Microsoft will start pushing Service Pack 1 for Windows 7 as well as Windows Server 2008 R2 as of today [1][2]. As usual, the service pack includes a few enhancements and bug fixes in addition to security patches. If you are up to date on patches, the service pack will only add the additional features.

The service pack has been available since February 2011, but so far only as an optional download. The push to making it an automatic download was likely motivated by the upcoming expiration of the "RTM" (Released to Manufacturing) initial version of Windows 7 in April.

The service pack is also available as a stand alone patch image to update existing machines. Or existing Windows 7 users can install the service pack via Windows Update. The size of the download for Windows Update is about 70MB for Windows 7 and 100 MB for Windows Server 2008 R2.

[1] http://technet.microsoft.com/en-us/windows/gg635126.aspx
[2] http://blogs.windows.com/windows/b/bloggingwindows/archive/2013/03/18/windows-7-sp1-to-start-rolling-out-on-windows-update.aspx

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Johannes B. Ullrich, Ph.D.
SANS Technology Institute
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