If you’re still clinging to the myth that just because you’re using an Apple Mac, your data is safe from hackers… Well, stop it. Fact is, Apple’s Mac OS X is no better than any other operating system – no matter if you’re running Windows, Linux or anything else, there are dozens of security weaknesses and that’s just something you’re gonna have to accept.

Take the latest new bug – actually an old, unaddressed bug that Apple’s known about for five months already – which has suddenly become a whole lot easier to exploit, putting the data of millions of Mac users at risk. The existing vulnerability already meant that hackers were able to get past Apple’s standard security measures by tweaking specific user timestamp and clock settings, allowing them unlimited access to the machine’s files.

Now though, the developers of testing software Metasploit have come up with a brand new module that makes the bug even easier to exploit, renewing interest in the problem, reports ArsTechnica.

The flaw is due to a Unix program called sudo that grants users various levels of operational access to your Mac machine dependent on their privilege level. Those with full privileges are allowed access to the files of other users on a specific machine, though this level of control is protected by a password.

Only now you don’t need to input a password to gain that access. Instead, Metasploit’s team have identified a flaw that involves setting the clock on the machine back to January 1, 1970, also known as the “Unix epoch,” which is ‘zero hour’ for Unix time and the basis for all of its calculations. Simply by resetting the clock on any Mac, together with the sudo user timestamp, anyone can bypass privilege limitations and restrictions on the machine.

H.D. Moore, founder of Metasploit, warned that this was a serious vulnerability:

“The bug is significant because it allows any user-level compromise to become root, which in turn exposes things like clear-text passwords from Keychain and makes it possible for the intruder to install a permanent rootkit.”

The problem with Mac computers is that OS X versions 10.7 to 10.8.4 do not require a password for anyone to change the timestamp and clock settings, unlike with most Linux operating systems which are affected by the same problem yet password protect their clocks.

Nevertheless, there are limitations to the vulnerability. In order to get it to work, whoever’s using the Mac needs to be logged in with administrator privelages and they need to have run the sudo program at least once previously, whether they’re logged in physically or using the machine by remote.

To date, Apple has yet to issue a fix for this vulnerability:

“I believe Apple should take this more seriously,” said Moore. “But am not surprised with the slow response given their history of responding to vulnerabilities in the open source tools they package.