https://homeostasis.scs.carleton.ca/wiki/api.php?action=feedcontributions&feedformat=atom&user=Dusanrozman 2026-05-02T07:46:04Z User contributions MediaWiki 1.42.1 https://homeostasis.scs.carleton.ca/wiki/index.php?title=SystemsSec_2016W_Lecture_2&diff=20509 2016-01-14T20:33:49Z

<p>Dusanrozman: </p> <hr /> <div>'''Topics &amp; Readings'''<br /> <br /> * Operating system security<br /> * Trusted computing<br /> <br /> '''Class Notes:''' <br /> <br /> Security mechanisms in a Unix system:<br /> <br /> * All processes have a user, group, and &quot;effective user&quot;. <br /> * users<br /> ** passwords<br /> ** users have file permissions<br /> ** User input may cause vulnerabilities therefore the OS must control the input in some way.<br /> <br /> *Networks<br /> ** IP tables: allows system admin to configure tables provided by Linux kernel firewall<br /> ** firewall used to protect system and restrict communication from untrusted sources.<br /> ** Just like not all programs can be trusted neither can all networks. <br /> ** Firewalls aren't only way to limit connections. Example, TCP wrappers: /etc/host.allow and /etc/host.deny<br /> <br /> <br /> * Disk encryption<br /> **Used to protect the information stored on disk from unauthorized users. <br /> * SSH (secure shell).<br /> ** Used to remotely log into a unix system. <br /> **SSH key is used to authenticate the user. <br /> * Notion of secure downloads on Ubuntu using &quot;apt-get&quot;. It's Utility used to install software packages and even upgrade the OS.<br /> <br /> <br /> <br /> '''Important Concepts:'''<br /> <br /> We briefly discussed the concept of what makes an OS secure.<br /> <br /> What to trust in an OS?<br /> * Kernel<br /> * all root priviledged code<br /> * daemons + set UID programs<br /> * file system permissions<br /> <br /> Applications don't interact with untrusted sources or are &quot;locked down&quot;.<br /> <br /> boot process<br /> <br /> The modern OS is a mess. That is with the amount of complexity (the millions of lines of code) in a modern OS it's difficult (close to impossible) to ensure security.<br /> <br /> Trusted Computing Base (TCB). TCB is synonymous with &quot;trust model&quot;. In other words it defines software and data that OS relies on to enforce it's security goals. Ideally, the TCB should be minimal.</div>

Dusanrozman https://homeostasis.scs.carleton.ca/wiki/index.php?title=SystemsSec_2016W_Lecture_2&diff=20508 2016-01-14T20:32:54Z

<p>Dusanrozman: Added notes for Jan 12th lecture. Work done by Dusan Rozman Xiusan Zhou</p> <hr /> <div>'''Topics &amp; Readings'''<br /> <br /> * Operating system security<br /> * Trusted computing<br /> <br /> '''Class Notes:''' <br /> <br /> Security mechanisms in a Unix system:<br /> <br /> * All processes have a user, group, and &quot;effective user&quot;. <br /> * users<br /> ** passwords<br /> ** users have file permissions<br /> ** User input may cause vulnerabilities therefore the OS must control the input in some way.<br /> <br /> *Networks<br /> ** IP tables: allows system admin to configure tables provided by Linux kernel firewall<br /> ** firewall used to protect system and restrict communication from untrusted sources.<br /> ** Just like not all programs can be trusted neither can all networks. <br /> ** Firewalls aren't only way to limit connections. Example, TCP wrappers: /etc/host.allow and /etc/host.deny<br /> <br /> <br /> * Disk encryption<br /> **Used to protect the information stored on disk from unauthorized users. <br /> * SSH (secure shell).<br /> ** Used to remotely log into a unix system. <br /> **SSH key is used to authenticate the user. <br /> * Notion of secure downloads on Ubuntu using &quot;apt-get&quot;. It's Utility used to install software packages and even upgrade the OS.<br /> <br /> <br /> <br /> '''Important Concepts:'''<br /> <br /> We briefly discussed the concept of what makes an OS secure.<br /> <br /> What to trust in an OS?<br /> * Kernel<br /> * all root priviledged code<br /> * daemons + set UID programs<br /> * file system permissions<br /> <br /> Applications don't interact with untrusted sources or are &quot;locked down&quot;<br /> boot process<br /> <br /> The modern OS is a mess. That is with the amount of complexity (the millions of lines of code) in a modern OS it's difficult (close to impossible) to ensure security.<br /> <br /> Trusted Computing Base (TCB). TCB is synonymous with &quot;trust model&quot;. In other words it defines software and data that OS relies on to enforce it's security goals. Ideally, the TCB should be minimal.</div>

Dusanrozman