CWE-120 Classic Overflow

Given an input buffer, data is copied without checking its size.

• If destination buffer is larger than input data, nothing bad happens.

• If destination buffer is smaller than input data, memory is overwritten.

Impact

Memory is overwritten.

• Mostly affects local variables.

• May change the execution flow.

  • Change of local control variables.

  • Change of stored Instruction Pointer.

• May be used to inject external code.

Solution

Take in consideration the size of the destination buffer!