Baidu (BIDU) - Get Report, a Chinese-American web services company, revealed on Tuesday that a group of hackers attempted to steal its autonomous vehicle technology data.

The hackers are a gang called "hackers-for-hire" and have prompted Baidu to fortify its cyber security team.

"It's very difficult to know who employs them to do that, but we know someone tried to hire someone in the underground market to steal from us," Baidu's head of cyber security, Ma Jie said.

Baidu also has joined with rival tech firms Tencent (TCTZF) and Alibaba (BABA) - Get Report to combat the shared cybersecurity threat.

"The underground industry is getting bigger, and getting stronger so we must help each other against the whole underground industry," Ma said. "We're not enemies, they are the enemy.