Same-origin bypass with web workers and XMLHttpRequest

Same-origin bypass with web workers and XMLHttpRequest

Announced

August 6, 2013

Reporter

Federico Lanusse

Impact

High

Products

Firefox, Firefox ESR, SeaMonkey, Thunderbird, Thunderbird ESR

Fixed in

• Firefox 23
• Firefox ESR 17.0.8
• SeaMonkey 2.20
• Thunderbird 17.0.8
• Thunderbird ESR 17.0.8

Description

Mozilla community member Federico Lanusse reported a mechanism where a web worker can violate same-origin policy and bypass cross-origin checks through XMLHttpRequest. This could allow for cross-site scripting (XSS) attacks by web workers.

In general these flaws cannot be exploited through email in the Thunderbird product because scripting is disabled, but are potentially a risk in browser or browser-like contexts.

References

• Cross Domain Policy override using webworkers (CVE-2013-1714)