Explanation/Reference:
Explanation:
Buffer overflows are in the source code of various applications and operating systems. They have been around since programmers started developing software. This means it is very difficult for a user to identify and fix them. When a buffer overflow is identified, the vendor usually sends out a patch, so keeping systems current on updates, hotfixes, and patches is usually the best countermeasure.
A buffer overflow takes place when too much data are accepted as input to a specific process. A buffer is an allocated segment of memory. A buffer can be overflowed arbitrarily with too much data, but for it to be of any use to an attacker, the code inserted into the buffer must be of a specific length, followed up by commands the attacker wants executed. So, the purpose of a buffer overflow may be either to make a mess, by shoving arbitrary data into various memory segments, or to accomplish a specific task, by pushing into the memory segment a carefully crafted set of data that will accomplish a specific task. This task could be to open a command shell with administrative privilege or execute malicious code.
Incorrect Answers:
B: Social engineering is when one person tricks another person into sharing confidential information, for example, by posing as someone authorized to have access to that information. This is a user issue; it is not a problem in software development.
C: Code injection is the exploitation of a computer bug that is caused by processing invalid data. Injection is used by an attacker to introduce (or "inject") code into a vulnerable computer program and change the course of execution. This is not one of the most common problems in software development today.
D: DOS applications are rare nowadays so unassembled reversible DOS instructions is not a prevalent problem today.
References:
Harris, Shon, All In One CISSP Exam Guide, 6th Edition, McGraw-Hill, New York, 2013, pp. 332, 337