windows Server 2003, Windows Server 2003 R2, Windows Vista, Windows Server 2008, Windows 7 and Windows Server 2008 R2 operating systems.

The upgrade came on the heels of Microsoft's Windows Update falling prey to Flame malware, which took advantage of its weak keys to sign malware as if it were legitimate Microsoft updates.

So far Microsoft is making the upgrade voluntary, but that is likely to change in order to establish the integrity of Microsoft platforms, says Henry.

Resolving weak keys will become a race against the clock, he says, because it takes 60 to 90 days to get export permits, and that time could lengthen if the government faces a flood of applications from vendors trying to get them.

Henry recommends that corporate users run a testbed where all their applications attempt to connect with the affected Microsoft products to see whether they break. If so they need to find out what the application vendors plan to do about it and take appropriate steps either for an upgrade or for a replacement.

To help alleviate potential problems Microsoft has left a loophole in its upgrade. It will allow applications that are signed before Jan. 1, 2010, to use keys smaller than 1024 bits, so the oldest legacy applications should still work.

Tim Greene covers Microsoft for Network World and writes the Mostly Microsoft blog. Reach him at tgreene@nww.com and follow him on Twitter @Tim_Greene.

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