Collected research

Creating a Rogue CA Certificate

Creating a rogue CA certificate

Alexander Sotirov, Marc Stevens, Jacob Appelbaum, Arjen Lenstra, David Molnar, Dag Arne Osvik and Benne de Weger · phreedom.org

Announcement of the 25C3 result in which an MD5 chosen-prefix collision was used against a commercial CA still signing with MD5, producing a rogue intermediate CA certificate trusted by every common browser. It can impersonate any HTTPS site, making phishing against banking undetectable. Links the write-up, slides, colliding certificates and a demo site.

Record

Document

Creating a rogue CA certificate

Researcher

Alexander Sotirov, Marc Stevens, Jacob Appelbaum, Arjen Lenstra, David Molnar, Dag Arne Osvik and Benne de Weger

Published by

phreedom.org

Topic

Crypto

In the archive

• Collected in the 2008 research round
• Ranked #1 in the 2009 Top 10 Web Hacking Techniques

Related sources

• MD5 Collisions and Rogue CA Slides
• Rogue CA certificate demonstration

Tags

• tls
• https
• phishing
• case-study
• hash-collision
• owasp-a02-2021
• owasp-a04-2021

This page is the archive's own catalogue record. The research is the work of Alexander Sotirov, Marc Stevens, Jacob Appelbaum, Arjen Lenstra, David Molnar, Dag Arne Osvik and Benne de Weger, first published at the original source. Preserved copies are kept so the citation survives its host; this one was last captured on 10 August 2026.