Three of the eight patches that Microsoft released earned its most dire “critical” label, meaning the vulnerabilities fixed in them can be exploited by malware or miscreants remotely without any help from Windows users. Among the critical patches is an update for Internet Explorer (MS13-088) that mends at least two holes in the default Windows browser (including IE 11). MS13-089 is a critical file handling flaw present in virtually every supported version of Windows.
The final critical patch – MS13-090 — fixes essentially another IE flaw (ActiveX) that showed up in targeted attacks late last week. Microsoft says attackers used a second, “information disclosure” vulnerability in tandem with the ActiveX flaw, but that the company is still investigating that one. It noted that its Enhanced Mitigation Experience Toolkit (EMET) tool successfully blocked the ActiveX exploit.