Security and ethics ROLE OF OPERATING SYSTEM IN SECURITYSystem SurvivabilitySystem survivability - is defined as “the capability of a system to fulfill its mission, in atimely manner, in the presence of attacks, failures, or accidents (Linger, 2002).”• The term system refers to any system. It’s used here in the broadest possible sense from laptop to distributed system to supercomputer.• A mission is a very high-level set of requirements or goals.• In a timely manner refers to system response time, a critical factor for most systems.• The terms attack, failure, and accident refer to any potentially damaging incident, regardless of the cause, whether intentional or not.

backup and recovery, policies in place and performing other archiving techniques - are standard operating procedure for most computing systems.

Backups, with one set stored off-site, are also crucial to disaster recovery. The disaster could come from anywhere. Here are just a few of the threats:

• water from a fire upstairs • fire from an electrical connection • malfunctioning server • corrupted archival media • intrusion from unauthorized users

Security BreachesUnintentional IntrusionsAn unintentional attack - is defined as any

breach of security or modification of data that was not the result of a planned intrusion.

accidental incomplete modification of data - When non-synchronized processes access data records and modify some of a record’s fields,

An example was given in Chapter 5 when we discussed the topic of a race in a database with two processes working on the same student record and writing different versions of it to the database.

Intentional AttacksIntentional unauthorized access includes denial of

service attacks, browsing, wiretapping, repeated trials, trapdoors, and trash collection.

Intentional Unauthorized AccessDenial of service (DoS) attacks - are

synchronized attempts to deny service to authorized users by causing a computer (usually a Web server) to perform a task (often an unproductive task) over and over, thereby making the system unavailable to perform the work it is designed to do.

Browsing is when unauthorized users gain the capability to search through storage, directories, or files for information they aren’t privileged to read.

Wiretapping - is nothing new. Just as telephone lines can be tapped, so can most data communication lines.

There are two reasons for passive tapping:to copy data while bypassing any authorization

procedures and to collect specific information (such as passwords)

that will permit the tapper to enter the system at a later date.

Active wiretapping is when the data being sent is modifiedTwo methods of active wiretapping are:“between lines transmission” and “piggyback entry.”Between lines doesn’t alter the messages sent by the

legitimate user, but it inserts additional messages into the communication line while the legitimate user is pausing.

Piggyback entry intercepts and modifies the original messages.

Repeated trials - describes the method used to enter systems by guessing authentic passwords.

Average time required for a human and computer to guess passwords up to 10 alphabetic characters (A–Z) using brute force.

Trapdoors - including backdoor passwords, are defined as unspecified and undocumented entry points to the system.

Trash collection - also known as dumpster diving - is an evening pastime for those who enjoy perusing anything and everything thrown out by system users—the discarded

disks, CDs, faxes, printer ribbons, as well as printouts of source code, programs, memory dumps, and notes.

VirusesA virus - is defined as a small program written to

alter the way a computer operates, without the permission or knowledge of the user.

A virus must meet two criteria:

• It must be self-executing. Often, this means placing its own code in the path of another program.

• It must be self-replicating. Usually, this is accomplished by copying itself from infected files to clean files as shown in Figure 11.2. Viruses can infect desktop computers and network servers alike and spread each time the host file is executed.

A file infector virus attacks a clean file (a) by attaching a small program to it (b), which executes every time the infected file runs.

WormsA worm - is a memory-resident program

that copies itself from one system to the next without requiring the aid of an infected program file.

TrojansA Trojan - (originally called a Trojan Horse)

is a destructive program that’s disguised as a legitimate or harmless program that sometimes carries within itself the means to allow the program’s creator to secretly access the user’s system.

There are five recognized types of viruses:File infector virus - Infects files on the computer,

normally executable files such as .exe and .com files commonly found on Microsoft operating systems. These viruses commonly become resident in memory and then infect any clean executable program that runs on that computer.

Boot sector virus - Infects the boot record, the system area of a floppy disk or hard drive. These viruses activate whenever the user starts up (powers on) the computer. Most boot sector viruses were written for MS-DOS, but other operating systems are potential targets.

Master boot record virus - Infects the boot record of a disk, saving a legitimate copy of the master boot record in a different location on the volume.

Multipartite virus - Infects both the boot record and program files, making them especially difficult to repair. Successful removal requires that all instances of the virus be removed at once—on the boot records as well as all instances of files infected with the virus. Should any instance of the infection remain, the virus will infect the system again.

Macro virus - Infects data files (such as word processing documents, spreadsheets, etc.), though newer versions now infect other program files as well. Computer users are advised to disable the automatic execution of macros on files they don’t completely trust. macro virus - works by attaching itself to the template which, in turn, is attached to word processing documents.

Intruders have been known to capture user passwords by using a Trojan to replace the standard login program on the computer with an identical fake login that captures keystrokes. Once it’s installed, it works like this:

1. The user sees a login prompt and types in the user ID.2. The user sees a password prompt and types in the

password.3. The rogue program records both the user ID and password

and sends a typical login failure message to the user. Then the program stops running and returns control to the legitimate program.

4. Now, the user sees the legitimate login prompt and retypes the user ID.

5. The user sees the legitimate password prompt and retypes the password.

6. Finally, the user gains access to the system, unaware that the rogue program has stored the first attempt and recorded the user ID and password.

BombsA logic bomb - is a destructive program

with a fuse—a certain triggering event (such as a certain keystroke or connection with the Internet).

A time bomb - is similar to a logic bomb but is triggered by a specific time, such as a day of the year.

Blended ThreatsA blended threat - combines into one

program the characteristics of other attacks, including a virus, a worm, a trojan, spyware, key loggers, and other malicious code.

