An obvious security implication is that security problems that have a solution are withheld from the public for up to a month.This policy is adequate when the vulnerability is not widely known or is extremely obscure, but that is not always the case.
Daily updates consist of malware database refreshes for Windows Defender and Microsoft Security Essentials.
Sometimes there is an extraordinary Patch Tuesday, two weeks after the regular Patch Tuesday. Starting with Windows 98, Microsoft included Windows Update that once installed and executed, would check for patches to Windows and its components, which Microsoft would release intermittently.
With the release of Microsoft Update, this system also checks for updates for other Microsoft products, such as Microsoft Office, Visual Studio and SQL Server.
Earlier versions of Windows Update suffered from two problems: This system accumulates security patches over a month, and dispatches them all on the second Tuesday of each month, an event for which system administrators may prepare.
The following day, informally known as "Exploit Wednesday", marks the time when exploits may appear in the wild which take advantage on unpatched machines of the newly announced vulnerabilities.
Tuesday was chosen as the optimal day of the week to distribute software patches.This is done to maximize the amount of time available before the upcoming weekend to correct any issues that might arise with those patches, while leaving Monday free to address other unanticipated issues that might have arisen over the preceding weekend.Patch Tuesday occurs on the second, and sometimes fourth, Tuesday of each month in North America.As far as the integrated Windows Update (WU) function is concerned, Patch Tuesday begins at or UTC ( PST (UTC−8) or PDT (UTC−7).The updates show up in Download Center before they are added to WU, and the KB articles and the Technet bulletin are unlocked later.Microsoft has a pattern of releasing a larger number of updates in even-numbered months, and fewer in odd-numbered months.