Children as young as 11 years old are writing malicious computer code to hack accounts on gaming sites and social networks, experts have said.
A report from antivirus company AVG detailed evidence of programs written to "steal" virtual currency.
In one case, researchers were able to reverse-engineer "amateur" code to reveal data about the identity of one child in Canada.
The company said children must be educated on coding "rights and wrongs".
"As more schools are educating people for programming in this early stage, before they are adults and understand the impact of what they're doing, this will continue to grow." said Yuval Ben-Itzhak, chief technology officer at AVG.
The researchers found that many instances of malware targeting games popular with children shared the same characteristics.
Most were written using basic coding languages such as Visual Basic and C#, and were written in a way that contain quite literal schoolboy errors that professional hackers were unlikely to make - many exposing the original source of the code.