Security Home > Windows 95, 98 & ME

Unchecked Buffer in Windows Shell Could Lead to Code Execution New

An unchecked buffer in the Windows shell may allow malicious users to exploit a flaw in one of the functions that helps locate incompletely removed applications. The flaw could cause the shell to crash or for code to be executed using the user's privileges.

Issue

The Windows Shell is responsible for providing the basic framework of the Windows user interface experience. It is most familiar to users as the Windows Desktop, but also provides a variety of other functions to help define the user's computing session, including organizing files and folders, and providing the means to start applications.

An unchecked buffer exists in one of the functions that helps to locate incompletely removed applications on the system. A security vulnerability results because it is possible for a malicious user to mount a buffer overrun attack and attempt to exploit this flaw. A successful attack would have the affect of either causing the Windows Shell to crash, or causing code to run in the user's context.

By default, this is not remotely exploitable. However, under very unusual conditions, it could be exploited via a web page. Specifically, if the user has installed, then uninstalled an application with custom URL handlers, and the application's uninstall routine failed to correctly remove the application completely, an attacker could attempt to mount an attack by constructing an HTML web page that seeks to overrun the buffer. Such a web page could be delivered either by posting it on a web site or sending it by email.

Affected Products

  • Microsoft Windows 98, NT 4.0 and 2000

Download

Software patches are available from the following locations:

Further Details

Source: Microsoft Corporation

Reference: Microsoft Corporation

Updated: March 7, 2002

>> Recommended Download - secure your PC from spyware, adware and malware now with Spyware Doctor <<