Lynis is an auditing and hardening tool for Unix derivatives like Linux/BSD/Solaris. It scans systems to detect software and security issues. Besides security-related information, it will also scan for general system information, installed packages, and possible configuration mistakes. The software is aimed at assisting automated auditing, software patch management, and vulnerability and malware scanning of Unix-based systems.
Kernel Security Checker is a useful tool to locate attackers residing within a system by employing a direct analysis of the kernel through /dev/kmem and bypassing the hiding techniques of the intruder (kernel static recompilation or use of LKMs). It can find the modified syscalls from userspace, detect the promiscuous interfaces, and find the modifications applied to a protocol.
net-status-monitor is a simple console script to test whether Internet connectivity is working. If it is, the script tells you the external IP address (in case your dynamic DNS provider is down). If not, it tries to find the point where the connectivity fails. The output is quite simple, so you can put it on your grandmother's PC. "Just tell me what the read line says" should give you enough information.
Nagstamon is a Nagios status monitor with a UI that resides in the systray or as a floating statusbar on your desktop. It informs you in realtime about the status of your Nagios, Icinga, Opsview, Ninja, Check_MK/Multisite, Centreon, or Thruk-monitored network. It alerts you with sound and visual notification. Failed hosts and services are easy to connect with by SSH, RDP, and VNC. Custom actions can be run on certain events. It works best with GNOME, but also with KDE, Mac OS X, and Windows.
Zoom is a low-overhead graphical and command line profiler for Linux. Profiles are system-wide, precise down to the instruction level, and capture complete backtraces of C/C++/ObjC/Fortran/Assembly code. This lets you see exactly where time was spent, what code was running (user or kernel), and how that code was called. Drill down into a specific symbol, and Zoom shows source and assembly annotated with general and processor-specific tuning advice. It saves profiles as a single, self-contained session file that can be emailed or attached to bug reports. This lets you share what you find with colleagues or archive it for later review. Zoom also supports remote network profiling and scripting, making it ideal for embedded or server systems and automated workflows.
FTPL (FakeTime Preload Library, aka libfaketime) intercepts various system library calls and tricks programs of your choice into seeing a faked system time without having to change the time system-wide. This can be used for running legacy software with Y2K bugs, testing software for year-2038 compliance, debugging time-related issues such as expired SSL certificates, and using software that ceases to run outside a certain time frame. The faked time can be specified either absolutely or relative to the real current time, and optionally also affects file timestamps. The faked clock continues to run, but can optionally be frozen, slowed down, or made faster. A wrapper script "faketime" simplifies the usage, similar to tools such as fakechroot.
SystemRescueCd is a Linux system available from a bootable CDROM that provides an easy way to perform administrative tasks on your computer, such as creating and editing the partitions of the hard disk or backing up data. It contains a lot of system utilities (such as parted, partimage, and fstools), and basic programs (such as editors, midnight commander, and network tools). It also includes GParted, a Partition Magic clone that makes editing partitions easy with its graphical user interface. This CDROM aims to be very easy to use and accessible to everybody, and it also provides advanced personalization features.
ProcMeter3 is a program for monitoring the system status and other information and displaying it in a series of graphs or as text. Most of the information comes from the /proc filesystem (cpu usage, load average , processes information, memory usage, network traffic, interrupts etc.). Other information is available for other sources (date, time, email status, log file length, disk status etc.). The program is modular and highly configurable.