Chris Sestito

Chris “Tito” Sestito is co-founder and CEO of HiddenLayer, an Austin, Texas, company that protects machine learning models from attack. A threat researcher by background, he led Cylance’s response after its AI malware detector was tricked, and he has argued since then that models need their own security tools.

Threat research at Qualys and Cylance

Sestito was director of threat research at Cylance and vice president of engineering at Qualys. In 2019 an attack showed that appending harmless code to malicious files could get Cylance’s model to wave them through. “We led the relief effort after our machine learning model was attacked directly through our product, and realized this would be an enormous problem for any organization deploying ML models in their products,” he said when HiddenLayer launched its first product.

Founding HiddenLayer in Austin

He co-founded HiddenLayer in 2022 with Tanner Burns and Jim Ballard, colleagues from Qualys, Cylance, and BlackBerry. Its approach watches the inputs going into a model and the predictions coming out, looking for patterns that suggest someone is probing or tampering with it, without needing the customer’s raw training data. He told TechCrunch that adversarial attacks “are not loud like ransomware” and that “you have to be looking for them to catch them in time.”

In 2023 HiddenLayer won the RSA Conference Innovation Sandbox contest, the conference’s annual pitch competition for security startups, beating nine other finalists.

Treating models as an attack surface

Sestito’s case is that companies have spent heavily on machine learning without defending it. Adversarial attacks, he told TechCrunch, can cause “all of the same damage we’ve seen in traditional cyber attacks including exposing customer data and destroying production systems.” As he put it, “With any new technology comes new attack vectors; this is the same fight on a new frontier.”