Amit Klein

This is my academic website. For my non-academic website, click here

Amit Klein

I research the security of network protocols and their implementations, and web applications security.

Email: aksecurity@gmail.com



I am a post-doctorate researcher at the School of Computer Science and Engineering, the Hebrew University of Jerusalem, hosted by Prof. Michael Schapira.

Research Interests

  • Security of network protocols (specifically layers 3-4 and auxiliary protocols) and their implementations.
  • The security impact of unsafe (concurrency-wise) implementations of PRNG algorithms.
  • Web application security.


Short bio
Prior to the Hebrew University, I completed a Ph.D. in Computer Science in Bar Ilan University, supervised by Prof. Benny Pinkas. Prior to that, I spent more than 20 years in the cyber security startups, mostly in executive positions (VP Security Research for Safebreach, CTO of Trusteer, Chief Scientist for Cyota, Director of Security for Sanctum). I am a graduate of the IDF Talpiot Programme, with B.Sc. in Mathematics (major) and Physics (major), magna cum laude, from the Hebrew University.


Honors and Awards

  • 1st Place, Cyber Security Awareness Week (CSAW) 2020 Applied Research Regional Competition for the paper “Flaw Label: Exploiting IPv6 Flow Label”, J. Berger, A. Klein, B. Pinkas.
  • 1st Place, Cyber Security Awareness Week (CSAW) 2019 Applied Research Regional Competition for the paper “From IP ID to Device ID and KASLR Bypass”, A. Klein, B. Pinkas.
  • INFOCOM 2017 “Best in Session” Award for the paper “Internet-wide study of DNS cache injections”, A. Klein, H. Shulman, M. Waidner.
  • Hebrew University Rector Prize, 1990.
  • Hebrew University Math and Sciences Dean Prize, 1991.


Academic Service

  • Referee, Cyber Security Awareness Week (CSAW) 2018 Applied Research Regional Competition, 2018.
  • Program committee member, “Security, Privacy, Trust and Abuse” track, WWW2012, 2012.
  • Program committee member, WOOT’11 (5th USENIX Workshop on Offensive Technologies), 2011.


(see also in Google Scholar and DBLP)

Academic publications:


  • Amit Klein. “Subverting Stateful Firewall with Protocol States”. 29th Annual Network and Distributed System Security Symposium (NDSS 2022). Extended version is available here
  • Amit Klein. “Cross Layer Attacks and How to Use Them (for DNS Cache Poisoning, Device Tracking and More)”. 2021 IEEE Symposium on Security and Privacy (SP).
  • Amit Klein, Elias Heftrig, Haya Shulman, and Michael Waidner. “Blackbox caches fingerprinting”. CoNEXT ’20: The 16th International Conference on emerging Networking EXperiments and Technologies.
  • Jonathan Berger, Amit Klein, and Benny Pinkas. “Flaw Label: Exploiting IPv6 Flow Label”. 2020 IEEE Symposium on Security and Privacy (SP).
  • Amit Klein and Benny Pinkas. “From IP ID to Device ID and KASLR Bypass”. 28th USENIX Security Symposium (USENIX Security 19). Extended version is available here.
  • Amit Klein and Benny Pinkas. “DNS Cache-Based User Tracking”. 26th Annual Network and Distributed System Security Symposium, NDSS 2019.
  • Markus Brandt, Tianxiang Dai, Amit Klein, Haya Shulman, and Michael Waidner. “Domain Validation++ For MitM-Resilient PKI”. 2018 ACM SIGSAC Conference on Computer and Communications Security. CCS ’18.
  • Amit Klein, Vladimir Kravtsov, Alon Perlmuter, Haya Shulman, and Michael Waidner. “POSTER: X-Ray Your DNS”. 2017 ACM SIGSAC Conference on Computer and Communications Security, CCS 2017.
  • Amit Klein, Haya Shulman, and Michael Waidner. “Counting in the Dark: Caches Discovery and Enumeration in the Internet”. IEEE/IFIP International Conference on Dependable Systems and Networks (DSN).
  • Amit Klein, Haya Shulman, and Michael Waidner. “Internet-wide study of DNS cache injections”. 2017 IEEE Conference on Computer Communications, INFOCOM 2017.
  • Yonit Kesten, Amit Klein, Amir Pnueli, and Gil Raanan. “A Perfecto Verification: Combining Model Checking with Deductive Analysis to Verify Real-Life Software”. FM’99 - Formal Methods, World Congress on Formal Methods in the Development of Computing Systems.
  • Amit Klein. “Web Cache Poisoning Attacks”. Encyclopedia of Cryptography and Security.

Non-academic publications:


2015 – Safebreach (enterprise security software).
Vice President, Security Research (part time).
Thought-leadership security research.
2013 – 2015 IBM Trusteer (acquired company).
Chief Technology Officer.
Product content expertise and innovation leadership.
2006 – 2013 Trusteer (financial malware fraud detection and prevention for banks, acquired by IBM for $650,000,000).
Chief Technology Officer.
Management of the security research group. Grew the research group from 0 to 20 researchers.
2005 – 2006 RSA Security, Cyota Division (acquired company).
Chief Scientist.
Innovation, patents and new technology.
2004 – 2005 Cyota (anti online-banking fraud SaaS startup, acquired by RSA for $145,000,000).
Chief Scientist.
Innovation, patents and new technology.
1997 – 2004 Sanctum (web application security startup, acquired by Watchfire which was in turn acquired by IBM).
Director of Security Research.
Management of the product security content team.
1995 – 1997 Israeli Ministry of Defense.
Software Project Manager.
Management of software and network security projects.
1991 – 1994 Israel Defense Forces.
Research officer (Captain) in the Signal Corps.
Research in applied computer science and mathematics.


  • Fall 2021: Lecturer, “Securing Information Systems” (3004), Reichmann University (IDC).
  • Fall 2020: Teaching Assistant, “Cryptography Workshop” (89695), Bar Ilan University.