Patch Tuesday Analysis for March 2006

This Month's Security Updates from Microsoft

Microsoft released 2 security bulletins today, one that affects Office and another that impacts certain Windows versions that have weak permissions defined for certain services. For full details see below.

MS06-012 - Permissive Windows Services DACLs Could Allow Elevation of Privilege (914798)

On Windows XP pre-SP2 and Windows Server 2003 pre-SP2 the default permissions for a number of system services allow a non-administrative user write access to certain properties that would allow the attacker to elevate their privileges to administrator level apparently by pointing the service to a specially written executable that would exploit the administrator level authority under which the service runs to do the attacker's bidding. As an elevation of privilege risk that requires a valid logon I don't regard this as critical to load except on sensitive servers where you've already made a full hardening effort or on workstations where you are committed to preventing end-users from gaining administrator access to their own workstation. Terminal Services servers delivering applications to end-users should receive this patch to prevent end-users from gaining administrator access to the server. At the same time, this patch presents low risk to stability since it makes no updates to executable files, it simply strengthens the ACL on ssdpsrv, netbt, upnphost, scardsvr, dhcp and dnscache services. Unless you have an automated process running as an unprivileged account updating these services the patch probably won't be noticeable.
This patch again demonstrates the dividend gained by staying up-to-date with the latest service pack since up-to-date Windows 2000, 2003 and XP systems are immune.

MS06-011 - Vulnerabilities in Microsoft Office Could Allow Remote Code Execution (905413)

This security update patches a number of vulnerabilities associated with various Office and MS Works programs and you should be concerned if you have systems with Office 2000, XP, 2003 or MS Works Suite 2000-2006, Excel Viewer
2003 or even Excel for Mac. These vulnerabilities allow an attacker to run arbitrary code on remote systems where he is successful in getting the user to open a specially formed Office document through email attachment, download from webpage and similar vectors. Since information on how to exploit some of the vulnerabilities in this patch are already public, I recommend loading this patch on all vulnerable systems as soon as possible after basic testing in your environment.

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