Alex Ionescu

IRL Name: 
Alex Ionescu

Alex Ionescu was born on April 26th, 1986, in the city of Bucharest, Romania. Son of a doctor and an engineer, he took up a passion with computers at the age of six, when he first hacked DOS 4.00's command line parser unsuccessfully until the age of seven, when he discovered hex editing. At that time, he was already fluent in QBASIC and was working on password protection programs and graphical shells.

He has been active in the area of NT Kernel Development, offering help and advice for driver developers, as well as in the NT Reverse Engineering/Security field, where he has published a number of articles and source code, such as on the topic of NTFS Advanced Data Streams.

He was the lead kernel developer for ReactOS, an open source clone of Windows XP/2003 written from scratch, where he wrote most of the NT-based kernel. Alex is also very active in the security research community, discovering and reporting several vulnerabilities related to the Windows kernel and presenting talks at conferences such as Blackhat and Recon. In the last three years, he has also contributed to patches and development in two major commercially used operating system kernels.


He is the co-author of Windows Internals 5th edition.

He was the Lead Developer of the Outlook Express plugin.

His contributions include documentation for the Linux NTFS project, various award-winning articles on Planet Source Code and an extensive research paper on the Visual Basic Metadata and Pseudo-code format.

He is also the TinyKRNL Project Coordinator.