[Note] changing the random bit value of the memory steals information from the smart card.

A student at Princeton University in the United States took advantage of a lightbulb, some known features on the computer memory, coupled with a little luck, made Java and. Net Virtual Machine security issues apparent.

Sudhakar Govindavajhala, a recent Princeton University graduate, asserted on Tuesday (May 13) that attacks on computers usually require physical access to computers when demonstrating the process in Berkeley, California, therefore, this technique does not pose a major threat to virtual machines running on PCs and servers. However, such attacks can be used to steal data from smart cards.

This technique relies on the memory's "flip bits ). Occasionally emitted cosmic rays may cause random bits in the memory to change from 0 to 1 or from 1 to 0. Govindavajhala does not stop. He uses a light bulb to bake a chip in a computer, resulting in more memory bits.

Through the above experiments, the college student broke the security mode on which the Virtual Machine relies: that is, the computer faithfully executes the Issued commands.

Govindavajhala attacks the system by adding its code to the memory and filling the remaining memory space with the new Code address. He found that if these addresses are used to fill up 60% of the memory, the random abnormal bit will make his attack code run within 70% of the time. In other cases, key programs on the computer will be paralyzed.

Govindavajhala's techniques can be used to steal data from smart cards because these seemingly credit card items have memory and a simple processor.