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Mozilla Foundation Security Advisory 2006-26

Mail Multiple Information Disclosure

Announced
April 13, 2006
Reporter
CrashFr
Impact
Low
Products
Thunderbird
Fixed in
  • Thunderbird 1.0.8
  • Thunderbird 1.5.0.2

Description

As a privacy measure to prevent senders (primarily spammers) from tracking when e-mail is read Thunderbird does not load remote content referenced from an HTML mail message until a user tells it to do so. This normally includes the content of frames and CSS files, but CrashFr showed it was possible to bypass this restriction through indirection: the direct CSS or iframe src is included in-line, with that including remote content.

Workaround

Switch the "view message body as..." choice to "Simple HTML" or "Plain text". Or for POP mail, after downloading the mail switch to offline mode before reading any of it.

References

https://bugzilla.mozilla.org/show_bug.cgi?id=328917
CVE-2006-1045