Soma-notes - User contributions [en]

Computer Systems Security (Winter 2016)

2016-04-19T00:17:21Z

Keybra: /* Lectures and Exams */

==Course Outline==

[[Computer Systems Security: Winter 2016 Course Outline|Here]] is the course outline.

==Hacking Opportunities==

The [[SystemsSec 2016W Hacking Opportunities|Hacking Opportunities]] page lists potential hacking opportunities that you can attempt for your hacking journal. If you attempt but do not successfully accomplish one of them, be sure to document what you tried. As you learn more, you may come back to them and try again.

==Resources==

===Readings===

* For the first part of the course we will be reading selections from Trent Jaeger's [http://www.morganclaypool.com/doi/abs/10.2200/S00126ED1V01Y200808SPT001 Operating Systems Security] textbook. You can download the PDF [http://www.morganclaypool.com.proxy.library.carleton.ca/doi/abs/10.2200/S00126ED1V01Y200808SPT001 through Carleton's library]. In the reading assignments this text will be referred to as "Jaeger".
* An excellent but dated text on browser security is Michal Zalewski's [https://code.google.com/p/browsersec/wiki/Main Browser Security Handbook].

===Other Courses===

* Dan Boneh ran an excellent course at Stanford in Spring 2015 on [https://crypto.stanford.edu/cs155/ Computer and Network Security]. This course has many interesting readings that we will not be covering. Also, the assignments are very good sources for hacking opportunities.
* The assignments from the Winter 2015 run of COMP 4108 [https://ccsl.carleton.ca/~dmccarney/COMP4108/ are available]. They are a reasonable start for several hacking opportunities.

==Lectures and Exams==

<table style="width: 100%;" border="1" cellpadding="4" cellspacing="0">
<tr valign="top">
<th>
Date
</th>
<th>
Topic
</th>
<th>
Readings
</th>
</tr>
<tr>
<td>
Jan. 7

</td>
<td>
[[SystemsSec 2016W Lecture 1|Introduction]]

</td>
<td>Jaeger, Chapter 1 (Introduction)</td></tr>
<tr>
<td>
Jan. 12

</td>
<td>
[[SystemsSec 2016W Lecture 2|Access Control, Security Hacking 101]]

</td>
<td>Jaeger, Chapter 2 (Access Control Fundamentals)</td></tr>
<tr>
<td>
Jan. 14

</td>
<td>
[[SystemsSec 2016W Lecture 3|Multics, UNIX, and Windows]]

</td>
<td>Jaeger, Chapter 3 (Multics) and Chapter 4 (UNIX & Windows) </td></tr>
<tr>
<td>
Jan. 19

</td>
<td>
[[SystemsSec 2016W Lecture 4|Secure OSs, theory and practice]]

</td>
<td>Jaeger, Chapter 6 (Security Kernels) and Chapter 7 (Securing Commercial Operating Systems)</td></tr>
<tr>
<td>
Jan. 21

</td>
<td>
[[SystemsSec 2016W Lecture 5|LSM, SELinux, & Capabilities]]

</td>
<td>Jaeger, Chapter 9 (LSM & SELinux) and Chapter 10 (Secure Capability Systems)</td></tr>
<tr>
<td>
Jan. 26

</td>
<td>
[[SystemsSec 2016W Lecture 6|Secure Virtual Machines, Systems Assurance]]

</td>
<td>Jaeger, Chapter 11 (Secure Virtual Machine Systems) and Chapter 12 (System Assurance)</td></tr>
<tr>
<td>
Jan. 28

</td>
<td>
[[SystemsSec 2016W Lecture 7|Lecture 7]]

</td>
<td></td></tr>
<tr>
<td>
Feb. 2

</td>
<td>
[[SystemsSec 2016W Lecture 8|Lecture 8]]

</td>
<td></td></tr>
<tr>
<td>
Feb. 4

</td>
<td>
[[SystemsSec 2016W Lecture 9|Defensive Security Technologies / Hacking Opportunities]]

</td>
<td></td></tr>
<tr>
<td>
Feb. 9

</td>
<td>
[[SystemsSec 2016W Lecture 10|Security Research, Hashes, and Secure Protocols]]

</td>
<td></td></tr>
<tr>
<td>
Feb. 11

</td>
<td>
[[SystemsSec 2016W Lecture 11|Modeling a potential attack/ Midterm FAQ]]

</td>
<td></td></tr>
<tr>
<td>
Feb. 23

</td>
<td>
[[SystemsSec 2016W Lecture 12|Midterm Review]]

</td>
<td></td></tr>
<tr>
<td>
Feb. 25

</td>
<td>
Midterm (in class)

