[ISN] Mac OS fix fails to plug security hole

InfoSec News isn at c4i.org
Wed May 26 03:29:49 EDT 2004


By Robert Lemos 
Staff Writer 
CNET News.com
May 25, 2004

A security hole still threatens Mac OS X users after a patch issued by 
Apple Computer last week failed to fix the underlying problem, 
security experts said on Tuesday. 

The security issue could allow an attacker to transfer and then run a 
malicious program on a Mac, if the Mac's user can be enticed to go to 
a fake Web page on which the program has been placed. 

"This, in my mind, is the first critical vulnerability on OS X," said 
Richard Forno, a security researcher and the former chief of security 
for domain registrar Network Solutions. "Downloading the patch and 
seeing that there were some things that were fixed and some things 
that weren't, tells me that there is more work to be done." 

Two other software companies have confirmed the issue. Security 
information company Secunia raised its rating of the potential risk to 
"extremely critical" after determining that the vulnerability is more 
widespread than Apple apparently first thought. Independent software 
maker Unsanity released a tool this week to work around the problem 
and put out a white paper describing the issue. 

Apple would not comment. The company released the original patch 
Friday after news of the vulnerability appeared on the Internet. 

The vulnerability actually involves two flaws. One allows a Web site 
to place a file on the Mac's hard drive when a user clicks on a 
uniform resource locator, or URL, specifically designed to bypass Mac 
OS X's security. The other gives an attacker the ability to run a file 
on another user's computer, provided the location of the file is 
known. Used together, the flaws constitute a major security hole that 
could result in a potential instant-messaging or e-mail virus. 

Perhaps the biggest problem is that there seems to be no easy 
solution, Jason Harris, a programmer for Unsanity, wrote in the 
company's white paper. 

"There's lots of overlap between useful applications of this 
functionality and malicious ones, meaning that Apple can't easily fix 
this without removing useful features from its operating system and 
from existing apps," he wrote. 

The issue is the first major security problem for Mac OS X that has 
not been caused by the operating system's underlying Unix roots. 
Previously, Mac OS X has mainly had to patch problems that affected 
FreeBSD, the Unix-like operating system on which it is based. However, 
the current issue is in the code that the company built on top of that 

Forno maintains that the Mac is more secure than Windows but stressed 
that this problem should have been caught in testing before the 
operating system had shipped. Moreover, in light of the goofed patch 
and previous issues with Apple downplaying security problems, he said 
the company needs to start being more proactive about security. 

"Apple is coming to terms with dealing with these types of issues, 
"Forno said. 

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