Mozilla

Mozilla Foundation Security Advisory 2010-61

UTF-7 XSS by overriding document charset using <object> type attribute

Announced
September 7, 2010
Reporter
David Huang, Collin Jackson
Impact
High
Products
Firefox, SeaMonkey, Thunderbird
Fixed in
  • Firefox 3.5.12
  • Firefox 3.6.9
  • SeaMonkey 2.0.7
  • Thunderbird 3.0.7
  • Thunderbird 3.1.3

Description

Security researchers David Huang and Collin Jackson of Carnegie Mellon University CyLab (Silicon Valley campus) reported that the type attribute of an <object> tag can override the charset of a framed HTML document, even when the document is included across origins. A page could be constructed containing such an <object> tag which sets the charset of the framed document to UTF-7. This could potentially allow an attacker to inject UTF-7 encoded JavaScript into a site, bypassing the site's XSS filters, and then executing the code using the above technique.

References