  Virtual Reality (VR) has gained popularity by providing immersive and
interactive experiences without geographical limitations. It also provides a
sense of personal privacy through physical separation. In this paper, we show
that despite assumptions of enhanced privacy, VR is unable to shield its users
from side-channel attacks that steal private information. Ironically, this
vulnerability arises from VR's greatest strength, its immersive and interactive
nature. We demonstrate this by designing and implementing a new set of
keystroke inference attacks in shared virtual environments, where an attacker
(VR user) can recover the content typed by another VR user by observing their
avatar. While the avatar displays noisy telemetry of the user's hand motion, an
intelligent attacker can use that data to recognize typed keys and reconstruct
typed content, without knowing the keyboard layout or gathering labeled data.
We evaluate the proposed attacks using IRB-approved user studies across
multiple VR scenarios. For 13 out of 15 tested users, our attacks accurately
recognize 86%-98% of typed keys, and the recovered content retains up to 98% of
the meaning of the original typed content. We also discuss potential defenses.
