Exploit matérialisé

CVE-2019-5789

HIGH

1 exploit(s) public(s) pour cette CVE, 1 matérialisé(s) avec leur code.

À des fins de recherche défensive uniquement. Ne testez que sur des systèmes que vous possédez ou pour lesquels vous détenez une autorisation écrite. L'accès non autorisé est illégal.

ExploitDB dos multiple Vérifié

Source

Google Chrome < M73 - MidiManagerWin Use-After-Free

Par Google Security Research

Comment tester cet exploit

Déni de service : envoie une entrée malformée pour crasher le service. À tester en VM isolée, l'effet est destructif.

Code txt

MidiManagerWin uses a similar instance_id mechanism to the TaskService implementation to ensure that delayed tasks are only executed if the MidiManager instance that they were scheduled on is still alive.

However, this instance_id is an int, and there is no check that it hasn't overflowed, unlike in the linux and mac implementations (MidiManagerAlsa), see https://cs.chromium.org/chromium/src/media/midi/midi_manager_alsa.cc?rcl=282aae73b9d2c1cbf12d3c39a8d3d2612e4b1876&l=175

This means that if (for example) a delayed sendData on a stale MidiManagerWin instance is queued up, and then the instance id is wrapped, this will trigger a use-after-free when that task triggers.

This bug would be theoretically reachable directly from javascript, but I think that since it's not possible to directly tear down a midi session using the WebMIDI api that this would require too much time to be feasible (as it would require creating a new frame for every increment). However, it can be triggered in a reasonable amount of time from a compromised renderer making direct Mojo calls.

The timing required for the resulting code is quite sensitive to changes in the order of Mojo messages being received; my original approach needed 6 months, but I have the time needed to cause the overflow down to ~4 days from a compromised renderer using the MojoJS javascript bindings.

I've attached a PoC (using the MojoJS bindings) that demonstrates the issue in a more convenient amount of time for testing if you patch the variable `static int id` in IssueNextInstanceId to a `static short`. Runtime will also be shorter if you run the PoC directly after booting; it also has to synchronise clocks with the system clock, and I haven't put any work into making that quick.


Proof of Concept:
https://gitlab.com/exploit-database/exploitdb-bin-sploits/-/raw/main/bin-sploits/46570.zip