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CSCI E-170 Security, Privacy and Usability Trends of Spyware, Viruses and Exploits
This paper surveys spyware, viruses and exploits, collectively called malware. The first section discusses the objectives of malware. The second section addresses its anatomy and distribution mechanisms. Mitigation is addressed in the third section, and fourth section addresses the relationship between usability and risk mitigation. 1.0 Objectives of Malware
This portion of the research addresses the objectives of spyware, viruses and exploits. This portion takes the approach of first enumerating the objectives, with some historical context, and illustrates a taxonomy as put forth by a leading AV publisher. We try to put the most innovative objectives first, and the more pedestrian last. We also show that the objectives are often combined. 1.1 Highly-specific targeted attacks (cyberwar, espionage)
In a talk this author attended, Hal McConnell - Retired NSA, and National Cryptologic Museum Docent, spoke to the Blackhat 2000 audience on “Threats from Organized Crime and Terrorists” in which he described both a cyber-surveillance project conducted by the National Security Agency, and a counter-attack against the NSA computers performed by their surveillance target. The counter-attack took NSA systems offline for three days, according to Mr. McConnell.1 Interestingly, major media had previously reported on the then-mysterious three-day outage of the NSA systems, and one online journal reported the following disinformation: “WASHINGTON (CNN) -- U.S. government sources say there is no indication that the crash of an important spy computer operated by the super secret National Security Agency was caused by sabotage or the Y2K glitch.2 “ Though first disclosed to be used in 2000, the threat posed by targeted virus attacks has recently re-surfaced as described by in the context of industrial espionage. In July of 2005, Israeli police working in conjunction with British authorities arrested 18 people in connection with a custom-written virus used for industrial espionage.3 Antivirus publishers rely on both networks of honeypots, and statistics derived from their antivirus software, to identify new forms of malware. This reliance created the vulnerability wherein low-volume, targeted viruses could safely be addressed to targeted entities; the honeypots would not detect these because they are not widespread, thus would not generate entries in the publishers' databases. The ramification of this type of attack is that mitigation measures, mentioned in this paper, would not suffice in mitigation. In the absence of wide distribution of the code, antivirus firms do not have the ability to generate signature files for the targeted viruses. Corporations, relying on AV software and other generally-available countermeasures, do not have the capability to defend against these targeted viruses. CSCI E-170 Security, Privacy and Usability
1.2 Digital Rights Management
One of the first viruses ever reported was the Brain virus of 1986 which originated in Pakistan.
Reports of its purpose differ among journals; however the BBC reported that its purpose may
likely have been an anti-piracy measure on the part of its authors.4
DRM measures today still often employ malware variants. For example, Sony has recently come
under scrutiny for utilizing rootkit technology in its attempts at DRM. Their work is a watershed
in the area of spyware, and has garnered the attention of the Department of Homeland Security
w/r/t its ramifications. Comments from DHS Assistant Secretary of Policy warned industry
leaders against utilizing DRM-objective spyware in any way which undercuts the security of the
US Critical Infrastructure.5
Similar to the targeted objectives of the NSA virus, the Sony DRM eluded the signature databases
of AV vendors until it was brought into the attention of mainstream media by
1.3 Malware for profit

ƒ Denial of Service attacks

Stacheldraht, as analyzed by Dave Dittrich, showed that one of the late-1990's objectives of
malware was denial of service attacks.6 The program Stacheldraht was later incorporated into
many rootkits.
Remote control was incorporated into stacheldraht. The programming practice of
incorporating remote control with denial of service capability was also demonstrated by the
Windows-based Sub-7 Trojan.
The practice of incorporating remote control into trojans provides a way of monetizing the
virus-infected systems. Bot-farms are sold and leased for mass emailings and for DDoS
applications. Farms of several thousand remotely controllable systems can be bought for a
few hundred dollars. In November of 2005, the FBI / DOJ released information on the arrest
and indictment of James Ancheta, whom the press release referred to as a “computer virus
broker”, and enumerated some of his specific profits from the monetization of malware.7

