The lull should be welcomed following several months last year when Microsoft's security bulletins set records.
One reason for the light patch cycle is that fixes for some known problems are missing. Kaspersky security researcher Roel Schouwenberg notes that two well-known vulnerabilities were not addressed this month, an XSS vulnerability (CVE-2011-0096) and a Windows Browser protocol vulnerability.
Andrew Storms, director of security for nCircle, expects there will be more patches next month as a result of the CanSecWest Pwn2Own hacking competition, which starts on Wednesday.
Microsoft's March patches address flaws in Microsoft Windows and Office. Only one of three bulletins is rated critical, MS11-015.
It resolves a vulnerability in DirectShow and a vulnerability in Windows Media Player and Windows Media Center.
Symantec says that the more serious of the two flaws could allow remote code execution if a user can be convinced to open a malicious Microsoft Digital Video Recording (.DVR-MS) file.
"To exploit this issue a user has to open a malicious file, so some social engineering would need to be employed," said Symantec security researcher Joshua Talbot in an e-mailed statement. "However, because DVR-MS files are media files used by common Windows applications, it's not hard to imagine a scenario where an attacker spreads a malicious file purporting to be a video clip related to some popular current event."
Qualys CTO Wolfgang Kandek suggests that if IT administrators find themselves with more time than usual this month due to the light patch cycle, they may wish to consider identifying whether there's any further need for Internet Explorer 6. Microsoft is now urging companies to upgrade from IE 6. Kandek says that security scans conducted by his company show 26% of machines still have IE6 installed, considerably higher than the 12% reported by Microsoft.