http://www.techworld.com/security/news/index.cfm?new
sID=6105
By Michael Crawford
Computerworld Today (Australia)
30 May 2006
Australian security firm Security Assessment has discovered
a flaw
with the install of the Windows-based Skype client.
Skype was notified of the potential flaw earlier this month
and
promptly issued a patch. General vulnerability dissemination
was made
on 22 May 2006 by Security Assessment.
The vulnerability, which has been confirmed by Skype, could
allow
users to "retrieve" files from other Skype users
through
unauthenticated connections, due to a flaw present in the
URI (Uniform
Resource Identifiers).
The flaw is enabled through the URI handler installed during
initiation of the Windows Skype client. It allows additional
command
line switches to be passed onto the Skype client,
potentially allowing
a file transfer.
For such a transfer to be initiated the attacker must
authorise the
victim, done easily through adding the victim to the
attacker's
contact list, which does not require authorisation from the
victim or
Skype user.
Drazen Drazic, managing director of Security Assessment said
the bug
affects all releases of Skype to Windows, up to and
including the
latest versions.
"We have had concerns about VoIP for a while, but
there are not too
many players in the space, security and otherwise,
addressing VoIP
security concerns," Drazic said.
"There have been a lot of products rolled out and
while only there are
a few large Australian implementations, risk review has been
an area
of research for us.
"We did not release the advisory until Skype got back
to us and
announced a patch which was Monday morning (22/05) last
week."
Exploitation of the flaw will only occur when the potential
victim
opens the URI exploit in Internet Explorer, which also
requires the
user to visit or open a compromised HTML page. The attacker
must also
know the location of the specific file on the intended
machine;
however, a common target would be the Skype configuration
file.
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