Chapter 1 begins with some anecdotes about security issues to impress the student with the need for information system security. We might presume that someone who signs up for this class has the idea that such needs exist already. The author presents examples of several ways a computer system might be attacked, compromised, or otherwise damaged:
Some types of attacks are hard to defend against, according to the chart on page 7. Reasons why:
The text turns to a series of definitions that may not seem to apply to all cases. That may be true, but they are general definitions, a starting point to consider what we are working with and working toward.
The author discusses the idea that a security program cannot guarantee freedom from attack. The goal is to eliminate or minimize damage from attacks that take place. He provides a justification for providing such protection: to maintain the value of information. He says that there are three aspects of information that are typically protected:
The rather long formal definition of information security that appears on page 10 adds three more concepts: products, people, and procedures are what provide the protection. Products refers to hardware and software such as firewall devices and authentication software. People would primarily be whoever installs and uses security products. Procedures means plans, policies, and actual steps carried out by those who use information, as well as by those who protect it. I think it is a bit of a reach to have the formal definition include three attributes of information, three ways it is used in a system, and three entities that protect it. This is likely one of those certification question points that we just have to accept as worded the way it is worded, and we aren't allowed to improve it.
The text moves on to discuss more vocabulary, illustrated by a story about a woman who wants to put a new stereo system in her car. The story is useful, but not necessary to understand the terms.
The next section of the text lists several goals of information security that could also be considered as benefits of it.
The text discusses some categories used to classify attackers:
The text lists five steps that an attacker may follow in preparing for and carrying out a computer system attack:
Consider that not all attackers will follow all five of these steps. Some would damage a system without making a back door for later, some would explore a system but never damage it, and others might steal data to make public what the data owners would rather be secret.
I am getting the feeling that the author of this text is obsessed with symmetry. He gave us five steps in an attack scenario, so he also gives us five defenses against attacks.
The text moves on to discuss types of jobs commonly associated with information system security. It makes a distinction between jobs about Information Security (as it has been discussing) and jobs about Information Assurance, which would also have to do with disaster recovery, business continuity, and major planning for the business enterprise.
Within Information Security, the text says that jobs typically relate to administrative, planning, and policy roles, or they relate to technical functions like installation, operation, and maintenance.
The text offers a table on page 23 which you should study to be aware of the job functions for four job titles: Chief Information Security Officer, Security Manager, Security Administrator, and Security Technician. (This is their order in terms of descending levels of authority.)
The content section of the chapter ends with a few words about the CompTIA Security+ certification, which is meant to be a vendor neutral certification of knowledge about the subject area. Links are provided on the menu page for this course to the CompTIA web site, and others, so you can get up to date information about testing for this certification. The certification test for Security+ covers six domains (areas of knowledge):
Chapter 2 is titled System Threats and Risks. It begins with two unrelated articles, one about using spam detection algorithms to detect HIV activity, and the other about users being a weak point in Information Security schemes. Both raise interesting points, but they seem unrelated to the focus of the chapter.
In the previous chapter, spam was mentioned as a major loss point for productivity. This seems less likely now. Gmail, for example, is very good at removing spam from a regular mail folder, and it does not take long to examine and empty the spam folder periodically. It seems more likely that virus laden spam would be the greater problem. The text says that Postini, an email and web security service, estimated that two thirds of email is unsolicited. That does not seem extreme to me. Of course, most of it unsolicited, how often do you solicit email? (Note: Google bought Postini in 2007.)
The chapter begins its discussion of software base attacks on page 41. The term malware is introduced, meaning any software that does something harmful to a system. The text breaks malware in to three types, based on which of three objectives the malware follows: infecting a system, concealing its actions, or bringing profit from its actions.
Infecting software is divided into viruses and worms. A virus typically requires a carrier to infect a system, like an email, an instant message, or a program that the user runs. A virus typically has two tasks: replicate and damage. Some viruses have historically been rather benign, just displaying a message to the user. The ones that cause damage to a system are categorized by the method they use or the damage they cause:
Virus protection programs typically recognize viruses by signatures, the way they look. This recognition method is complicated by metamorphic viruses that change the way they look over time, and polymorphic viruses that change their signature and their encryption methods.
Worms are described on page 44. The text tells us a major difference between worms and viruses: once it is started, a worm can replicate itself across connected computer systems by itself. It does not need a carrier. A worm can attack any running computer that is connected to a network that an infected computer is on: it does not require cooperation from the user. Worms are more dangerous due to their self driven nature. Once a worm is detected in a system, each device on the network must be scanned for it, cleaned if necessary, and prevented from accessing the network until this is done.
The text lists four types of malware that are first concerned with remaining hidden from the user and from security personnel: trojan horses, rootkits, logic bombs (not a terribly accurate name), and privilege escalators.
