It’s Patch Tuesday once again and for this month, Microsoft released four important security bulletins to address nine vulnerabilities.

Microsoft Security Bulletin MS08-037
Vulnerabilities in DNS Could Allow Spoofing (953230)

Microsoft Security Bulletin MS08-038
Vulnerability in Windows Explorer Could Allow Remote Code Execution (950582)

Microsoft Security Bulletin MS08-039
Vulnerabilities in Outlook Web Access for Exchange Server Could Allow Elevation of Privilege (953747)

Microsoft Security Bulletin MS08-040
Vulnerabilities in Microsoft SQL Server Could Allow Elevation of Privilege (941203)

Along with the following security updates is this month’s update for the Microsoft Malicious Software Removal Tool (MSRT). The said update targets malware identified by Microsoft as Win32/Horst. Horst is a combined kit seen in peer-to-peer (P2P) networks. Trend Micro detects the said malware as the following:

• BKDR_MEDBOT.CJ
• BKDR_MEDBOT.CK
• BKDR_MEDBOT.DB
• MAL_HORST
• TROJ_MEDBOT.AI
• WORM_MEDBOT.AI

Both MEDBOT and HORST families are known partners in crime which turns computers into spam-churning machines. A more detailed report on this malicious partnership can be found here.

MEDBOT has infected more than 700 systems so far this year, a big decline compared to last year, where it infected more than 5,000 computers in the year’s first half alone. HORST on the other hand remains hot, infecting almost 120,000 systems in 2007, and managing to affect about 43,000 in the last 6 months.

These security updates stirred some attention due to reported conflict issues in systems installed with ZoneAlarm products. Users who installed the MS updates experienced Internet connection loss. In line with this, ZoneAlarm also issued an update for users to resolve the connection loss. The solution, as well as identified workarounds, can be found here.

Users are strongly advised to update their PCs with the latest patches from Microsoft as soon as possible.