Just a week after Apple was accused of downplaying highly critical vulnerabilties in its Mac OS X operating system, another series of "high risk" holes have been identified with still little or no effort by Apple to make its users aware.

Security company @stake reported new vulnerabilities in Mac OS X to Apple in March, and the company provided patches on 5 May.

However, the situation has remained virtually unknown until late Monday, nearly a week later, when the US government produced an advisory on the situation. This has since been followed by the UK government in its own advisory.

Apple meanwhile has added the critical security alerts to its obscure alerts page but provided no easily accessible information to its customers or made them aware of the issue.

To make matters worse, Apple news site MacWorld is reporting on a dangerous Trojan horse that has just appeared and pertains to be a demo of Word 2004 for Mac, due out soon.

Security company Intego - criticised last month for exaggerating the possible threat of another Trojan horse using a Mac vulnerability - confirmed that the file was malicious and wipes out a user's Home folder when opened. One victim told the site: "I downloaded the file in the hope that perhaps Microsoft had released some sort of public beta. The file unzipped, and to my delight the Microsoft icon looked genuine and trustworthy. I clicked on the installer file, and to my horror in 10 seconds the attachment had wiped my entire Home folder."

Apple, despite the trenchant support of its users, has now been accused by three highly respected security companies of knowingly downplaying critical security holes in its software, possibly in the hope of avoiding the huge negative publicity that has accompanied similar problems in Microsoft's Windows operating system.