ExpressVPN has announced the open source implementation of the Lightway protocol, designed to achieve the fastest connection setup time while maintaining a high level of security and reliability. The code is written in C and distributed under the GPLv2 license. The implementation is very compact and fits in two thousand lines of code. Declared support for Linux, Windows, macOS, iOS, Android platforms, routers (Asus, Netgear, Linksys) and browsers. Assembly requires the use of Earthly and Ceedling assembly systems. The implementation is packaged as a library that you can use to integrate VPN client and server functionality into your applications.
The code uses out-of-the-box validated cryptographic functions provided by the wolfSSL library already used in FIPS 140-2 certified solutions. In normal mode, the protocol uses UDP to transfer data and DTLS to create an encrypted communication channel. As an option to handle unreliable or UDP-restricting networks, a more reliable, but slower, streaming mode is provided by the server, allowing data to be transferred over TCP and TLSv1.3.
Tests conducted by ExpressVPN have shown that compared to older protocols (ExpressVPN supports L2TP/IPSec, OpenVPN, IKEv2, PPTP, WireGuard, and SSTP, but the comparison was not detailed), switching to Lightway reduced connection setup time by an average of 2.5 times (in more than half of the cases, a communication channel is created in less than a second). The new protocol also made it possible to reduce the number of disconnections in unreliable mobile networks with connection quality problems by 40%.
The development of the reference implementation of the protocol will be carried out on GitHub with the opportunity to participate in the development of community representatives (to transfer changes, you need to sign a CLA agreement on the transfer of property rights to the code). Other VPN providers are also invited to cooperate, which can use the proposed protocol without restrictions.
The security of the implementation is confirmed by the result of an independent audit performed by Cure53, which at one time audited NTPsec, SecureDrop, Cryptocat, F-Droid and Dovecot. The audit covered the verification of source codes and included tests to identify possible vulnerabilities (issues related to cryptography were not considered). In general, the quality of the code was rated as high, but, nevertheless, the review revealed three vulnerabilities that can lead to a denial of service, and one vulnerability that allows the protocol to be used as a traffic amplifier during DDoS attacks. These problems have already been fixed, and the comments made on improving the code have been taken into account. The audit also drew attention to known vulnerabilities and issues in the third-party components involved, such as libdnet, WolfSSL, Unity, Libuv, and lua-crypt. Most of the issues are minor, with the exception of MITM in WolfSSL (CVE-2021-3336).
Source: opennet.ru