Apple "secretly" updated anti-malware protection in Mac OS X when it launched a new version this week, IT security firm Sophos has claimed.
The Cupertino company allegedly added "limited protection" against a backdoor Trojan known to Apple as HellRTS, Sophos suggested, but the iPhone and MacBook manufacturer did not mention the update either in a security advisory or in the release notes accompanying Mac OS X 10.6.4.
This piece of malware can allow malicious attackers to gain control over Mac systems, the security company said.
Sophos claimed that Apple updated a file named XProtect.plist, which contained "elementary signatures" of a number of Mac threats, to detect HellRTS.
"It's almost as if they [Apple] don't want to acknowledge that there could be a malware threat on Mac OS X," said Graham Cluley, senior technology consultant at Sophos, in a statement.
Cluley did point out, however, that it was positive Apple had updated Mac OS X security, as the Trojan can allow hackers to send spam email from a victim's computer, take screenshots of what they are doing and access files.
"Unfortunately, many Mac users seem oblivious to security threats which can run on their computers, even though Apple has now built-in some elementary protection," Cluley added.
"This lack of awareness isn't helped when Apple issues an anti-malware security update by stealth, rather than informing the public what it has done."
Apple told IT PRO that it had nothing further to say on the matter, other than what was on its security update page. At the time of publication, the company had not given a response as to whether the updated protection is "limited", as Sophos has claimed.
As for how the security is lacking, Cluley told IT PRO that he believes that the anti-virus on Mac OS X will only intercept malware if a user has downloaded it to their computer and then tried to run the file from their desktop.
If the malware comes via a USB stick, for example, the protection misses the threat, Cluley claimed.
