Patch Tuesday: Microsoft plugs IE 'drive-by download' security holes

Microsoft today shipped six bulletins with patches for a total of 12 documented security vulnerabilities in a wide range of widely deployed software products.  Three of the six bulletins are rated "critical," Microsoft's highest severity rating.

The most serious issues affect the company's Internet Explorer browser, including the newest IE 8 on Windows 7.

The Internet Explorer bulletin (MS09-072) covers five documented vulnerabilities that affect all supported versions of the browser (IE 5, 6, 7 and 8).  As previously reported, there is public exploit code available for one of the IE vulnerabilities.

[ SEE: Exploit published for critical IE zero-day flaw ]

Here's why this is considered a high-priority update for all affected Windows users:

The vulnerabilities could allow remote code execution if a user views a specially crafted Web page using Internet Explorer.

An interesting sidebar: All five of the IE vulnerabilities were purchased by a third-party company that buys software flaw information in exchange for the exclusive rights to broker the disclosure process with affected vendors.

This month's Patch Tuesday batch also covers two potential worm holes in Microsoft Windows (Internet Authentication Service). The update (MS09-071) patches critical flaws that could allow remote code execution if messages received by the Internet Authentication Service server are copied incorrectly into memory when handling PEAP authentication attempts.

An attacker who successfully exploited either of these vulnerabilities could take complete control of an affected system. Servers using Internet Authentication Service are only affected when using PEAP with MS-CHAP v2 authentication.

The third critical bulletin (MS09-074) addresses a security flaw in the Microsoft Office Project software. The vulnerability could allow remote code execution if a user opens a specially crafted Project file.

Microsoft also shipped three "important" bulletins to cover the following:

• MS09-069: Vulnerability in Local Security Authority Subsystem Service. This security update resolves a privately reported vulnerability in Microsoft Windows. The vulnerability could allow a denial of service if a remote, authenticated attacker, while communicating through Internet Protocol security (IPsec), sends a specially crafted ISAKMP message to the Local Security Authority Subsystem Service (LSASS) on an affected system.
• MS09-070:  Vulnerabilities in Active Directory Federation Services. Resolves two privately reported vulnerabilities in Microsoft Windows. The more severe of these vulnerabilities could allow remote code execution if an attacker sent a specially crafted HTTP request to an ADFS-enabled Web server. An attacker would need to be an authenticated user in order to exploit either of these vulnerabilities.
• MS09-073: Vulnerability in WordPad and Office Text Converters.  Patches a privately reported vulnerability in Microsoft WordPad and Microsoft Office text converters. The vulnerability could allow remote code execution if a specially crafted Word 97 file is opened in WordPad or Microsoft Office Word. An attacker who successfully exploited this vulnerability could gain the same privileges as the user. Users whose accounts are configured to have fewer privileges on the system could be less impacted than users who operate with administrative privileges.

Microsoft's Security Research & Defense blog offers this nifty chart to help Windows users prioritize the deployment of the other updates appropriately.

Bulletin	Most likely attack vector	Bulletin severity	Max Exploit- ability Index	Likely first 30 days impact	Platform mitigations
MS09-072 (IE)	Attacker hosts a malicious webpage, lures victim to it.	Critical	1	Public exploit code already exists for CVE-2009-3672 affecting IE6 and IE7. We expect to see exploits for other vulnerabilities that affect other IE versions within 30 days.	DEP is enabled by default for IE8 on Windows XP SP3, Windows Vista SP1 and later, Windows Server 2008, and Windows 7.

DEP makes exploiting the public vulnerability significantly more difficult. MS09-073 (Wordpad converter) Attacker sends malicious .doc file (saved in legacy Word version 8 format) to victim who opens it in Wordpad. Critical 2 Less likely to be exploited in first 30 days. Affects only older platforms. MS09-071 (IAS) Attacker on a wireless LAN attacks the Microsoft IAS server providing the 802.1x authentication and encryption via PEAP. Attack would be via the RADIUS protocol. Critical 2 Less likely to be exploited in first 30 days. MS09-074 (Project) Attacker sends a malicious Project file (MPP) to victim who opens it with Project 2003 or earlier. Critical (Critical on Project 2000 only) 2 Less likely to be exploited in first 30 days. Affects only older versions of Project. MS09-070 (ADFS) Attacker able to authenticate to ADFS running in IIS can execute code within the IIS worker process. Important 1 While an exploit may be developed in the first 30 days, the risk to most organizations is low because attack surface is only exposed to authenticated attackers. MS09-069 (LSASS) Attacker on enterprise network authenticates to a server and remotely causes CPU exhaustion. Important 3 Unlikely to be exploited in first 30 days. No chance of code execution