Keylogger Found in Audio Driver of HP Laptops
The audio driver installed on some HP laptops includes a feature that could best be described as a keylogger, which records all the user’s keystrokes and saves the information to a local file, accessible to anyone or any third-party software or malware that knows where to look.
Swiss cyber-security firm modzero discovered the keylogger on April 28 and made its findings public today.
Keylogger found in preinstalled audio driver
According to researchers, the keylogger feature was discovered in the Conexant HD Audio Driver Package version 126.96.36.199 and earlier.
This is an audio driver that is preinstalled on HP laptops. One of the files of this audio driver is MicTray64.exe (C:\windows\system32\mictray64.exe).
This file is registered to start via a Scheduled Task every time the user logs into his computer. According to modzero researchers, the file “monitors all keystrokes made by the user to capture and react to functions such as microphone mute/unmute keys/hotkeys.”
This behavior, by itself, is not a problem, as many other apps work this way. The problem is that this file writes all keystrokes to a local file at:
Audio driver also exposes keystrokes in real-time via local API
If the file doesn’t exist or a registry key containing this file’s path does not exist or was corrupted, the audio driver will pass all keystrokes to a local API, named the OutputDebugString API.
The danger is that malicious software installed on the computer, or a person with physical access to the computer, can copy the log file and have access to historical keystroke data, from where he can extract passwords, chat logs, visited URLs, source code, or any other sensitive data.
Furthermore, the OutputDebugString API provides a covert channel for malware to record real-time keystrokes without using native Windows functions, usually under the watchful eye of antivirus software.
Keylogger feature confirmed in HP laptops
Modzero researchers said they found the Conexant HD Audio Driver Package preinstalled on 28 HP laptop models. Other hardware that uses this driver may also be affected, but investigators haven’t officially confirmed that the issue affects other manufacturers.
The Conexant HD Audio Driver Package has versions for the following operating systems.
Microsoft Windows 10 32-Bit Microsoft Windows 10 64-Bit Microsoft Windows 10 IOT Enterprise 32-Bit (x86) Microsoft Windows 10 IOT Enterprise 64-Bit (x86) Microsoft Windows 7 Enterprise 32 Edition Microsoft Windows 7 Enterprise 64 Edition Microsoft Windows 7 Home Basic 32 Edition Microsoft Windows 7 Home Basic 64 Edition Microsoft Windows 7 Home Premium 32 Edition Microsoft Windows 7 Home Premium 64 Edition Microsoft Windows 7 Professional 32 Edition Microsoft Windows 7 Professional 64 Edition Microsoft Windows 7 Starter 32 Edition Microsoft Windows 7 Ultimate 32 Edition Microsoft Windows 7 Ultimate 64 Edition Microsoft Windows Embedded Standard 7 32 Microsoft Windows Embedded Standard 7E 32-Bit
HP did not respond to a request for comment from Bleeping Computer in time for this article’s publication.
Modzero researchers say the only way to mitigate the issue is by deleting the MicTray64.exe.