Though relaying email may sound to be an innocuous objective of malware, it is actually a
multimillion dollar business. And here we look to Symantec’s taxonomy of viruses:
Symantec ( describes a "Damage" category in which they enumerate the capabilities of a virus's payload. As an example Symantec8 describes the capabilities of W32.Nimda.E@mm as: o Large scale e-mailing: Emails itself out as Sample.exe o Degrades performance: May cause system slowdown CSCI E-170 Security, Privacy and Usability o Compromises security settings: Creates open network shares
ƒ Keylogging/PII
The acquisition of personally Identifiable Information, such as SSN’s, Financial account
information et al. are frequently the objectives of hostile code. Keylogger.Stawin is an
example of one such virus. Other viruses in the multifunction category frequently include
ƒ Product tracking

As an example in the “product tracking” category of spyware, Compaq systems install an
application called ‘backweb’ on the systems sold to consumers. Backweb is a lightweight
web server. It uploads system data to Compaq’s databases, and downloads messages and
software from Compaq. It may be considered to be in a gray area of spyware, inasmuch as
although Compaq does little to notify and end-user of its existence, Compaq does present data
about it on its website.
ƒ Surfing/Marketing data

“Legitimate” firms such as Webtrends provide software which embeds web-bugs into pages
created with their software. Wired with such bugs, the pages then provide updates to the
Webtrends site, which feeds back aggregated information to the Webtrends subscriber.
ƒ Click fraud

As new revenue models are created for internet usage, viruses are coded to exploit those
revenue models. One Revenue model is pay-per-click, wherein clicks on ads return money to
the web site which hosts the ads. Viruses are used to automate the hits, and compromised
systems return hits for the users of the hostile code.
ƒ Pharming
Pharming is a practice wherein unsuspecting users are directed to hostile sites which imitate a
legitimate site in order to collect personally identifiable information such as financial
resources. A method of pharming involves substituting host files on the target systems, such
that DNS resolution of a legitimate site then points to a hostile site.
ƒ P2P functionality

Virus code, like any code, is re-used while additional functionality is added to core
functionality. P2P capability has been added to a number of viruses. The capability can be
used for distributing hostile code, or even just for filesharing of any general type.
ƒ Multifunction objectives

Novarg as an example of a multifunction virus enables mass e-mail (SPAM), plus DDoS
capabilities, plus remote control.
In Symantec's taxonomy, it is shown as:
CSCI E-170 Security, Privacy and Usability Large scale e-mailing: Sends to email addresses found in a specified set of files. Degrades performance: Performs DoS against Compromises security settings: Allows unauthorized remote access. 1.4 Malware for malice and publicity

ƒ File deletion

File deletion is a capability used by many viruses, but often not a main objective. For
example, in the Melissa series of viruses, only at version F was file deletion introduced. The
“I love you” virus, on the other hand, used file deletion as its main objective.
ƒ Publicity/Props

The motivation of virus authors trying to make themselves known is still prevalent today.
MSNBCreported on a war of words which was coded into Netsky and Bagle. The Netsky
code read: “Bagle – you are a looser!!!” and the Bagle virus code held the text: "Hey,
NetSky . don't ruine {sic} our bussiness, wanna start a war ?"

2.0 Malware Mechanisms
This week marks the 20th birthday of the first virus that was introduced by Fred Cohan at the
University of Southern California.9 They were experimental and mainly for entertainment
purposes. Since then, viruses have been evolving and becoming more sophisticated as well as
malicious; they delete files, exploit operating systems’ and applications’ vulnerabilities They can
open doors for hackers to gain access to a computer or even a network.
According to Trend Micro’s Real-time Virus map which collects data from its free, online
scanner for PCs, more than 15,000 PCs are infected with different types of viruses daily but this
number is just a fraction from the real number of infected clients out there.10
2.1 What is Malware?
Malware is a general term that usually refers to spyware, viruses, and exploits such as worms and
Trojans. It is a program that performs malicious, unauthorized and unexpected actions. Below
are some examples of the Malware we will be discussing.
A computer virus is typically a small executable code that can replicate itself. It can attach
itself to other executable programs and can spread as files that are copied and sent out to
different clients. The virus can do many things from displaying messages, images,
consuming memory, and CPU processing power to destroying files, reformatting the hard
drive or causing other damages.
CSCI E-170 Security, Privacy and Usability Trojan horse
Trojans are programs that look harmless or desirable but it contain the malicious code that
does damage to the system. Trojans frequently replicate themselves. Examples of this type of
malware are:
-Remote Access Trojans which open backdoors for hackers to examine the local system
-Rootkits which also open backdoors and allow hackers to perform more activities.
Using security holes, a computer worm is software that replicates itself to other computer
system via email attachments and network connections such as instant messaging software
and peer-to-peer networks

