The PC version of Google Pack contains a Google Apps component, googleapps.exe, that, until earlier this week, was vulnerable to remote command injection. The Mac version of Google Pack is not affected because it does not contain the vulnerable component.
"We developed a fix for this issue earlier this week, and we're in the process of rolling it out to affected versions of Google Pack," a Google spokesperson said.
The PC version of Google Pack that's available online was repaired on Wednesday. Users who downloaded the software previously will receive a patch, if they haven't already, through Google's automatic updater.
According to Google's spokesperson, the issue was introduced as a result of code change four months ago, so users who downloaded Google Pack before then do not have the vulnerable component.
The vulnerability has to do with the way the "googleapps.url.mailto:" URI handles data, such as the "--renderer-path" argument.
Proof of concept code appears to have been posted on October 1, without prior disclosure to Google. The company found out about the exploit code the following day and says it isn't aware of attempts to exploit the flaw.
The scenario by which this vulnerability could be exploited requires several preconditions: a potential victim would have to visit a malicious Web site using Internet Explorer after having installed a vulnerable version of Google Pack with Google Chrome. The malicious site would initiate the attack, which would pass through Internet Explorer, the vulnerable Google Apps component, and Google Chrome.
Through remote command injection, the vulnerability could be used to launch an arbitrary batch file from a remote network share or to launch an arbitrary executable from the local system, according to the inline comments posted with the exploit code.
Were such an attack to take place -- an increasingly remote possibility as the patch percolates out -- it would affect the user's computer rather than Google's servers.
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