Mozilla Foundation Security Advisory 2005-33

Javascript "lambda" replace exposes memory contents

Announced
April 15, 2005
Reporter
Azafran/Vladimir V. Perepelitsa
Impact
Moderate
Products
Firefox, Mozilla Suite
Fixed in
  • Firefox 1.0.3
  • Mozilla Suite 1.7.7

Description

A bug in javascript's regular expression string replacement when using an anonymous function as the replacement argument allows a malicious script to capture blocks of memory allocated to the browser. A web site could capture data and transmit it to a server without user interaction or knowledge.

The attacker cannot control what will be captured, but the data returned sometimes contains bits of websites the user has recently visited and their addresses. The data could be sifted to find the occasional valuable bits of information.

Workaround

Disable Javascript.

References