Krishna Computer networks that are currently connected to the Internet are vulnerable to a variety of exploits that can compromise their intended operations. Systems can be subject to Denial of Service Attacks that prevents other computers from connecting to them for their provided service (e.g. web server) or prevent them from connecting to other computers on … Read more
It is possible that email and browser-based viruses, Trojans and worms are the source of the myth that Windows is attacked more often than Linux. Clearly there are more desktop installations of Windows than Linux. It is certainly possible, if not probable, that Windows desktop software is attacked more often because Windows dominates the desktop. … Read more
HOW TO SET UP A FIREWALL UNDER LINUX? To configure a Linux firewall, you will likely use the latest implementation of firewalling, called IPTables. IPTables is a packet filter for kernels 2.4 and above. It is a tremendous improvement over IPChains and provides enhanced features such as stateful packet filtering, Network Address Translation, MAC Address … Read more
/etc/passwd is a text file that contains the attributes of (i.e., basic information about) each user or account on a computer running Linux or another Unix-like operating system. DESIGN The permissions for /etc/passwd are by default set so that it is world readable, that is, so that it can be read by any user on … Read more
SHADOW FILE In Unix-like operating systems, /etc/shadow is used to increase the security level of passwords by restricting all but highly privileged users’ access to hashed password data. Typically, that data is kept in files owned by and accessible only by the super user. DESIGN Systems administrators can reduce the likelihood of brute force attacks … Read more
LINUX DIRECTORY STRUCTURE (FILE SYSTEM STRUCTURE) EXPLAINED WITH EXAMPLES Figure: Linux file system 1. / – Root Every single file and directory starts from the root directory. Only root user has write privilege under this directory. Please note that /root is root user‘s home directory, which is not same as /. 2. /bin – User … Read more
LINUX/UNIX has three most important parts. They are Kernel, Shell and File System Figure: Layers of Linux Kernel Kernel is the heart of the operating system. It is the low level core of the System that is the interface between applications and H/W. Functions Manage Memory, I/O devices, allocates the time between user and process,inter … Read more
Even if it were possible to lock a system down air tight, it is not always practical to invest the time and effort required to do so. The best thing to do is to first determine your risk, and then secure accordingly. Risk= (threat*vulnerability*impact) Threat: What is the probability of you coming under attack? Who … Read more
Linux can give you: 1. A modern, very stable, multi-user, multitasking environment on your inexpensive PC hardware, at no (or almost no) monetary cost for the software. Linux is a rich and powerful platform don’t think of it as a “poor people” operating system. Out-of-box Linux has as much capability as MS Windows NT with … Read more
INTRODUCTION It is a commonly held principle in many areas of business that if you can‘t measure something quantitatively, it will be difficult to raise the quality objectively. The applicability of this statement to the world of IT security is clear. Without having some form of metrics in place, it is tough, if not impossible, … Read more