David Sun

  • Principal


David is a principal with CliftonLarsonAllen LLP and national leader for the cyber incident response and forensics practice.  He has 25 years of experience responding to data breach and privacy incidents, internal employee malfeasance and government agency investigations for both public and private sector clients.

David assists clients with ransomware attacks, ransom negotiation and payment, email compromise, wire fraud, forensic analysis and reconstruction and post-breach remediation.  In addition, he has conducted hundreds of computer investigations surrounding departing employee activity, destruction of documents and unauthorized system access.  Lastly, David utilizes his vast experience in system compromises and assists clients with creating effective cybersecurity programs to improve data and systems security.

David is a practical problem solver and technologist who can describe technology-related issues in understandable terms to attorneys, judges, and juries.  He has served as an expert on numerous high-profile matters involving class action data breach litigation, regulatory investigations of data privacy violations, intellectual property theft and corporate malfeasance.  Publicly cited examples of his work include the Secretary of State Hillary Clinton e-mail server controversy and destruction of public records by sitting New Orleans Mayor C. Ray Nagin.

David is a testifying expert in federal and state courts in the areas of computer forensics and cybersecurity and he has served as a court appointed independent expert in these fields.  Past accomplishments also include conducting security assessments for the United Nations and various United States Federal Reserve Banks and securing the 2004 Summer Olympics in Athens, Greece.  He also previously served as an Adjunct Professor at George Mason University and is routinely a faculty member for the Virginia and Massachusetts State Bars’ continuing education programs.  David has multiple patents and publications in the field of Computer Forensics.


  • Master of Science in Electrical Engineering, Virginia Tech
  • Bachelor of Science in Electrical Engineering, Virginia Tech