Trojan horse programs are named for the myth of a wooden horse that was used to smuggle Greek soldiers inside the walls of Troy. A program of this sort has two aspects: what we are told it does, and what it actually does. In some cases, Trojans may do what they say, but they also have a hidden malicious purpose which is what puts them in this category. A classic ploy used by Trojans is to pretend not to be a program at all. The text gives an example of a file that has a .exe extension, but the characters .docx occur in the name immediately before it. If a Windows computer is using the default (idiotic!) configuration, the actual .exe extension will be hidden from the user, and the user may think it is only a Word document.
Students should become familiar with the methods to turn off "Hide extensions for known file types" in common versions of Windows.
The text continues to discuss rootkits. At first, the rootkit sounds like a resident virus that replaces operating system files with its own. There are similarities, but one difference is that a rootkit is much more extensive, and another is that the rootkit obtains elevated privileges to carry out its stealth actions. The resident virus may replace one program on the computer, which will then do some harm to the system. The rootkit opens a door for lots of malware. How?
Have you ever seen a movie about a robbery in which the robbers send false information to security staff (like a video loop) that shows all is well, while the robbers proceed to steal whatever they want? That's kind of what a rootkit does. The rootkit assumes the role of a trustworthy part of the operating system. It will stand between the user and security software on one side, and other malware doing whatever it wants on the other.
The intention of the rootkit programmer may not be malicious. The text discusses the example of Sony, who in 2005 installed a rootkit installer on their audio CDs which had the goal of preventing computer users from copying those CDs. Their intent was not malicious, but it changed a PC without the user's consent, and it made the PC vulnerable to security exploits. The first is just wrong, and the second is worse. As the saying goes, the road to hell is paved with good intentions.
Detection and removal of a rootkit can be difficult, but it is worth trying before following the text's scenario of formatting the hard drive and starting over. The Sophos company, for example, has a free download that is supposed to be good at finding and removing these problems. Here is another one from Kaspersky. Students should do an internet search for tools from the vendor of their choice.
A logic bomb is not a bomb. It is malware that waits for a logical condition to occur before it executes its mission. A classic case was the Michelangelo virus that only executed on the birthday of Michelangelo Buonarroti (which, as everyone knows, is March 6th). Other examples are given in the text. Some act like "dead man switches", where the malware engages if it is not regularly reset, or if a person's ID is removed from a network. A logic bomb can be hidden in a much larger program, making it difficult to find.
Privilege escalation is a technique, not a type. The technique is commonly use by system administrators. They log in to networks with an ID that has normal privileges on the system, but they execute administrative tasks with an ID that has elevated privileges. Of course, these are authorized users who are supposed to do such things. When malware does this, it may do it in one of two ways. It may use an exploit to escalate its own privileges, or it may access the privileges of another account which are greater than its own.
Malware for Profit
The text discusses some major and minor types in this category. The first is spam, which was discussed briefly in chapter 1. Note that in chapter 1 the author told us that Postini (now Google) said that "over two-thirds of daily email messages are unsolicited". In this chapter, the author quotes the same source as saying one out of twelve emails is spam. Is this a contradiction?
As I noted above, the fact that an email is unsolicited is not very meaningful. The fact that it is an unsolicited sales pitch may be more meaningful. The fact that the spam sender (spammer) has no clue who you are or whether you will buy their product seems to be the most meaningful qualifier. The definition used for the word "spam" might be any of these or something else, as far as we know about the statistics we are given.
Spam that is sent for profit is sent to as many addresses as possible to maximize the potential of getting a sale. The text gives two scenarios that are meant to be examples of gauging how much it costs to be a spammer. They are not the only possibilities. The point is that the cost to the spammer is minimal (until they are arrested) and the returns are very large.
The text discusses some techniques to make a spam email that will get by spam filters in many security products:
Spyware is described on page 51. It is defined as software that violates a user's security. More informatively, the text says that spyware typically has one of three missions: advertising, collection of personal information, or changing configuration settings. The text proposes that if other software did what spyware does with the user's permission, that software would not be spyware. So the issue is not what it does, as much as the fact that it is done in secret.
The chart on page 52 lists effects that spyware can have on a computer. Several of these items seem to be less related to spying than to leading the user to particular products and resources. As such, I would consider "spyware" to be an inappropriate label for the category. A better label is the subcategory the text talks about next, adware. As its name suggests, adware is concerned with presenting advertisements to the computer user. I will point out that the text makes this a subcategory of spyware, but I disagree with the logic of making it one.
Another subcategory of spyware is more appropriate. Keyloggers can be implemented through hardware or software. The idea is that the program (or device) captures every key press the user makes, which can be analyzed later for by someone who reads the key log. Obviously, capturing IDs and passwords would be one use of such a product. Keeping a log of all activity on a computer would be another. Some viruses contain a key logging function which sends its log to the virus originator.
