Moxie Marlinspike

Research

SSL stripping In a 2009 paper, Marlinspike introduced the concept of SSL stripping, a man-in-the-middle attack in which a network attacker could prevent a web browser from upgrading to an SSL connection in a way that would likely go unnoticed by a user. He also announced the release of a tool, sslstrip, that would automatically perform these types of man-in-the-middle attacks. The HTTP Strict Transport Security (HSTS) specification was subsequently developed to combat these attacks.

SSL implementation attacks Marlinspike has discovered a number of different vulnerabilities in popular SSL implementations. Notably, he published a 2002 paper on exploiting SSL/TLS implementations that did not correctly verify the X.509 v3 "BasicConstraints" extension in public key certificate chains. This allowed anyone with a valid CA-signed certificate for any domain name to create what appeared to be valid CA-signed certificates for any other domain. The vulnerable SSL/TLS implementations included the Microsoft CryptoAPI, making Internet Explorer and all other Windows software that relied on SSL/TLS connections vulnerable to a man-in-the-middle attack. In 2011, the same vulnerability was discovered to have remained in the SSL/TLS implementation on Apple Inc.'s iOS. Also notably, Marlinspike presented a 2009 paper in which he introduced the concept of a null-prefix attack on SSL certificates. He revealed that all major SSL implementations failed to properly verify the Common Name value of a certificate, so that they could be tricked into accepting forged certificates by embedding null characters into the CN field.

Solutions to the CA problem In 2011, Marlinspike presented a talk, "SSL And The Future Of Authenticity", at the Black Hat security conference in Las Vegas. He outlined many of the problems with certificate authorities and announced the release of a software project called Convergence to replace them. In 2012, Marlinspike and Perrin submitted an Internet Draft for TACK, which is designed to provide SSL certificate pinning and help solve the CA problem, to the Internet Engineering Task Force.

Cracking MS-CHAPv2 In 2012, Marlinspike and David Hulton presented research that makes it possible to reduce the security of MS-CHAPv2 handshakes to a single DES encryption. Hulton built hardware capable of cracking the remaining DES encryption in less than 24 hours, and the two made the hardware available for anyone to use as an Internet service.

Mobily surveillance controversy In 2013, Marlinspike published emails on his blog that he claimed were from Saudi Arabian telecom service Mobily soliciting his help in surveilling their customers, including intercepting communications running through various applications. Marlinspike refused to help, making the emails public instead. Mobily denied the allegations. "We never communicate with hackers", the company said.

Traveling Marlinspike says that when flying within the United States he is unable to print his own boarding pass, is required to have airline ticketing agents make a phone call in order to issue one, and is subjected to secondary screening at TSA security checkpoints.

While entering the U.S. on a flight from the Dominican Republic in 2010, Marlinspike was detained by federal agents for nearly five hours, all his electronic devices were confiscated, and at first agents claimed he would only get them back if he provided his passwords so they could decrypt the data. Marlinspike refused to do this, and the devices were eventually returned, though he noted that he could no longer trust them, saying, "They could have modified the hardware or installed new keyboard firmware."

Recognition In 2016, Fortune magazine named Marlinspike among its 40 under 40 for being the founder of Open Whisper Systems and "[encrypting] the communications of more than a billion people worldwide". Wired also named him to its "Next List 2016," as one of "25 Geniuses Who Are Creating the Future of Business." In 2017, Marlinspike and Perrin were awarded the Levchin Prize for Real World Cryptography "for the development and wide deployment of the Signal protocol".

Personal life Originally from the state of Georgia, In 2004, he bought a derelict sailboat and, with three friends, refurbished it and sailed around the Bahamas while making a "video zine" about their journey called Hold Fast. and "The Promise of Defeat."