Make sure you have version 220.127.116.11 or higher. (If you don't use Flash, go read Alex Wolfe's post on Joomia. Looks like really cool stuff.)
If you don't do these things, you run the risk of coming across a malicious SWF (Shockwave Flash) file, which could really happen from just about anywhere. That's one of the things that makes these types of attacks so risky. The attackers are currently attempting to install malware and Trojans on at-risk systems designed to pilfer passwords. But since these exploits are targeting a buffer overflow vulnerability (thanks for not checking your inputs, Mr. Adobe Developer), attackers could probably do whatever they so choose to your system. At first, researchers thought this was a zero-day attack; now they're leaning toward the possibility that these attacks are targeting a flaw discovered and detailed by Mark Dowd at IBM a few weeks back.
Symantec offers a rather convoluted analysis of the vulnerability and attacks to date here. For those not interested in deconstructing these sort of events, the takeaway is that Symantec advises disabling or uninstalling Flash until this mess is sorted out. They also mention setting a kill bit on CLSID d27cdb6e-ae6d-11cf-96b8-444553540000. But setting kill bits requires adult supervision, and I wouldn't advise doing this unless you really know what you're doing.
If you're a Firefox user, consider installing NoScript. It's perfect for days like this.