Remote code execution vulnerabilities in modern PHP applications have become more difficult to find and exploit due to better education of developers and the wide adoption of Suhosin, web application firewalls and other PHP environment hardening. E.g. the class of remote file inclusion vulnerabilities is practically dead in modern PHP installations.
This talk will demonstrate how a well known class of PHP application vulnerabilities that is widely believed to be a DoS vulnerability only, can result in arbitrary PHP code being executed. Furthermore it will be demonstrated how attacks on PHP applications can be tunneled through web application firewalls like mod_security with ease, bypassing the whole rule engine. And last but not least we will take a look at the recently introduced protections against interruption vulnerabilities in PHP and how it is still possible to perform post exploitation tricks as presented at Syscan and Blackhat.
Stefan Esser will show a PHP application 0-day, a mod_security bypass 0-day, and 0-day tricks to still perform interruption vulnerabilities.
Stefan Esser is best known in the security community as the PHP security guy. Since he became a PHP core developer in 2002 he devoted a lot of time to PHP and PHP application vulnerability research. However in his early days he released lots of advisories about vulnerabilities in software like CVS, Samba, OpenBSD or Internet Explorer. In 2003 he was the first to boot linux directly from the harddisk of an unmodified XBOX through a buffer overflow in the XBOX font loader. In 2004 he founded the Hardened-PHP Project to develop a more secure version of PHP, known as Hardened-PHP, which evolved into the Suhosin PHP Security System in 2006. Since 2007 he works as head of research and development for the german web application company SektionEins GmbH that he co-founded. He was a speaker of POC2008 and Black Hat USA 2009.