Loophole: Timing Attacks on Shared Event Loops in Chrome Pepe Vila - - PowerPoint PPT Presentation

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Loophole: Timing Attacks on Shared Event Loops in Chrome Pepe Vila - - PowerPoint PPT Presentation

Apr 21, 2023 420 likes •1.06k views

Loophole: Timing Attacks on Shared Event Loops in Chrome Pepe Vila and Boris Kpf vwzq.net @cgvwzq github.com/cgvwzq DISCLAIMER: CRYPTACUS DISCLAIMER: CRYPTACUS DISCLAIMER: CRYPTACUS (its funny because its very ubiquitous)

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Loophole: Timing Attacks on Shared Event Loops in Chrome

Pepe Vila and Boris Köpf

vwzq.net @cgvwzq github.com/cgvwzq

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SLIDE 2

DISCLAIMER:

CRYPTACUS

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DISCLAIMER:

CRYPTACUS

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SLIDE 4

DISCLAIMER:

CRYPTACUS

(it’s funny because it’s very ubiquitous…)

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SLIDE 5

DISCLAIMER:

CRYPTACUS

(it’s funny because it’s very ubiquitous…)

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Event-driven programming

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Source: http://berb.github.io/diploma-thesis/original/042_serverarch.html

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SLIDE 8

FIFO queue Dispatcher

time

Shared Event Loop

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FIFO queue Dispatcher

time

e0

Shared Event Loop

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FIFO queue Dispatcher

time

e0

Shared Event Loop

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FIFO queue Dispatcher

time

e1 e0

Shared Event Loop

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FIFO queue Dispatcher

time

e1 e0

Shared Event Loop

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FIFO queue Dispatcher

time

e0 e1

Shared Event Loop

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FIFO queue Dispatcher

time

e0 e1 e2

Shared Event Loop

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FIFO queue Dispatcher

time

e0 e1 e2

Shared Event Loop

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FIFO queue Dispatcher

time

e0 e2 e1

Shared Event Loop

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FIFO queue Dispatcher

time

e0 e1 e2

Shared Event Loop

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FIFO queue Dispatcher

time

e0 e1 e2

Shared Event Loop

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FIFO queue Dispatcher

time

e0 e1 e2 e3

Shared Event Loop

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FIFO queue Dispatcher

time

e0 e1 e2 e3

Shared Event Loop

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FIFO queue Dispatcher

time

e0 e1 e3 e2

Shared Event Loop

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FIFO queue Dispatcher

time

e0 e1 e2 e3

Shared Event Loop

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FIFO queue Dispatcher

time

e0 e1 e2 e3

Shared Event Loop

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FIFO queue Dispatcher

time

e0 e1 e2 e3 e4

Shared Event Loop

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FIFO queue Dispatcher

time

e0 e1 e2 e4 e3

Shared Event Loop

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FIFO queue Dispatcher

time

e0 e1 e2 e3 e4

Shared Event Loop

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FIFO queue Dispatcher

time

e0 e1 e2 e3 e4

Shared Event Loop

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FIFO queue Dispatcher

time

d0 d1 d2 d3

e0 e1 e2 e3 e4

Shared Event Loop

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FIFO queue Dispatcher

time

Event-delay trace

d0 d1 d2 d3

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Shared Event Loop

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We exploit 2 different shared Event Loops in Chrome:

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We exploit 2 different shared Event Loops in Chrome:

I/O’s of the Host Process Main thread’s of Renderers

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We exploit 2 different shared Event Loops in Chrome:

I/O’s of the Host Process Main thread’s of Renderers

And implement 3 different attacks:

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Page Identification

And implement 3 different attacks: We exploit 2 different shared Event Loops in Chrome:

I/O’s of the Host Process Main thread’s of Renderers

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And implement 3 different attacks:

19780.000 19785.000 19790.000 19795.000 19800.000 0.02 0.04 0.06 0.10 0.20 0.40 1.00 2.00 4.00 10.00

Inter-keystroke Timing Page Identification

We exploit 2 different shared Event Loops in Chrome:

I/O’s of the Host Process Main thread’s of Renderers

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We exploit 2 different shared Event Loops in Chrome:

