Obviously the feature is one that Apple software experts designed specifically for malware writers, perhaps seeing them as an untapped market.

The bug in the latest version of Apple's OS X allows attackers root user privileges with a micro code which could be packed into a message.

Security researcher Stefan Esser said that this was the security hole attackers regularly exploit to bypass security protections built into modern operating systems and applications.

The OS X privilege-escalation flaw stems from new error-logging features that Apple added to OS X 10.10. Plainly the software genii did not believe that standard safeguards involving additions to the OS X dynamic linker dyld applied to them because they were protected from harm by Steve Job's ghost.

This means that attackers to open or create files with root privileges that can reside anywhere in the OS X file system.

"This is obviously a problem, because it allows the creation or opening (for writing) of any file in the filesystem. And because the log file is never closed by dyld and the file is not opened with the close on exec flag the opened file descriptor is inherited by child processes of SUID binaries. This can be easily exploited for privilege-escalation," Esser said.

The vulnerability is present in both the current 10.10.4 (Yosemite) version of OS X and the current beta version of 10.10.5. Importantly, the current beta version of 10.11 is free of the flaw, an indication that Apple developers may already be aware of the vulnerability.

An Apple spokesman said that engineers are aware of Esser's post of course they did not say they would do anything about it. They will have to go through the extensional crisis involved in realising that their product was not secure or perfect. Then the security team will have to issue orders, signed in triplicate, sent in, sent back, queried, lost, found, subjected to an internal inquiry, lost again, and finally bury it in soft peat for three months and recycled as firelighters.