denial of service

Possible upcoming attempts to disable the Tor network

The Tor Project has learned that there may be an attempt to incapacitate our network in the next few days through the seizure of specialized servers in the network called directory authorities.

350 comments

New Tor Denial of Service Attacks and Defenses

New work on denial of service in Tor will be presented at NDSS '14 on Tuesday, February 25th, 2014:

19 comments

Upcoming Events

June 21, 2018 - June 22, 2018

The First Amendment for the 21st Century (Pittsburgh)

July 20, 2018 - July 22, 2018

HOPE (NYC)

July 24, 2018 - July 27, 2018

The 18th Privacy Enhancing Technologies Symposium (PETS)

July 24, 2018

Tor Community Night (Barcelona)

August 15, 2018 - August 17, 2018

USENIX (Baltimore)

See All Upcoming Events

Recent Updates

Tor 0.3.3.7 is released!

Hello, everyone!

We have a new stable release today. If you build Tor from source, you can
download the source code for 0.3.3.7 on the website. Packages
should be available within the next several weeks, with a new Tor Browser over the next several weeks.

Tor 0.3.3.7 backports several changes from the 0.3.4.x series, including fixes for bugs affecting compatibility and stability.

Changes in version 0.3.3.7 - 2018-06-12

Directory authority changes:
- Add an IPv6 address for the "dannenberg" directory authority. Closes ticket 26343.
Minor features (geoip):
- Update geoip and geoip6 to the June 7 2018 Maxmind GeoLite2 Country database. Closes ticket 26351.

Tor 0.3.4.2-alpha is released!

Hi! There's a new alpha release available for download. If you build Tor from source, you can download the source code for 0.3.4.2-alpha from the usual place on the website. Packages should be available over the coming weeks, with a new alpha Tor Browser release over the coming weeks.

Tor 0.3.4.2-alpha fixes several minor bugs in the previous alpha release, and forward-ports an authority-only security fix from 0.3.3.6.

Changes in version 0.3.4.2-alpha - 2018-06-12

Directory authority changes:
- Add an IPv6 address for the "dannenberg" directory authority. Closes ticket 26343.
Major bugfixes (security, directory authority, denial-of-service, also in 0.3.3.6):
- Fix a bug that could have allowed an attacker to force a directory authority to use up all its RAM by passing it a maliciously crafted protocol versions string. Fixes bug 25517; bugfix on 0.2.9.4-alpha. This issue is also tracked as TROVE-2018-005.

Meetup: Tor Community Night at PETS

Tor Browser 8.0a8 is released

Tor Browser 8.0a8 is now available from the Tor Browser Project page and also from our