David Sun
Principal, Cybersecurity

David Sun leads the security incident response and recovery services and computer forensic and litigation support services for CohnReznick’s Cybersecurity practice. He also develops comprehensive cloud security service offerings that provide clients with access to end-to-end suite of cybersecurity, technology risk, and privacy services. 

David has 25 years of cybersecurity and IT management experience responding to data breach and privacy incidents, internal employee malfeasance, and government agency investigations. His expertise is in responding to cyber-attacks and resuming business operations; investigating email compromises, data breaches, and multi-million-dollar losses from wire fraud; performing forensic analysis, reconstruction, and post-breach remediation; and prosecuting departing employees for theft of sensitive information, destruction of documents, and unauthorized activities.

As a leading industry consulting expert specializing in describing technology-related issues, David has served a testifying expert or court appointed expert on hundreds of litigation matters. This includes providing expert testimony during a national federal investigation into the handling of classified information; offering guidance during an investigation into destruction of public records by a sitting mayor of a major city; providing security assessments for the United Nations and various United States Federal Reserve Banks; assisting multiple state attorneys general investigate a variety of data privacy violations; and more. 

Before joining CohnReznick, David was the founder and president of SunBlock Systems, Inc., a global litigation advisory firm that specialized in electronic evidence. Through two subsequent acquisitions, he joined a major accounting and advisory firm as a principal and its national practice leader for cyber incident response and forensics. In this role, he was responsible for leading a team of professionals responding to data breaches and ransomware attacks and conducting employee malfeasance and government agency investigations for both public and private sector clients. David also provided a suite of proactive cybersecurity services to help mitigate the risk of a cyber-attack.


BS, Electrical Engineering, Virginia Tech

MS, Electrical Engineering, Virginia Tech


Certified Computer Examiner (CCE)

Certified Information Systems Security Professional (CISSP)

EnCase Certified Examiner (EnCE)


The International Society of Forensic Computer Examiners 

The International Information Systems Security Certification Consortium (ISC2)

High Technology Crime Investigation Association (HTCIA) 

International Association of Computer Investigative Specialists (IACIS)  


The Consulting Report’s Top 50 Cybersecurity Consultants and Leaders of 2023

Areas of expertise


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Sun joins CohnReznick as Principal, Cybersecurity