I/O’s of the Host Process Main thread’s of Renderers

And implement 3 different attacks:

Page Identification Covert Channel

19780.000 19785.000 19790.000 19795.000 19800.000 0.02 0.04 0.06 0.10 0.20 0.40 1.00 2.00 4.00 10.00

Inter-keystroke Timing

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SYSTEM/INTERNET

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HOST PROCESS SYSTEM/INTERNET

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HOST PROCESS SYSTEM/INTERNET

  • NETWORK REQUESTS
  • IPC COMMUNICATION
  • DISPATCHES USER

ACTIONS

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HOST PROCESS SYSTEM/INTERNET

RENDERER 1 RENDERER 2 tab1 | trusted.com tab 2 | SHARED BETWEEN ALL RENDERERS

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HOST PROCESS SYSTEM/INTERNET

RENDERER 1 RENDERER 2 tab1 | trusted.com tab 2 |

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HOST PROCESS SYSTEM/INTERNET

RENDERER 1 RENDERER 2 tab1 | trusted.com tab 2 | evil.com

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<script>
 function loop () { save(performance.now()); fetch(new Request("http://0/")) .catch(loop); } loop(); </script>

Timing resolution of ~500 μs

Spying on the Host

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Timing resolution of ~500 μs With SharedWorkers we obtain <100 μs

<script>
 function loop () { save(performance.now()); fetch(new Request("http://0/")) .catch(loop); } loop(); </script>

Spying on the Host

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HOST PROCESS SYSTEM/INTERNET

RENDERER 1 tab1 | trusted.com

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HOST PROCESS SYSTEM/INTERNET

RENDERER 1

  • JAVASCRIPT EXECUTION
  • RESOURCE PARSING
  • LAYOUT & RENDERING

tab1 | trusted.com

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HOST PROCESS SYSTEM/INTERNET

RENDERER 1 iframe |

SHARED BETWEEN IFRAMES, POPUPS, MAX #RENDERER EXCEEDED…

tab1 | trusted.com

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HOST PROCESS SYSTEM/INTERNET

RENDERER 1 iframe | evil.co tab1 | trusted.com

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<script>
 function loop() { save(performance.now()); self.postMessage(0, "*"); } self.onmessage = loop; loop(); </script>

Timing resolution of <25 μs

Spying on the Renderer

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LoopScan Tool

https://github.com/cgvwzq/loopscan

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Web Page Identification & Inter-keystroke Timing

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Web Page Identification

Monitor the EventLoop while page loading

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Dynamic Time Warping

DTW is resistant to delays in the occurrence of events

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Dynamic Time Warping

DTW is resistant to delays in the occurrence of events

2-4 seconds of measuring

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Dynamic Time Warping

DTW is resistant to delays in the occurrence of events

2-4 seconds of measuring One trace for training

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Web Page Identification

500 pages x 30 traces x 3 machines x 2 event loops

Renderer’s main thread: Host’s I/O thread:

75%

23%

(Linux desktop) (Macbook Pro)

(recognition rates below 5% across machines) R-library and datasets:
 https://github.com/cgvwzq/rlang-loophole

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Inter-keystroke Timing

19780.000 19785.000 19790.000 19795.000 19800.000 19805.000 0.02 0.04 0.06 0.10 0.20 0.40 1.00 2.00 4.00 10.00

We obtain the password length and
 time between consecutive pressed keys

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Inter-keystroke Timing

10.000 passwords 90% accuracy precision: σ = 6.1 ms

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Inter-keystroke Timing

More precision than network based attacks. Less noise than in micro-architectural attacks. No privileges. No training. 10.000 passwords 90% accuracy precision: σ = 6.1 ms

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Countermeasures

  • Reduce clock resolution
  • Site Isolation Project
  • CPU throttling
  • Rate limiting
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Countermeasures

  • Reduce clock resolution
  • Site Isolation Project
  • CPU throttling
  • Rate limiting
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Conclusions

  • Shared event loops in Chrome are vulnerable to

timing side-channels

  • We systematically study how this channel can be

used for different attacks

  • Fundamental design issues that need to be

addressed

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Thank you! :)

Questions?