The attacks usually start with a method to grab the user’s attention. This is often done with a status message
update on a friend’s Timeline, direct chat messages, or calendar event invitations. Newer attacks make use of IP
geo-location services, bringing in localized context such as the visitor’s city name. Other scams will display your
real name and some of your friend’s names to make the bait appear more credible. Clicking the link, or interacting
with the bait page, leads to another site that contains the payload of the attack. In 2011 Facebook started
to use third-party services like the Web of Trust URL reputation service to analyze any direct link leaving the
facebook.com domain. This means that if the scam is already well-known and classified, the URI will likely be on
Web of Trust’s blacklist and Facebook will warn the user when clicking on it. According to Facebook, they block
220 million messages with malicious links every day. Unfortunately these scams vary the URLs frequently so that
often there is no blocking rating for new scams when they first appear. Some of the newer services use heuristics
to block even previously unknown malicious links, but there will always be some URLs that are not blocked.
In order to bypass these filters, we have even seen attackers use cross-site scripting vulnerabilities on trusted
domains to forward to malicious pages.
The themes meant to trick users are often
reused. Popular ones include:
• Find out who viewed your profile or deleted
you from their account.
• Some shocking video or image of some
person or accident.
• Get free points for online games or gift
cards for various shops.
Most attacks discussed here require the
user to be logged into his or her account.
Since many users are permanently logged
into their accounts, or at least of the time
when seeing the bait messages, this prerequisite
is usually fulfilled.
We encourage users to report spam and scam messages to Facebook through the reporting button. This helps
preventing the scams from propagating further. Symantec will also work with Facebook to detect and alert users
to potentially malicious URLs on the site, helping to provide a safer experience for members