During his time at iSEC Partners, Stamos was well known for his research publications on vulnerabilities in forensics software[5] and MacOS,[6] Operation Aurora,[7] and security ethics in the post-Snowden era.

[8] Stamos was an expert witness for a number of cases involving digital privacy, encryption, and free speech: iSEC Partners was acquired by NCC Group in 2010.

Our analysis suggests these accounts and Pages were affiliated with one another and likely operated out of Russia.Following disagreement with other executives about how to address the Russian government's use of its platform to spread disinformation during the 2016 U.S. presidential election, he made plans in 2018 to leave the company[2] to take a research professorship at Stanford University.

[25][26] During Stamos's tenure as the Chief Security Officer, Facebook was involved in numerous safety and security controversies including the Russian interference in the 2016 United States elections, failure to remove reported child-abuse images,[27] inaction against disinformation campaigns in Philippines that targeted and harassed journalists, [28][29] Facebook–Cambridge Analytica data scandal and the Rohingya genocide, for which the company has played a "determining role" according to the UN.

[33] In July 2019, Facebook agreed to pay $100 million to settle with the U.S. Securities and Exchange Commission for misleading investors for more than two years (2015-2018) about the misuse of its users' data.