That's a huge number that I find very difficult to believe. I would wager ZoneAlarm's study likely only looked at Facebook accounts belonging to users whose computers were already infected with malware. This would tip the scales since such individuals most likely have friends who are also most likely to click and spread viruses on the social network.
Either way, the bottom part of the infographic is the most important. Here is what ZoneAlarm recommends you do to protect yourself:
Create a strong password.
Don't accept unknown friend requests.
Monitor what your friends are sending and sharing with you.
Turn on https:// browsing in your Facebook settings.
Don't click on suspicious links.
Download Facebook security software.
The last point is of course the reason ZoneAlarm created this infographic in the first place. The company sells a product called ZoneAlarm SocialGuard, which has the slogan "Advanced Facebook Security." It costs $20 per year. Here is what you get:
Prevent hacked account disasters: SocialGuard constantly scans your Facebook account and notifies you instantly by e-mail and text alerts when it detects signs of hacking.
Know if strangers are lurking: Are strangers hiding in your social network? Let SocialGuard identify these folks and alert you before you get into trouble.
Avoid dangerous links: 20% of newsfeed links open viruses or imposter sites that steal your info. SocialGuard warns you of dangerous links in your newsfeed, on your wall, and in your private Facebook messages.
Get real-time alerts: Address dangers immediately. Get notified through e-mail and texts when problems are detected – even when you are away from Facebook.
Detect cyberbullies and predators: SocialGuard scans for alarming words in private messages, status updates, and wall postings and also flags "friends" who may be much older than they claim to be.
Notice how the third point seems to say that the 20 percent number includes more than just viruses: the links could also lead to fraudulent sites made by scammers. This makes me even more suspicious of the validity of ZoneAlarm's claim.
Regardless of what percentage of links are malicious on Facebook, I don't think you need Facebook-specific security software to protect you. Just follow one simple rule: don't click on suspicious links, regardless of who is sharing them.
Update: Facebook contacted me to clarify the "600,000 logins are compromised every day" bit. I purposefully avoided mentioning it in the article since I remembered that statistic was incorrectly quoted when it was first mentioned a few months ago. The only part of the infographic that actually appears to come from ZoneAlarm is what's in the title (that's why I put it there), but again, ZoneAlarm didn't provide details and Facebook didn't think it was worth discussing.
"While Facebook does block ~600k logins per day, it is not that these Facebook accounts are compromised on Facebook, and certainly not that they're 'hacked,'" a Facebook spokesperson said in a statement. "Compromised in this sense refers to logins where we are not absolutely confident that the account's true owner is accessing the account and we either preemptively or retroactively block access. We are being preventative and helping make sure people secure their account even if they aren’t actually compromised on Facebook."