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MacOS Bug Can Expose Passwords in Keychain Access App

Researcher Linus Henze posted a video demonstrating the exploit, which can pilfer login credentials from macOS's Keychain Access app. But he won't help Apple patch it until the company offers a bug bounty program for macOS.

 & Michael Kan Principal Reporter

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An 18-year-old security researcher has discovered a macOS bug that can expose passwords in Apple's Keychain software. But he's refusing to hand over the details to Apple because the company doesn't offer rewards for finding macOS flaws.

The researcher, Linus Henze, posted a video demonstrating the so-called "KeySteal" exploit. It shows him running a rigged application on a MacBook Pro that then extracts all the login credentials stored in the macOS password management system, Keychain Access.

His rigged application only needs a few seconds to run before it can reveal all the stored usernames and passwords in plain text. The vulnerability affects "macOS Mojave and lower," Henze tweeted.

Typically, when a software bug is found the discoverer reports it to the vendor for immediate patching. But not this time. "It's like [Apple doesn't] really care about macOS," Henze told Forbes. "Finding vulnerabilities like this one takes time, and I just think that paying researchers is the right thing to do because we're helping Apple to make their product more secure."

Apple's bug bounty program currently only applies to iOS and is invite-only (and an Arizona teen might soon see a payday for a FaceTime bug he found). All other software flaws and glitches can be reported to Apple's developer-oriented Bug Reporting program.

A separate Mac security researcher, Patrick Wardle, told PCMag he tested Henze's Keychain exploit and it's legit. He agree that Apple should offer a bug bounty program for macOS.

"If [Apple] cared about the security of macOS and their users in my humble opinion it's a no-brainer," Wardle said. "It will it only encourage more security researchers to find these kind of bugs that Apple is clearly missing."

So far, Apple hasn't commented on the macOS bug. But Henze claims the company already emailed him for the details. The good news is that the German security researcher doesn't plan to sell details about the flaw to malicious hackers or cyber arms dealers.

"I definitely know that I won't keep it forever (and I definitely won't sell it!). I'll probably present my findings someday," he tweeted.

To protect yourself from Henze's exploit, it's best to avoid installing applications from untrusted sources. The exploit also doesn't work if the Keychain Access app has been locked.

About Our Expert

Michael Kan

Michael Kan

Principal Reporter

My Experience

I've been a journalist for over 15 years. I got my start as a schools and cities reporter in Kansas City and joined PCMag in 2017, where I cover satellite internet services, cybersecurity, PC hardware, and more. I'm currently based in San Francisco, but previously spent over five years in China, covering the country's technology sector.

Since 2020, I've covered the launch and explosive growth of SpaceX's Starlink satellite internet service, writing 600+ stories on availability and feature launches, but also the regulatory battles over the expansion of satellite constellations, fights with rival providers like AST SpaceMobile and Amazon, and the effort to expand into satellite-based mobile service. I've combed through FCC filings for the latest news and driven to remote corners of California to test Starlink's cellular service.

I also cover cyber threats, from ransomware gangs to the emergence of AI-based malware. In 2024 and 2025, the FTC forced Avast to pay consumers $16.5 million for secretly harvesting and selling their personal information to third-party clients, as revealed in my joint investigation with Motherboard.

I also cover the PC graphics card market. Pandemic-era shortages led me to camp out in front of a Best Buy to get an RTX 3000. I'm now following how the AI-driven memory shortage is impacting the entire consumer electronics market. I'm always eager to learn more, so please jump in the comments with feedback and send me tips.

The Best Tech I've Had:

  • My first video game console: a Nintendo Famicom
  • I loved my Sega Saturn despite PlayStation's popularity.
  • The iPod Video I received as a gift in college
  • Xbox 360 FTW
  • The Galaxy Nexus was the first smartphone I was proud to own.
  • The PC desktop I built in 2013, which still works to this day.

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