To recap: Exposed to the public on Wednesday by the iOS hacking group Dev-Team, Jailbreakme.com 3.0 offers a simple way to jailbreak iPhones. Users can click on the app-like icon and 20 seconds later you've got a jailbroken phone, which allows you to run non-Apple approved apps.

Jailbreakme.com 3.0 exploits a vulnerability in the PDF reader. The iOS Safari browser downloads a PDF file that triggers a vulnerability in how the built-in PDF reader handles a certain font type. "This is what installs the actual jailbreak," explains Stephan Chenette, manager of security research at , a content security company.

So why is it so dangerous? An attacker can reverse engineer Jailbreakme.com 3.0 to silently install malicious code through the browser or email attachment. "Then the attacker could gain full control of the iPhone, iPad or other iOS device and install everything from a keylogger to a full-blown bot," Chenette says. "This isn't just limited to iPhones; iPad users need to be on the lookout, too."

that it is developing a fix for vulnerabilities on iOS 4. Critics have complained that Apple has been slow to respond to security problems, so Apple's quick response to Jailbreakme.com 3.0 underscores the severity of the vulnerability.

While you're waiting for the fix, Chenette offers four tips to keep your iPhones and iPads safe: