Apple Inc. (AAPL) was left red-faced on Tuesday after it emerged that hackers can gain full administrator access to Mac computers running the company’s latest High Sierra operating system without even needing to input a password.

The major security flaw was first disclosed publicly on Twitter by Turkish software developer Lemi Orhan Ergin. In his tweet, Ergin revealed that anyone can access a Mac by clicking “other” on the login screen and entering “root” in the username field.

Once this simple process is complete, rogue users gain authentication as a system administrator. Among other things, that gives them the ability to view and delete all files, reset and change passwords and tinker with Apple ID email addresses.

Apple confirmed that it is working on a software update to fix issue. The company also published step-by-step instructions to help the millions of users at risk protect their machines before the update goes live.

The Verge reports that only High Sierra, Apple’s latest operating system, is affected by the bug. Sierra and other older macOS systems appear to be free of problems.

"We always see malware trying to escalate privileges and get root access," Patrick Wardle, a security researcher at Synack told Wired.com. "This is best, easiest way ever to get root, and Apple has handed it to them on a silver platter." (See also: Why Apple Faces Trouble Ahead.)

High Sierra has been plagued by bugs since it was launched in September. Wardle believes that these flaws could have been avoided or caught earlier if Apple followed its peers by offering a "bug bounty" for information about security vulnerabilities on MacOS. At present, the company only offers a “bug bounty” for iOS.

"A bug bounty program is a no-brainer,” he said. “Maybe this is something that will encourage them to go down that path. It's crazy these kinds of bugs keep blowing up. I don't know if I should laugh or cry." (See also: Alphabet and Apple Fell Out of Favor in Q3: 13F Filings.)

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