System protectionAntivirus software - can be purchased to protect

systems from attack by malicious software.The level of protection is usually in proportion to the

importance of its data. Medical data should be highly protected.

Information about current viruses is available from vendors and government agencies

dedicated to system security, such as those listed in Table 11.5.

Firewall - is a set of hardware and/or software designed to protect a system by disguising its IP address from outsiders who don’t have authorization to access it or ask for information about it.

The typical tasks of the firewall are to:• log activities that access the Internet• maintain access control based on the senders’ or

receivers’ IP addresses• maintain access control based on the services that are

requested• hide the internal network from unauthorized users

requesting network information• verify that virus protection is installed and being

enforced• perform authentication based on the source of a request

from the Internet

shows the threats (viruses, worms, and Trojans) as of September 2009.

proxy server - hides important network information from outsiders by making the network server invisible.

Authentication - is verification that an individual trying to access a system is authorized to do so.

Kerberos - One popular authentication tool.- The Kerberos protocol uses strong cryptography (the

science of coding messages) so that a client can prove its identity to a server, and vice versa, across an insecure network connection.

Using Kerberos, when client A attempts to access server B, the user is authenticated (a) and receives a ticket for the session (b). Once the ticket is issued, client and server can communicate at will (c). Without the ticket, access is not granted.

EncryptionThe most extreme protection for sensitive data is with

encryption—putting it into a secret code.private key - is a pair of two prime numbers (usually

with 75 or more digits each) chosen by the person who wants to receive a private message.

public key - Once the message receiver has the product, k, it can be posted in any public place, even an online directory, for anyone to see, because the private key can’t be decoded from the public key.

Packet sniffers also called sniffers - are programs that reside on computers attached to the network.

Spoofing - is a security threat that relies on cleartext transmission whereby the assailant falsifies the IP addresses of an Internet server by changing the address recorded in packets it sends over the Internet.

Password ManagementPasswords - are one of the easiest and most effective

protection schemes to implement, but only if they’re used correctly.

There are several reliable techniques for generating a good password:

• Using a minimum of eight characters, including numbers and non-alphanumeric characters

• Creating a misspelled word or joining bits of phrases into a word that’s easy to remember

• Following a certain pattern on the keyboard, generating new passwords easily by starting your sequence with a different letter each time

• Creating acronyms from memorable sentences, such as MDWB4YOIA, which stands for: “My Dog Will Be 4 Years Old In April”

• If the operating system differentiates between upper- and lowercase characters (as UNIX and Linux do), users should take advantage of that feature by using both in the password: MDwb4YOia

• Avoiding any words that appear in any dictionaryNumber of combinations of passwords depending

on their length and available character set.

Dictionary attack - is the term used to describe a method of breaking encrypted passwords.

Password Alternativessmart card – a credit-card-sized calculator that

requires both something you have and something you know.

Biometrics - the science and technology of identifying individuals based on the unique biological characteristics of each person.

A graphical password iscreated by clicking certainareas of the photo in acertain sequence.

Social Engineering - means looking in and around the user’s desk for a written reminder, trying the user logon ID as the password, searching logon scripts, and even telephoning friends and co-workers to learn the names of a user’s family members, pets, vacation destinations, favorite hobbies, car model, etc.

Phishing (pronounced “fishing”) - is a form of social engineering whereby an intruder pretends to be a legitimate entity and contacts unwary users asking them to reconfirm their personal and/or financial information.

Ethicsethics—the rules or standards of behavior that

members of the computer-using community are expected to follow, demonstrating the principles of right and wrong.

For the system’s owner, ethical lapses by authorized or unauthorized users can have severe consequences:

• Illegally copied software can result in lawsuits and fines of several times the retail price of each product for each transgression. Several industry associations publish toll-free numbers encouraging disgruntled employees to turn in their employers who use illegal software.

• Plagiarism, the unauthorized copying of copyrighted work (including but not limited to music, movies, textbook material, databases), is illegal and punishable by law in the United States as well as in many other nations. When the original work is on paper, most users know the proper course of action, but when the original is in electronic form, some people don’t recognize the ethical issues involved.

• Eavesdropping on e-mail, data, or voice communications is sometimes illegal and usually unwarranted, except under certain circumstances. If calls or messages must be monitored, the participants should always be notified before the monitoring begins.

• Cracking, sometimes called hacking, is gaining access to another computer system to monitor or change data, and it’s seldom an ethical activity. Although it’s seen as a sport by certain people, each break-in should cause the system’s owner and users to question the validity of the system’s data.

• Unethical use of technology, defined as unauthorized access to private or protected computer systems or electronic information, is a murky area of the law, but it’s clearly the wrong thing to do. Legally, the justice system has great difficulty keeping up with each specific form of unauthorized access because the technology changes so quickly. Therefore, system owners can’t rely on the law for guidance. Instead, they must aggressively teach their users about what is and is not ethical behavior.

How can users be taught to behave ethically? A continuing series of security awareness and ethics communications to computer users is more effective than a single announcement. Specific activities can include the following:

• Publish policies that clearly state which actions will and will not be condoned.

• Teach a regular seminar on the subject including real-life case histories.

• Conduct open discussions of ethical questions such as: Is it okay to read someone else’s e-mail? Is it right for someone else to read your e-mail? Is it ethical for a competitor to read your data? Is it okay if someone scans your bank account? Is it right for someone to change the results of your medical test? Is it acceptable for someone to copy your software program and put it on the Internet? Is it acceptable for someone to copy a government document and put it on the Internet?

THE END: THANK YOU!!!