Malicious activity triggered automatic lockdown.
A ‘high volume of malicious activity across
Tor
exit nodes’ is believed to have been the reason why
Facebook
temporarily
blocked
access through
Tor
– an issue that has since been resolved.
Tor
is software that provides online anonymity by making Internet traffic pass through a number of nodes before reaching its final destination. Because the way the various connections are encrypted, none of the nodes can view both the source and the destination address at the same time.
Tor
is popular among privacy activists, as well as opposition members living under oppressive regimes, who use it both to anonymously communicate with each other and to bypass surveillance. The recent revelations of the PRISM surveillance network operated by the NSA is likely to give
Tor
‘s use a boost.
Security researchers are also frequent users of
Tor
, for instance to hide their location when investigating malicious activity on the Internet. But there is a third group that frequently uses
Tor
: cybercriminals. Because the destination cannot distinguish between different users of the
Tor
network, the crooks not only prevent their real IP address from being known, they reduce the chances of their activity being blocked.
Unless, of course, malicious activity from the
Tor
network becomes so bad that the destination service cannot but block access from all nodes. This is what has happened at
Facebook
. Although technical details have not been made public, it is generally possible to distinguish between traffic coming from
Tor
and other Internet traffic.
Tor
is a great service for enabling online anonymity. For some, it could make doing their job a little easier; for others using
Tor
could be a matter of life and death. But for the security community it also provides new challenges.
For those wanting to visit
Facebook
using
Tor
there is good news: access has been restored.
Posted on 19 June 2013 by
Martijn Grooten
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