Microsoft is preparing to push a security update to Windows Phone 7 users on May 3.

The software giant has been working on a patch to block several fake SSL certificates that may affect Windows Phone 7 owners. The company originally warned of nine fraudulent digital certificates in late March. Certification authority Comodo issued the certificates in what the company described as a “politically motivated” attack. The certificates have been revoked by Comodo and Microsoft has issued an update for all supported desktop versions of Windows to help address the issue. Microsoft says the certificates may be used to spoof content, perform phishing attacks, or perform man-in-the-middle attacks against all Web browser users including users of Internet Explorer.

Microsoft is currently working on a Windows Phone 7 update to address the issue on its latest range of smartphones. The company confirmed to WinRumors in March that mobile devices, applications and servers accessing websites affected by the nine fraudulent certificates are potentially impacted. “Fraudulent digital certificates are not a Microsoft security vulnerability” explained Microsoft Trustworthy Computing manager Bruce Cowper. “We have been working to develop a mitigation update for Windows Phones,” added Cowper. Microsoft refused to provide a timeline for the update but SlashGear claims the update will be made available on May 3.

It’s not yet clear how Microsoft plans to distribute its third Windows Phone 7 update. It’s likely that the company may use its much talked about over-the-air (OTA) update system. It is thought that the update is small enough that carriers could approve a distribution plan over existing wireless networks. WinRumors has reached out to Microsoft for comment, at the time of writing we have yet to receive a response.