</td>
<td></td></tr>
<tr>
<td>
Mar. 1

</td>
<td>
[[SystemsSec 2016W Lecture 13|Buffer Overflow/Memory Corruption Attacks]]

</td>
<td>Aleph One (aka Elias Levy), [http://www.phrack.com/issues/49/14.html#article Smashing The Stack For Fun And Profit] (Phrack 49, 1996)</td></tr>
<tr>
<td>
Mar. 3

</td>
<td>
[[SystemsSec 2016W Lecture 14|Buffer Overflow/Memory Corruption Defenses]]

</td>
<td>
Wikipedia, [https://en.wikipedia.org/wiki/Buffer_overflow_protection Buffer Overflow Protection] 
Crispin Cowan et al., [https://www.usenix.org/legacy/publications/library/proceedings/sec98/cowan.html StackGuard: Automatic Adaptive Detection and Prevention of Buffer-Overflow Attacks] (USENIX Security, 1998)
</td>
</tr>
<tr>
<td>
Mar. 8

</td>
<td>
[[SystemsSec 2016W Lecture 15|Bypassing ASLR and Buffer Overflow Exploits using return-into-libc]]

</td>
<td>Hovav Shacham et al., [http://dx.doi.org/10.1145/1030083.1030124 On the effectiveness of address-space randomization] (ACM CCS, 2004) [http://dl.acm.org.proxy.library.carleton.ca/ft_gateway.cfm?id=1030124&ftid=285463&dwn=1&CFID=588127386&CFTOKEN=74533951 (proxy)] 
Hovav Shachem [http://dx.doi.org/10.1145/1315245.1315313 The geometry of innocent flesh on the bone: return-into-libc without function calls (on the x86)] (ACM CCS 2007) [http://dl.acm.org.proxy.library.carleton.ca/ft_gateway.cfm?id=1315313&ftid=476749&dwn=1&CFID=588127386&CFTOKEN=74533951 (proxy)]</td></tr>
<tr>
<td>
Mar. 10

</td>
<td>
[[SystemsSec 2016W Lecture 16|Network Firewalls]]

</td>
<td>Bellovin and Cheswick, [http://dx.doi.org/10.1109/35.312843 Network Firewalls] (IEEE Communications Magazine, 1994) [http://ieeexplore.ieee.org.proxy.library.carleton.ca/stamp/stamp.jsp?tp=&arnumber=312843 (proxy)]</td></tr>
<tr>
<td>
Mar. 15

</td>
<td>
[[SystemsSec 2016W Lecture 17|Lecture 17]]

</td>
<td>Dingledine, Mathewson, and Syverson, [https://www.usenix.org/legacy/events/sec04/tech/dingledine.html Tor: The Second-Generation Onion Router] (USENIX Security 2004) Albert Kwon et al., [https://www.usenix.org/conference/usenixsecurity15/technical-sessions/presentation/kwon Circuit Fingerprinting Attacks: Passive Deanonymization of Tor Hidden Services] (USENIX Security 2015) (background)[https://www.torproject.org/about/overview.html.en Tor: Overview]</td></tr>
<tr>
<td>
Mar. 17

</td>
<td>
[[SystemsSec 2016W Lecture 18|Lecture 18]]

</td>
<td>Blase Ur et al., [https://www.usenix.org/conference/usenixsecurity15/technical-sessions/presentation/ur Measuring Real-World Accuracies and Biases in Modeling Password Guessability] (USENIX Security 2015) 
Nikolaos Karapanos et al., [https://www.usenix.org/conference/usenixsecurity15/technical-sessions/presentation/karapanos Sound-Proof: Usable Two-Factor Authentication Based on Ambient Sound] (USENIX Security 2015)</td></tr>
<tr>
<td>
Mar. 22

</td>
<td>
[[SystemsSec 2016W Lecture 19|Lecture 19]]

</td>
<td>Giancarlo Pellegrino et al., [https://www.usenix.org/conference/usenixsecurity15/technical-sessions/presentation/pellegrino In the Compression Hornet’s Nest: A Security Study of Data Compression in Network Services] (USENIX Security 2015) Ramya Jayaram Masti et al., [https://www.usenix.org/conference/usenixsecurity15/technical-sessions/presentation/masti Thermal Covert Channels on Multi-core Platforms] (USENIX Security 2015)</td></tr>
<tr>
<td>
Mar. 24

</td>
<td>
[[SystemsSec 2016W Lecture 20|DDoS and Pinning]]

