A security administrator examines a network session to a compromised database server with a packet
analyzer. Within the session there is a repeated series of the hex character 90 (x90).
Which of the following attack types has occurred?
The hex character 90 (x90) means NOP or No Op or No Operation. In a buffer overflow attack, the buffer can
be filled and overflowed with No Op commands.
A buffer overflow occurs when a program or process tries to store more data in a buffer (temporary data
storage area) than it was intended to hold. Since buffers are created to contain a finite amount of data, the extra
information – which has to go somewhere – can overflow into adjacent buffers, corrupting or overwriting the valid
data held in them. Although it may occur accidentally through programming error, buffer overflow is an
increasingly common type of security attack on data integrity. In buffer overflow attacks, the extra data may
contain codes designed to trigger specific actions, in effect sending new instructions to the attacked computer
that could, for example, damage the user’s files, change data, or disclose confidential information. Buffer
overflow attacks are said to have arisen because the C programming language supplied the framework, and
poor programming practices supplied the vulnerability.