Review Note

Explain what was the exploitation used for Tarball. How can this be prevented in the future?

Tarball is a file that was created by the tar utility. Since tarball reads the user information, it stored these information, including /etc/pwd, into the heap of the memory. Although the memory chunk is freed afterwards, memory residue occured where the data for /etc/pwd is stored in the memory chunk. When the tar file is created, it then reads part of the data from the password file, hence revealing parts of the password to those having access to Tarball.

Solution: use calloc instead of malloc when initialising the memory chunk. This zeroes the memory chunk and hence removing the resources that were left by the previous process