Facebook temporarily blocks access from Tor

Posted by   Virus Bulletin on   Jun 19, 2013

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



Latest posts:

VB2019 paper: Domestic Kitten: an Iranian surveillance program

At VB2019 in London, Check Point researchers Aseel Kayal and Lotem Finkelstein presented a paper detailing an Iranian operation they named 'Domestic Kitten' that used Android apps for targeted surveillance. Today we publish their paper and the video…

VB2019 video: Discretion in APT: recent APT attack on crypto exchange employees

At VB2019 in London, LINE's HeungSoo Kang explained how cryptocurrency exchanges had been attacked using Firefox zero-days. Today, we publish the video of his presentation.

VB2019 paper: DNS on fire

In a paper presented at VB2019, Cisco Talos researchers Warren Mercer and Paul Rascagneres looked at two recent attacks against DNS infrastructure: DNSpionage and Sea Turtle. Today we publish their paper and the recording of their presentation.

German Dridex spam campaign is unfashionably large

VB has analysed a malicious spam campaign targeting German-speaking users with obfuscated Excel malware that would likely download Dridex but that mostly stood out through its size.

Paper: Dexofuzzy: Android malware similarity clustering method using opcode sequence

We publish a paper by researchers from ESTsecurity in South Korea, who describe a fuzzy hashing algorithm for clustering Android malware datasets.

We have placed cookies on your device in order to improve the functionality of this site, as outlined in our cookies policy. However, you may delete and block all cookies from this site and your use of the site will be unaffected. By continuing to browse this site, you are agreeing to Virus Bulletin's use of data as outlined in our privacy policy.