CVE-2021-38549

medium

Description

MIRACASE MHUB500 USB splitters through 2021-08-09, in certain specific use cases in which the device supplies power to audio-output equipment, allow remote attackers to recover speech signals from an LED on the device, via a telescope and an electro-optical sensor, aka a "Glowworm" attack. We assume that the USB splitter supplies power to some speakers. The power indicator LED of the USB splitter is connected directly to the power line, as a result, the intensity of the USB splitter's power indicator LED is correlative to its power consumption. The sound played by the connected speakers affects the USB splitter's power consumption and as a result is also correlative to the light intensity of the LED. By analyzing measurements obtained from an electro-optical sensor directed at the power indicator LED of the USB splitter, we can recover the sound played by the connected speakers.

References

https://www.nassiben.com/glowworm-attack

Details

Source: Mitre, NVD

Published: 2021-08-11

Updated: 2026-06-17

Risk Information

CVSS v2

Base Score: 4.3

Vector: CVSS2#AV:N/AC:M/Au:N/C:P/I:N/A:N

Severity: Medium

CVSS v3

Base Score: 5.9

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Severity: Medium

EPSS

EPSS: 0.00292