[ISN] Microsoft issues patch for serious security hole

From: InfoSec News (isnat_private)
Date: Thu Nov 21 2002 - 07:17:00 PST

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    By Paul Roberts
    IDG News Service
    Microsoft issued a software patch Wednesday for what it described as a
    "critical" new security vulnerability affecting most versions of its
    Windows operating systems and certain versions of the Internet
    Explorer (IE) Web browser.
    The security flaw affects the Microsoft Data Access Components (MDAC),
    a collection of components that provide database access for Windows
    platforms, according to a statement from Foundstone, a software
    vulnerability management company in Mission Viejo, Calif., that
    discovered the flaw.
    The vulnerability involves what's known as an "unchecked buffer" in
    the Remote Data Services (RDS) component of MDAC. The faulty code is
    in a function called the RDS Data Stub which is used to pull
    information from incoming HTTP requests and create RDS commands,
    according to Microsoft.
    An attacker could exploit the security weakness by sending an
    improperly formatted HTTP (Hypertext Transfer Protocol) request to the
    Data Stub that contained a surplus of data, causing the buffer to
    overflow and the attacker's data to be placed and run on the affected
    The vulnerability affects certain versions of Windows NT, Windows 2000
    and Windows Me, Microsoft said, and potentially other versions of its
    operating system. It said Windows XP users are not affected and need
    take no action.
    The vulnerability received a severity rating of "critical" from
    Microsoft, the highest possible rating under the company's new
    vulnerability rating system, which was announced Tuesday. Microsoft
    defines critical vulnerabilities as those "whose exploitation could
    allow the propagation of an Internet worm such as Code Red or Nimda
    without user action."
    The security hole is particularly menacing because of the large number
    of systems that are vulnerable to it and because of the ease with
    which existing worms such as Code Red or Nimda could be modified to
    take advantage of the newly disclosed flaw, said Stuart McClure,
    Foundstone's president and CTO.
    "What makes it really quite dangerous is that it can be easily added
    to a worm," McClure said.
    "It's very much in line with Code Red and Nimda because of the attack
    vectors and the ways that it attacks. But with this vulnerability both
    the server and client component can be attacked, as opposed to Code
    Red and Nimda, which basically exploited server-based vulnerabilities
    and didn't take advantage of a browser based vulnerability like this,"  
    he said.
    Foundstone discovered the vulnerability in August and disclosed the
    information to Microsoft at that time, McClure said.
    The vulnerability affects MDAC versions 2.1, 2.5 and 2.6, according to
    Microsoft. MDAC is installed and implemented by default in Windows
    2000, and within the Windows NT 4.0 option pack.
    Machines running Internet Explorer versions 5.01, 5.5 and 6.0 are also
    affected by the new vulnerability, Microsoft said.
    Earlier versions of either MDAC or Internet Explorer that are no
    longer supported may also be vulnerable, the software maker said.
    Customers who are potentially affected are advised to review the
    appropriate security bulletin, MS02-065, on Microsoft's Web site. The
    bulletin is here.
    They should then download and install the software patch issued by
    Microsoft, which is here.
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