[liberationtech] Encrypted Pastebins: Attack Vectors against ezcrypt.it and 0bin.net
Synopsis: Hi, you may have seen the popularity rising of https://ezcrypt.it and its imitator https://0bin.net. These are services that let you encrypt a message using Javascript in your own browser, then pass on the encrypted contents for the service to store while you pass the decryption key your browser generated directly to the recipient using the #anchor part of the URL. You MUST not send it to the server. Once the recipient clicks on the URL her browser will keep the anchor on the client side, get the content and the necessary Javascript from the server and the Javascript will then access the anchor in order to decrypt the message in the browser. In other words, this is a pretty nifty way to use existing web technology to implement opportunistic end-to-end encryption. I can tell three attack vectors that an adversary can use - two active and a passive one - to gain access to the encrypted contents of the message. 1. Active local adversary attack: This is the more obvious one: An adversary gains access to the server and changes the Javascript or HTML code in such a way, that an unencrypted copy of the message is submitted to the server. The attacker can choose to do this only for specific targets in order to avoid getting caught. See http://secushare.org/end2end for more on these kind of attacks. 2. Local man in the middle attack: Similarly to attack 1, if the attacker cannot gain access to the server she can still intercept communications using false HTTPS certification and provide modified HTML or Javascript from there. You can protect your recipients against this kind of attack by having them install Certificate Patrol (see http://patrol.psyced.org). 3. Passive global adversary attack: Although we haven't seen any evidence yet, it is reasonable to assume that many computing facilities offering server hosting, housing and especially virtual machine hosting (VPS) have been compromised using Patriot legislation to offer a 24/7 surveillance access to authorities. See http://secushare.org/2011-FSW-Scalability-Paranoia for more information on this kind of attack. The authority can therefore access all encrypted messages being stored on the server passively as they move around server memory or virtual hard disk. In other words, once this infrastructure is in place with the computing center, there is no way for the server administrator to observe such kind of surveillance. Combined with the ability of a global adversary to evaluate the URLs as they are passed on through the Internet by means of e-mail or Facebook chat, the authority can extract the private key attached to the URL and apply it to the encrypted data obtained from the server in order to decrypt the message without showing up in the access logs of the server. Conclusion / Recommendation: There are safer ways to communicate privately: Pond, I2P, freenet, TorChat, RetroShare (see http://secushare.org/comparison). OTR and PGP not as much, but still better (see http://secushare.org/PGP for details). If you have the possibility to install such a software, do so. If you don't, try to at least pass the URL over a safe channel such as OTR. If that still isn't an option, then find a server that is very unlikely to be tapped by the authorities according to attack vector (3) and install the service from the available source codes. Remember to also protect yourself against attack vector (2) with certificate pinning practices. Sorry for spoiling this apparently easy solution, but the Internet is currently more broken than that. -- Liberationtech is public archives are searchable on Google. Violations of list guidelines will get you moderated: https://mailman.stanford.edu/mailman/listinfo/liberationtech. Unsubscribe, change to digest, or change password by emailing moderator at compa...@stanford.edu.
Re: [liberationtech] Encrypted Pastebins: Attack Vectors against ezcrypt.it and 0bin.net
On Mon, Jan 13, 2014 at 4:57 AM, carlo von lynX l...@time.to.get.psyced.org wrote: Sorry for spoiling this apparently easy solution, but the Internet is currently more broken than that. I don't think you're spoiling it. I use 0bin only for things I'd otherwise use a non-encrypted tool for... I'm sure some users make errors by assuming too much security there, but considering that the alternatives aren't 1/100th as accessible I'd have a hard time arguing that the tools aren't a net gain. They could perhaps be improved if they suggested a more secure alternative. -- Liberationtech is public archives are searchable on Google. Violations of list guidelines will get you moderated: https://mailman.stanford.edu/mailman/listinfo/liberationtech. Unsubscribe, change to digest, or change password by emailing moderator at compa...@stanford.edu.
[liberationtech] FW: An Internet for the Common Good: Engagement, Empowerment and Justice for All: A Community Informatics Declaration
An Internet for the Common Good: http://ci-journal.net/index.php/ciej/article/view/1099/1065 Engagement, Empowerment and Justice for All A Community Informatics Declaration Effective use of the Internet will benefit everyone. Currently the benefits of the Internet are distributed unequally: some people gain power, wealth and influence from using the Internet while others struggle for basic access. In our vision, people in their communities and everywhere - including the poor and marginalized in developing and developed countries, women and youth, indigenous peoples, older persons, those with disabilities -- will use the Internet to develop and exercise their civic intelligence and work together to address collective challenges. More than a technology or a marketplace, the Internet is a social environment, a community space for people to interact with the expectation that principles of equity, fairness and justice will prevail. Internet governance must ensure that this online social space functions effectively for the well-being of all. A community informatics approach to Internet governance supports equal distribution of Internet benefits and addresses longstanding social, economic, cultural and political injustices in this environment. Questions of social justice and equity through the Internet are central to how the Internet and society will evolve. People in different communities must be empowered to develop and adapt the Internet infrastructure to reflect their core values and ways of knowing. We support development of an Internet in which communities are the first mile and not the last mile. We believe the primary purpose of the Internet is not to mine data and make knowledge a commodity for purchase and sale but rather to advance community goals equally and fairly within these distributed infrastructures. We aspire to an Internet effectively owned and controlled by the communities that use it and to Internet ownership that evolves through communities federated regionally, nationally and globally. The Internet's role as a community asset, a public good and a local community utility is more important than its role as a site for profit-making or as a global artifact. The access layer and the higher layers of applications and content should be community owned and controlled in a way that supports a rich ecology of commercial enterprises subject to and serving community and public interests. As citizens and community members in an Internet-enabled world we have a collective interest in how the Internet is governed. Our collective interests need to be expressed and affirmed in all fora discussing the future of the Internet. As a collective, and as members of civil society, we have developed a declaration for Internet governance based on principles of community informatics. We appreciate your interest and welcome your support. A just and equitable Internet provides: 1. Fair and equitable means to access and use the Internet: affordable by all and designed and deployed so that all may realize the benefits of effective use. The poor and marginalized, women, youth, indigenous peoples, older persons, those with disabilities, Internet users and non-users alike; no one, from any community globally, should be without Internet access. 2. Equitable access within communities to the benefits of the Internet, including information, opportunities to communicate, increased effectiveness of communications and information management, and opportunities to participate in system development and content creation. Everyone, within all communities, should have the right, the means and the opportunity to use the Internet to share the full intellectual heritage of humankind without undue cost or hindrance. 3. Respect for privacy -- people must be able to conveniently use the Internet in a way that is credibly protected against large-scale surveillance or interference by government authorities or corporate interests. 4. Infrastructure that ensures the maximum level of personal security and reliability. 5. Opportunities for all within all communities to build, manage, and own Internet infrastructure as and when it is needed. 6. Internet governance by democratic principles and processes - including privileging input from communities affected by decisions and ensuring inclusion of the widest possible perspectives supporting the development of our digital environments. 7. A peer-to-peer architecture with equal power and privilege for each node or end point and complete neutrality of the architecture and medium for all users and all applications. 8. Recognition that the local is a fundamental building block of all information and communications and the global is a federation of locals. 9. Equal opportunity for all to connect and communicate in a language and culture of their choice. 10. Recognition and equal privileging of many types of knowledge and ways of
