Firelinking [Firefox 1.0.2]

From: mikx (mikx_at_MIKX.DE)
Date: 04/18/05

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    Date:         Mon, 18 Apr 2005 12:58:45 +0200


    I really wonder why the Mozilla Foundation decided to release a serious
    security update on a friday night and to disclose the link to my
    proof-of-concept code so quickly. It wasn't intendet from my side to release
    this as a 0day exploit. Please complain to if you
    disagree with their release policy.


    The link tag allows to load a custom image as the icon for a website,
    displayed in the location bar and in the tab title.

    By setting the href attribute of this tag to a javascript url, it is
    possible to call chrome functions and run arbitrary code without user



    The bug is fixed in Firefox 1.0.3. Disable Javascript as a workaround.

    2005-04-12 Vendor informed ( #290036)
    2005-04-12 Vendor confirmed bug
    2005-04-15 Vendor published fix, advisory and link to PoC (mfsa2005-37)
    2005-04-18 This advisory

    __Affected Software

    Tested with Firefox 1.0.2

    __Contact Informations

    Michael Krax <>


    NTBugtraq Editor's Note:
    Most viruses these days use spoofed email addresses. As such, using an Anti-Virus product which automatically notifies the perceived sender of a message it believes is infected may well cause more harm than good. Someone who did not actually send you a virus may receive the notification and scramble their support staff to find an infection which never existed in the first place. Suggest such notifications be disabled by whomever is responsible for your AV, or at least that the idea is considered.

  • Next message: GreyMagic Security: "File Selection May Lead to Command Execution (GM#015-IE)"