2.2 Anatomy of Malware
We will discuss the anatomy of malware by breaking it down into three different areas. These
areas are the creation stage, distribution methods and finally the malware payloads and triggers
Creation stage
With the availability of tools, technology and help out there, it is no longer difficult to write
and distribute a malware to the public. Anyone with a computer, Internet access and some
basic programming skill can create a malware.
In order to plan a successful attack, malware creator decides what target environment is and
write specific code for that. Here are some typical examples:
Applications environment: Using other installed application to execute the malware. Operating systems environment: malware takes advantage of un-patched systems using a known vulnerability or security holes to attack the system. In addition to the target environment, malware creator also considers the object that it infects. Examples are: Boot Sector: This refers to the MBR (master boot record). The malware will execute when an x86-based computer starts up, before the operating system is loaded. Macros: This refers to applications that support macro scripting such as spreadsheet, word processor application. Execution of the macro script will activate the malware. This refers to scripting language files such as Java script, Visual Basic script. Executable: This refers to typical executable files such as the ones with extensions such as .exe, .com, .dll, .sys, .ocx. Distribution Methods:
There are different methods that malware uses to propagate and replicate to different
computer system. The common methods are:11
CSCI E-170 Security, Privacy and Usability A popular mailing list can contain over 100,000 subscribers. Malware creator can create the malware, carefully plant it in the email with an attractive subject and send it out using one of many mass e-mailer programs that are widely available for a small cost or for free. Malware creator can use one of many free email accounts that is hard to trace back. In no time, the email that contains this malware arrives in thousands of mailboxes. The human factor is usually the easiest target. Malware creators know this and usually take it into consideration and change the name of the executable files to include multiple extensions because most people know not to run EXE extension. Some examples are: -Adding a non executable extension to executable file: myPic.exe changes myPic.jpg.exe or myPic.gif.exe -Making the malware to screen saver format: screen_saver.scr -Embedding the malware to wma files. Once it is executed, the malware may behave as expected by displaying text or images and in the same time spreading and infecting other files and computer. Depends on the type of email clients and its vulnerabilities, some email clients can set off the executable when user opens the email / auto-execute. If it is a link, the file can be downloaded from a web server. Via Instant messenger Instant messaging is relatively new yet can be the next new breeding grounds for malware. According to computer researchers, because of its "scale-free" networks structure, it is highly susceptible to virus infections. IM malware spreads itself, by using popular instant messaging service such as MSN, Yahoo, and AIM, to other instant clients using the file transfer feature of the program. User when click on the link that may contain the link that points to a different malware can be downloaded and executed on the local system. Via Network shares The most common spreading and propagation method that is used by malware today is via network shares. Peer-to-peer: In P2P networks, users install a client program to transfer files privately. These channels are created using common port such as 80 thus bypassing firewall. Malware creator uses this transport mechanism to spread and infect computers. Exploits: By using vulnerabilities and security holes, malware takes advantage of un-patched systems to take over a system. Malware then will replicate and spread to other computer systems. Via Network scanning This method is quite popular. It is said that when an un-patched computer connects to the Internet, it will likely be compromised in a very short time. Malware creator scans the open ports of a range of IP address and look for vulnerable computer to attack. CSCI E-170 Security, Privacy and Usability Payloads and Trigger Stage
After a successful deployment malware can do any of the following, depending the on
programmed trigger mechanism:12
Self execution: malware executes its attack by itself. User dependent: user runs the program that will execute the malware. Logic bomb: an action from user can trigger the malware. Time bomb: malware can execute or stop on or after a certain date and time. Upon execution, malware can do any of the common activities: Install as Service: In the local system, the malware installs itself as a service. Because services are run before and after the user logs in or out, it can continue its own thing and also has better chance not getting detected by malware utilities program. Register in startup key: In the local system, the malware places itself in one of the startup keys such as HKEY_ Local_Machine\SOFTWARE\Microsoft\ Windows\CurrentVersion\Run. This enables the execution of the malware every time user logs in. 13 Data deletion / theft / corruption: malware quickly delete data on local hard drive or shared drives using the permission from the current user System failure: malware attacks the application or operating system by finding their weakness and cause the system to shut down or malfunction. Network bandwidth flooding: malware can send packets to multiple random or pre-programmed ranges of IP addresses using a pre-selected port. Other infected computer systems, in turn, will do the same thing. In no time, all traffic will be halted. Backdoor opening: malware install backdoors for remote access such as setting up FTP. Malware creator then gains access to the system. 3.0 Mitigation
Thoughtful users have a myriad of options available in mitigating the effects of malware. These
defenses are essentially divided into three areas; deterrence, prevention, or detection and
response. They attempt to solve the problem by either good design or feedback; open-loop or
closed-loop. Each of these areas, while providing unique resistance capabilities, is not without
weakness. The shortcomings are inherent to their strengths.
Deterrence, for example, is primarily based on and limited by legal actions. Prevention strategies
require a hardening of systems, potentially self-defeating as usability is diminished. Detection
and response is predominately the arena of scanning products, an open-loop approach to an
adaptive problem.
3.1 Deterrence
The ever increasing onslaughts are prompting enterprises to pursue legal actions as a form of
deterrence. While this trend should reduce the motivation of attackers, in practice it is
problematic. The interpretations of jurisdictional and legal issues show few signs of reaching
sustainable clarity.
Recent legislation is the Securely Protect Yourself Against Cyber Trespass Act, also known as the
SPY Act, the Internet Spyware (I-SPY) Prevention Act and the Software Principles Yielding
Better Levels of Consumer Knowledge Act
, unsurprisingly known as the SPYBLOCK Act.14
CSCI E-170 Security, Privacy and Usability
The U.S. House of Representatives has passed both the SPY Act and the I-SPY Act. While their
long-term effectiveness remains in doubt, they do appear to be having the desired effect.
Enterprises now have the option of taking legal action against entities for the damages resulting
from non-secure products, particularly if the vulnerabilities are well known and continue to be
There remain areas of broad interpretation. While prohibiting the unauthorized installation of
software may seem simple enough, what constitutes authorization? Court rulings such as DeJohn
v. The .TV Corporation International
and Bruce G. Forrest v. Verizon Communications Inc. and
Verizon Internet Services
have upheld the concept of click-wrap agreements - essentially allowing
contracts to be consummated on a mouse-click.15 Similarly, while prohibiting exploits may seem
sensible, what defines exploits? One man’s spyware may be another’s legitimate product. These
areas show no sign of being resolved in the near-term.
Even the idea of classifying legitimate vendors by an opt-in versus opt-out scheme suffers from
shortcomings. Opt-out effectively implies that the burden is an individual to alert a potential
sender that they do not want anything sent in the first place. But unlike telemarketers, there are
an unlimited amount of Internet senders, rendering this scheme impractical.
A more effective opt-in scheme would be one where it is illegal to solicit recipients who have not
explicitly requested an opt-in. Obviously this would have no effect on illegitimate senders.
3.2 Prevention
Exploits can be limited through the use of network separation, the use of surety systems, change
management, and a variety of other protective mechanisms.
Enterprises can employ risk-avoidance strategies. They can refuse to run products that are known
to be susceptible to exploits. They can, for example, choose to employ hardened systems in lieu
of the Microsoft platforms. Paradoxically, enterprises are trending towards the increased, not
decreased, use of Microsoft systems. Some organizations, for example, have created vulnerable
environments by replacing closed systems such as hospital equipment and Teller machines
(ATM) with networked Windows systems.
Of course, risks would be minimized with preventative thinking. The infection by an Internet
virus implies that the system was accessible from the Internet to begin with. Network zoning and
separation are reasonable mitigation approaches.
Another mitigation approach is establishing a separation of user data from externally facing
applications. Once periodic checkpoints of the data are established, it becomes trivial to rollback
to a known uncompromised checkpoint.
Another recent trend is the use of augmented authentication mechanisms. These systems limit the
extent to which unauthorized software can access unrelated information. The keyring system
combined with access control lists (ACLs) used by OS X is such a system. If application A is
compromised, only information available to application A is compromised. Windows XP has a
somewhat analogous mechanism called CredUI that allows for the secure storage of passwords.
CSCI E-170 Security, Privacy and Usability Recommended Windows based spyware defense strategies16:
Disabling ActiveX or replacing Internet Explorer with a less vulnerable browser is another
strategy to consider. This alternative is also a less than perfect approach. ActiveX is sometimes
required by websites and IE may even be embedded in the operating system. Again, the balance
between usability and security must be weighed.17
3.3 Detection and Response
The security industry has been slow to address the spyware problem. Nor does there appear to be
spyware products designed for large organizations. At this time, the process of removing
spyware requires multiple approaches and can be more of an art than science. Spyware has
shown itself to be remarkably resistant to complete removal.18 There do remain, however, actions
that can be taken.19 They are imprecise and require changes in organizational cooperation and
behavioral buy-in.

