MS shores up five critical security holes

Microsoft last night issued five security fixes and two patches to defend against less serious security vulnerabilities, in the debut of its recently announced policy of releasing security patches in a monthly batch.

Software packages and applications affected by the vulnerabilities include Windows Messenger Service and other components of Windows, along with enterprise apps, such as Exchange, so both businesses and consumers are at risk from the flaws.

The Unmagnificent Seven

The critical vulnerabilities include a hole in Windows' Authenticode component that could allow remote code execution (MS03-041); a buffer overflow in the Windows Troubleshooter ActiveX Control component of Win2K (MS03-042) and a buffer overrun in Window’s Messenger Service (MS03-043).

Microsoft also warns of a critical buffer overrun flaw in Windows Help and Support Centre which "could lead to system compromise" (MS03-044).

Meanwhile, enterprises need to be aware of a critical vulnerability in Exchange Server 5.5 and Exchange 2000 Server that could allow arbitrary code execution on servers running unpatched versions of the applications (MS03-046).

There’s also a "moderate" vulnerability in Exchange Server 5.5 Outlook Web Access that could allow cross-site scripting Attacks (MS03-047).

Finally, returning to the consumer space, there's an "important" buffer overrun flaw in the ListBox and in the ComboBox Control of Windows (MS03-045).

Security firm Network Associates warns of the severity of these various flaws: "An attacker can exploit these vulnerabilities by using them to run arbitrary code on a targeted machine. This would allow the attacker to take over control of that machine, use it to launch a further attack, or to deny the use of that machine and its applications to legitimate users."

Security tools firm ISS draws particular attention to the buffer overflow flaw in the Windows Messenger Service, which seems to be the worst of a bad lot. Windows Messenger Service (not to be confused with MSN Messenger) is enabled by default on all Windows NT, Windows 2000 and Windows XP desktops and servers.

An overview of these various patches can be found here and a consumer-orientated bulletin can be found here.

Monthly patches – will it help?

Last week Microsoft CEO Steve Ballmer announced a change in the company's approach to issuing patches designed to make it easier for businesses to organise and manage the application of security fixes. Instead of issuing patches on a weekly or ad-hoc basis, Microsoft is releasing patches on a monthly basis. The move is part of Microsoft's ongoing Trustworthy Computing initiative.

However, Alan McGibbon, CEO of newly launched UK security firm NetSecure, which specialises in patch management, warns that Microsoft's changed approach is not without its drawbacks.

"Monthly security alerts inherently makes things less secure because any new vulnerability will reside on a system for longer. It takes the freedom of choice away from people about whether to apply patches," he told The Register.

McGibbon, while welcoming the spotlight Microsoft has shone on the patch management issue, said that he preferred Microsoft's previous approach of "near time alerts". He added that whatever approach Microsoft takes the "onus is on end users" to apply patches by establishing an effective patch management regime, using either internal staff or a third party.

"Patch management becoming an increasing problem. It's a resource issue and a skills issue. Part of the problem is that the kind of information Microsoft, or other vendors, provides in security alerts do not help companies to determine business risk.

"With over 4000 vulnerabilities reported in 2002 and nearly 2000 vulnerabilities reported in the first six months of this year, companies that don't practice good patch management are at significant risk from hack attacks and other security breaches," he added. ®