</td>
<td>Seyed K. Fayaz et al., [https://www.usenix.org/conference/usenixsecurity15/technical-sessions/presentation/fayaz Bohatei: Flexible and Elastic DDoS Defense] (USENIX Security 2015) Marten Oltrogge and Yasemin Acar, [https://www.usenix.org/conference/usenixsecurity15/technical-sessions/presentation/oltrogge To Pin or Not to Pin—Helping App Developers Bullet Proof Their TLS Connections] (USENIX Security 2015)</td></tr>
<tr>
<td>
Mar. 29

</td>
<td>
[[SystemsSec 2016W Lecture 21|Lecture 21]]

</td>
<td>David A. Ramos and Dawson Engler, [https://www.usenix.org/conference/usenixsecurity15/technical-sessions/presentation/ramos Under-Constrained Symbolic Execution: Correctness Checking for Real Code] (USENIX Security 2015) Nav Jagpal et al., [https://www.usenix.org/conference/usenixsecurity15/technical-sessions/presentation/jagpal Trends and Lessons from Three Years Fighting Malicious Extensions] (USENIX Security 2015)</td></tr>
<tr>
<td>
Mar. 31

</td>
<td>
[[SystemsSec 2016W Lecture 22|Cookie Integrity and XSSI]]

</td>
<td>Xiaofeng Zheng et al., [https://www.usenix.org/conference/usenixsecurity15/technical-sessions/presentation/zheng Cookies Lack Integrity: Real-World Implications] (USENIX Security 2015) Sebastian Lekies et al., [https://www.usenix.org/conference/usenixsecurity15/technical-sessions/presentation/lekies The Unexpected Dangers of Dynamic JavaScript] (USENIX Security 2015)</td></tr>
<tr>
<td>
Apr. 5

</td>
<td>
[[SystemsSec 2016W Lecture 23|Boxify and Android Permissions]]

</td>
<td>Michael Backes et al., [https://www.usenix.org/conference/usenixsecurity15/technical-sessions/presentation/backes Boxify: Full-fledged App Sandboxing for Stock Android] (USENIX Security 2015) Primal Wijesekera et al., [https://www.usenix.org/conference/usenixsecurity15/technical-sessions/presentation/wijesekera Android Permissions Remystified: A Field Study on Contextual Integrity] (USENIX Security 2015)</td></tr>
<tr>
<td>
April 7

</td>
<td>
[[SystemsSec 2016W Lecture 24|Final Exam Review]]

</td>
<td></td></tr>
<tr>
<td>
April 18, 10 AM-12 PM

</td>
<td>
Last-Minute Study Session in LA B146

</td>
<td></td></tr>
<tr>
<td>
April 19, 9 AM

</td>
<td>
Final Exam

</td>
<td></td></tr>
</table>

==Lecture Notes Guidelines==

Part of your participation mark is doing notes for at least one of the lectures. Here are the guidelines for those notes.

The class TA Borke (BorkeObadaObieh at cmail.carleton.ca) will be handling course notes. Please contact her to schedule your class to take notes.

Borke or Anil will set you up with an account on this wiki. You'll enter your initial draft notes here and then work with Borke to make sure they are of sufficient quality. This may require a few rounds of revisions; however, if you follow the guidelines below it shouldn't be too bad.

You should plan on organizing your notes as follows:
* Organize them in at least the following sections: Topics & Readings and Notes.
* The Topics & Readings section lists the main topics covered in the class, e.g. "buffer overflows". Please use an unordered bulleted list (using *'s in wiki markup). In this section also list readings relevant to the lecture that were mentioned in class.
* Put your notes in the Notes section.

Use (nested) lists if appropriate for the notes; however, please have some text that isn't bulleted. Please try to make the notes even if you did not attend lecture; however, you don't need to cover every small bit of information that was covered. In particular the notes do not need to include digressions into topics only tangentially related to the course. Complete sentences are welcome but not required.

==Security Reading Analysis Guidelines==

A security reading analysis is a detailed analysis of a security research paper. In it you analyze the key arguments of the paper and give your informed opinion.

Most security papers can be classified as attack or defense papers. You should analyze them differently.

For attack papers:
* What systems are vulnerable to the attack?
* What is the nature of the vulnerability?
* What is the the exploit? In particular, what is its technical core?
* How reproducible is the exploit?
* Are there likely to be many similar exploits, in the targeted system or other systems?
* How difficult will it be mitigate/fix the vulnerability in targeted systems?

For defense papers:
* What is the security problem the paper addresses? In what kind of threat model(s) does the problem exist?
* How significant is the problem? Specifically, to what degree do existing solutions not work sufficiently well?
* What is the defense? How does it work?
* To what degree will the defense potentially solve the targeted security problem? In particular, how difficult will it be for attackers to adapt to this defense?
* What are the challenges facing deployment of the defense? Are they likely to be overcome?