CSCI E-170 Security, Privacy and Usability The following table represents available options. Configuration management tools (CMDB, archived redo- Registry and browser policy restrictions Thin-client with disposable browser sessions Port blocking Specialized user training All the security in the world cannot always and completely protect an organization. Signature based virus detection, for example, is becoming increasingly obsolete.20 The introduction of Instant Messaging and its own set of problems are trending negatively. The proliferation of wireless brings its own dimension to these challenges. It is clear the most important long-term initiatives for an enterprise to adopt are: ƒ Forewarned is forearmed. The amount of threat and vulnerability information can be
overwhelming to the point it is ignored. Enlisting a third-party security intelligence firm can improve the signal-to-noise ratio while providing customized advice on specific threats.
ƒ Improvise, Adapt and Overcome. Good design is not enough. Looking for a static set
of predefined conditions like signature matching or comparing for known vulnerabilities is insufficient. Feedback mechanisms are necessary. For example, detecting zero-day problems require a profile of normal activity, and then responding when that activity strays outside of normal baselines.
ƒ Strengthen the weakest link. The weakest element of any security initiative is the
human element. While acceptable use policies (AUPs) are a good start, it is not enough. Cultural change, in the form of experiential learning, accountability and disciplinary action, should be included in any security program.21
ƒ Share the Burden. Even if a business process is outsourced, the liability and publicity
resulting from a breach will fall squarely on the owner’s shoulders. Ensure partners are subject to stringent contractual security requirements. CSCI E-170 Security, Privacy and Usability For the private user, the following long-term activities would apply: ƒ A little education goes a long way. Ignoring the problem has not worked. By accepting
the burden of understanding the problem, users can avoid the most common mistakes.
ƒ You are likely already infected.22 Install quality malware scanning software. Note that

