CIS 527

Services, Software & Security

Services

• Programs that run in the background on an operating system
• Performs many important functions automatically
• Consumes system resources

Startup Types

• Automatic - Starts at system boot
• Automatic (Delayed) - Starts shortly after system boot
• Manual - Starts only when needed
• Disabled - Will not start/run at all

Windows 10 Pseudo Accounts

• LocalSystem - system-level tasks & services
• LocalService - fewer rights than LocalSystem
• NetworkService - fewer rights than LocalService, but allows network access

Recovery Options

• Take No Action
• Restart the Service
• Run a Program
• Restart the Computer

Important Services

• Computer Browser - Network file sharing
• DHCP Client & DNS Client - Network addressing
• Microsoft Antimalware Service
• Performance Logs & Alerts
• Print Spooler
• Windows Update

Service Host Process

• svchost.exe
• Process that runs a number of system services
• Helps conserve system resources (1 process instead of many)
• Targeted by malware & viruses

Linux Services - daemons

• Daemons run as background processes in Linux
• Usually started by the init process at boot
• Managed by systemd on most distros
• Process names typically end in 'd'

Starting Linux Services - init

• The init process is loaded first
• It then loads the services for a particular runlevel
• See /etc/init.d/ and /etc/rc*.d/ directories

Starting Linux Services - Upstart

• Ubuntu 14.04
• Allows services to be started based on events
• "greedy" loading
• Can monitor and restart services
• Very similar to Windows Service Management

Starting Linux Services - Systemd

• Implemented in Ubuntu 15.04+
• "lazy" loading
• Can monitor and restart services
• Very similar to Windows Service Management

Linux Daemon Commands

• init
  • sudo /etc/init.d/apache2 start
  • start, stop, reload, restart, status
• Upstart
  • sudo service ufw start
  • start, stop, status

Linux Daemon Commands

• Systemd
  • sudo systemctl start ufw
  • start, stop, reload, status

Processes

• Computer program being executed
• May contain multiple threads of execution
• Consumes resources such as memory & processing time

Task Manager

Process Information

• PID - Process ID
• Memory Usage - Process ID
• Description - Process ID
• Image Path - Process ID
• Command Line - Process ID
• Ports - Network Socket Ports

Ubuntu System Monitor

Ubuntu Processes - top

Windows Software Architecture

• Executable Image (.EXE)
• Dynamic Link Library (.DLL)
• Initialization File (.INI)
• Registry Keys
• Drivers
• Services

Executable Image (.EXE)

• Contains the actual executable code for an application
• May also contain resources, graphics, fonts, etc.
• Based on the old Unix COFF (Common Object File Format)

Dynamic Link Library (.DLL)

• Shared library files used by programs
• Uses same format as .EXE file
• Programs can access same .DLL files simultaneously

Initialization File (.INI)

• Informal standard for configuration files
• Used extensively in Windows up to Windows ME for system & software settings
• Structured text files

Registry Keys

• Structured data storage for system settings
• Key <-> Value pairs
• Faster loading of settings
• Allows multiple users to use a system simultaneously

Windows Software Install Process

• Extract/expand files
• Place files in location
• Create registry keys
• Install drivers/services
• Create user data files
• Create shortcuts

Ubuntu Software Architecture

• Binary Files
• Shared Object Files (.SO)
• Library Files
• Settings Files
• Documentation Files
• Upstart/Systemd/init scripts

Binary Files

• Contains the executable code for the application
• Uses the ELF (Executable and Linkable Format)
• Commonly used in many Unix-like systems
• Usually stored in /bin folder

Shared Object & Library Files

• Shared information or code used by multiple programs
• Install once, use everywhere
• May have to store multiple versions for different programs
• Usually stored in /usr/lib

Settings Files

• Configuration files used by programs
• Text based, similar to .INI files
• Usually stored in /etc for system-wide settings or in a hidden folder in ~/ (like ~/.thunderbird)

Documentation Files

• Stores information about the software
• Responds to 'man' command on terminal
• Usually stored in /usr/share folder

Ubuntu Package Management

• Most software installed via "packages"
• Packages are provided from a repository
• Programs such as Synaptic or apt can install packages
• Programs can also be installed from source

Ubuntu Software Commands

• apt-get install (package)
• apt-get update
• apt-get upgrade
• apt-get dist-upgrade
• auto-apt run (command)
• dpkg-reconfigure (package)

Ubuntu Software Install Process

• Extract/expand files
• Place files in location
• Create user data files (usually on first run)
• Create startup scripts

System Security

1. Install system updates
2. Install antivirus software
3. Configure firewall
4. Set up users and passwords

Principle of Least Privilege (PoLP)

• Only allow access to programs and data to users who have a legitimate need
• Do work on an account with limited permissions
• Use an administrator account only when needed
• Protect files restrictively

Assignments

• Lab 1 - Building Secure Workstations: Due Monday Jan 30th by 10:30 AM