A newer wrinkle in malware is the botnet. This has been around for a while, but it is a refinement and step back from the others at the same time. A botnet is a network of computers that have been infected, turned into robots (aka zombies), that can be used for any of several kinds of attacks listed on page 54. The refinement is the creation of a network of infected machines on one mission. The step back is the brute force aspect of the attacks. The attacker (the bot herder) does not depend on finesse or subtlety, he uses more points of attack to meet his goal.
Key loggers can be implemented through hardware, but there are several other hardware attack vectors you should know about.
All PCs have BIOS chips or chip sets. They control the computer hardware at a very basic level and are still important to computer systems. As the text explains, once upon a time (let's say the 1970s), BIOS chips were read only and had to be replaced if you were going to update them. The text reviews the history of BIOS chips becoming flashable (rewritable). A virus that overwrites the BIOS and the Master Boot Record of a computer has the potential to make the computer unusable until the BIOS is physically replaced. Other viruses will attack the BIOS and coopt it with malware or a rootkit. For these reasons, the text recommends setting the BIOS chip to be write protected.
The phrase USB device can mean any device that attaches through a USB port, but the text is concerned with those that contain memory chips or hard drives that could contain viruses. This is not to say that other devices can't be modified to become exploit devices. At the 2011 DEFCON conference, a pair of hackers demonstrated that they could rig a mouse to hold a USB stick that contained malware that could compromise a network. In a sense, this is just another instance of a hack involving a memory stick, but it is more in that most people can be made aware of the dangers of flash memory, and few would generalize that awareness to other devices that they would normally consider safe. The text lists three methods to disable USB devices:
Of the three, only the third is practical. How many of you connect a mouse or a printer by any means other than a USB port? A good security program can be configured to scan devices as they are attached or used to minimize this risk.
The text moves on to discuss two related systems: Network Attached Storage (NAS) and Storage Area Network (SAN). One version of a SAN is illustrated on page 57, showing a workstations and servers on a LAN (Local Area Network). The servers are also connected to a SAN, essentially a network of other servers dedicated to file storage. These servers will use different network protocols than devices on the same LAN.
The distinction between the two systems is that NAS devices can be exploited and protected in the same way as hard drives on any other computer on your LAN. The text warns that using NAS devices on a network without high bandwidth connections to the NAS device can produce a service bottleneck.
The text turns to cell phones. The text describes how a cell system works: phones connect to cell towers (base stations) which connect to an MTSO (mobile telecommunications switching office), which connects to the wired telecommunications network. Cell phones are low power devices, so they have to switch from one base station to another as they move from the operational range of one to the next. That means that a cell phone in motion is constantly changing base stations, but it also means that each base station can use the same radio frequencies for the phones inside its cell. A few ideas about cell phone attacks are listed on page 59. None are very detailed.
Virtualized System Attacks
On page 59 the text defines virtualization as a functional presentation of computer resources, regardless of their location. The text offers the example of a set of storage devices that could be treated as one. Another example is running a version of a server operating system as a virtual machine (VM), a shell, inside the the memory of a server or workstation. We could have a workstation running Windows 7 that runs a virtual machine for Windows Server 2010. In this case the Windows 7 is the host system, and the Windows Server 2010 VM is a guest system. The chart on page 60 lists four variations on virtualization;
This set of definitions left me wanting more. Try this short article on wikipedia.
The text explains that a selling point for running several virtual machines on a single server box is reduction in power and cooling costs over having to power and cool that many separate boxes. Virtual systems can be tested for the effect of patches and updates without having to sacrifice an entire computer to the test. Rolling back from a bad change is often quicker on a virtual machine than on regular hardware.
To a system attacker, virtualization also reduces costs: virtual machines mean being able to use tools for multiple operating systems on one computer. System defenders can use virtual machines to test attacks and defenses, using a virtual network, further reducing test lab costs.
After some repetition, the text discusses other advantages to using virtual machines. Live migration of virtual machines can greatly reduce down time, The virtual machine is essentially "saved" in a current state, reloaded on a separate host, then the original host can be taken down for maintenance without the down time that would normally occur. The same technique can be used to move the virtual machine to more or less powerful equipment, to balance loads as user demands increase and decrease,
A problem described in the text regarding these practices comes from security software not always working well with virtual machines, and security hardware sometimes only protecting one machine at a time. Also, a virtual machine may have no hardware protection at all between it and an attack from another virtual machine in the same host or same virtual network. Perhaps an obvious place to apply security is to the hypervisor (described on page 62), which is software that manages virtual machines. Whether it is an add on for the hypervisor or a patch for the program itself, the effect would be similar. It seems equally obvious that if it is not possible to run your security software as a virtual service/machine or to modify the hypervisor, then security measures should be installed on each virtual machine as you would any other piece of hardware.