For both kinds of papers, you should give your reaction by addressing questions like the following:
* Did you like the paper?
* Was it easy to understand, or was it hard to read?
* Did you learn much from the paper?
* How surprised were you by the result?

Your analysis should not cover the above questions separately (this would tend to make for a very wordy analysis); instead, use these questions as a guide in writing a short essay (1-2 pages) on the paper in question.

Each analysis will be graded out of 10 as follows:
* U: 3 for demonstrating understanding of the content (preferably without summarizing)
* T: 3 for technical analysis (does it work)
* C: 3 for contextual analysis (does it matter)
* V: 1 for your viewpoint

SystemsSec 2016W Lecture 16

2016-04-17T00:36:38Z

Keybra: A summary/explanation of the Network Firewalls paper and its concepts covered.

== '''Paper: Network Firewalls''' ==

'''The Security of Networked Computers'''

* The security of networked computers rests on a good system admin, reliable vendor software, and an educated user community.

* Three points to consider on the security of networked computers:
** There are many points to defend on a networked computer: the mailer, the networked file system, the database servers, and even just the login prompt. These all must be secured.
** There are many points of attack, because the computer is networked (internet) it can be attacked remotely.
** Not all machines can be as secure as the system admin would like. Some users may connect to the network with weakly secured machines that compromise the network (mobile phone).

* A firewall is one answer to these three points. Disconnection from the network entirely is another.

* It is up to the individual on which solution they choose. They must balance the cost of system failure with the benefits provided by a network. Usually the benefits outweigh the costs.
* Because programs represent potential security holes due to bugs, the amount of programs running on machines should be minimal to limit potential points of attack. Any programs not in use should be disabled.

'''The Definition of a Firewall'''
* A firewall can be defined as a collection of components placed between two networks that collectively have the following properties:
** All traffic from inside to outside, and vice-versa, must pass through the firewall.
** Only authorized traffic, as defined by the local security policy, will be allowed to pass.
** The firewall itself is immune to penetration.
* Failure in one of these properties simply means the firewall is a bad one.

'''On Gateways'''
* A gateway is a dedicated machine that runs a firewall.
* Using a gateway machine for a firewall gives certain benefits. Other computers on the network should not trust the gateway automatically. This means that if the gateway containing the firewall falls, no other machine falls automatically.
* A firewall usually has two filters to block transmissions of a certain type. The outside filter can be used to protect the gateway from attack, while the inside filter can be used to guard against the consequences of a compromised outside filter.

'''Firewalls: Packet Filtering, Circuit Gateways, Application Gateways'''
* Firewalls are classified into three main categories: packet filtering, circuit gateways, and application gateways.
* Packet filtering gateways drop packets based on either their source, their destination, or their service (port number).
* Circuit gateways are relays that allow a machine to connect to its TCP port to communicate with some destination on the other side of the gateway.
* Application gateways are like packet filtering gateways but are specific to a single app and so have the benefit of targeting the specific flaws in each app.

* Packet filtering gateways can have problems with FTP, DNS. Due to the connectionless protocol of UDP, it cannot work with it.
* Setting port rules on a packet filtering gateway leaves no room for error.

* Application gateways require the use of specialized user interfaces for services provided.
* This has the downside that mostly popular services will support the use of application gateways, while newer lesser known services might not. This makes it hard to adopt newer technologies.

* Circuit gateways offer detailed control over the flow of information between two points.
* For example, connection to a circuit gateway can control who gets access to the printer in the boss' office. Certain machines can be disallowed connection to use the printer in the boss' office.

* It is often a combined use of all these types of firewalls that provides the best security.

'''On Tunneling'''
* One of the most dangerous methods of bypassing a firewall is the use of tunnels. A tunnel is the encapsulation of a message from one protocol to another, the second protocol is used to traverse the network, and finally at the destination of the message the second protocol is stripped and the original message is read as intended.
* If users are given the ability to send packets, and therefore to create tunnels from inside to an outside source, then they can bypass the firewall and send any message they want.
* Solution? The process of making a tunnel means that the user computer must bypass the dedicated gateway; to do so it must be known to the external router. The external router should only know the dedicated gateway, not the user computer, so if an application or circuit gateway is being used this can easily be detected. The user computer in violation of network security can be identified, and the individual at fault can be handled (it becomes an issue of management).

* Consider that firewalls are especially useful for keeping potential attackers out when they are attacking from outside. They are not all that good at keeping those "out" who are already "in" (the building). This means employees that do not respect security of the network are not necessarily the responsibility of the firewall (out of its scope of defense). Again, this is an issue of internal management.