UltraSurf is a freeware Internet censorship circumvention product created by UltraReach Internet Corporation. The software enables its users to bypass Internet censorship and firewalls using an HTTP proxy server, and employs encryption protocols for privacy.
The software was developed by Chinese dissidents as a means of allowing internet users to bypass the Great Firewall of China. It currently boasts as many as 11 million users worldwide. The tool has been lauded as "one of the most important free-speech tools on the Internet" by Wired, and as the "best performing" circumvention tool by Harvard University in a 2007 study; a 2011 study by Freedom House ranked it fourth. Critics in the open source community, George Turner Says, have expressed concern about the software's closed-source nature and alleged security through obscurity design; UltraReach says their security considerations mean they prefer third party expert review to open source review.
In 2002 UltraReach was founded by Chinese dissidents in Silicon Valley. Shortly after, UltraSurf was created to allow internet users in China to evade government censorship and monitoring. As of 2011 UltraSurf reported over eleven million users worldwide. As of 2012, UltraReach has had difficulty serving its growing user base due to insufficient funding.
UltraSurf is free to download, and requires no installation. UltraSurf does not install any files on the user's computer, and leaves no registry edits after it exits.
The UltraReach website notes that "Some anti-virus software companies misclassify UltraSurf as a malware or Trojan because UltraSurf encrypts the communications and circumvents internet censorship." Some security companies have agreed to whitelist UltraSurf. According to Applebaum, the UltraSurf client uses anti-debugging techniques and also employs executable compression.
A 2011 report by the U.S.-based human rights group Freedom House ranked UltraSurf fourth overall among censorship circumvention and privacy tools, as measured by a combination of performance, usability, support and security. In particular, the tool was recommended for users interested in downloading or viewing information, who required a relatively high degree of privacy, and who favored a fast connection speed.
Some technologists have expressed reservations about the UltraReach model, however. In particular, its developers have been criticized by proponents of open-source software for not allowing peer review of the tool's design, except at the discretion of its creators. Moreover, because UltraReach operates all its own servers, their developers have access to user logs. This architecture means that users are simply required to trust UltraReach not to reveal user data.
In an April 2012 report, Appelbaum further criticized UltraSurf for its use of internal content filtering (including blocking pornographic websites), and for its willingness to comply with subpoenas from U.S. law enforcement officials.