ƒ Avoid re-infections. Install quality anti-spyware and virus protection software.
ƒ Be proactive. Lock down Internet Explorer. Place bad sites on a restricted zone.
Consider an alternative browser such as Opera or Firefox. Consider outbound filtering and blocking.
4.0 Risk Mitigation and its Effect on Usability

Organizations and home users want to protect their information. This information can be in the form of financial data, trade secrets, and customer data. This data more than likely is
stored on a computer or server. Chances are that the computer or server are connected to a
network that is directly connected to the Internet. The Internet is available to anyone with access.
The challenge that organizations and home users face is determining how to protect this
electronic information from the risks outlined in the first two sections of this paper. The
preceding section outlined some methods available to mitigate the risks posed to organizations
and home users. These methods however impose controls and parameters on the user which
affect usability. This section will discuss the effects of information security risk mitigation
measures on usability. We will review these effects within the contexts of internal security and
perimeter security as well as in regards to organizations and home users.
4.1 Internal Security

Research23 concludes that information security is at greater risk from internal users versus external users. Internal users have direct access to an organization’s data. In turn organizations have developed many information security policies and implemented many technologies to mitigate the risk to its data. Some of these technologies include: • Complex passwords and short password expiration intervals • Dual form authentication • Biometrics • Role based security • Host based virus and spyware scanners Information security policies will vary based on the industry, implemented technologies and industry compliance requirements. At the core of most information security manuals is a company’s “Acceptable use Policy.” This policy broadly defines what is acceptable and not acceptable use of technology resources within an organization. This policy typically references CSCI E-170 Security, Privacy and Usability an organization’s disciplinary policy in the event that “not acceptable” use is deemed to have taken place. While these mitigation strategies are placed in the best interest of the organization they can at times cause unexpected problems. These problems are encountered by both the users and the organization’s staff whose responsibility is to monitor and enforce the information security technologies and policies implemented. The problems encountered by users are in the area of access and use of the protected information. Organizations that have data to protect will have some type of authentication mechanism. The basic method of authentication is establishing a unique password for all users. A large number of organizations have adopted the best practice of using strong passwords and forcing users to change them frequently. This poses a challenge for users who need to keep track of an increasing number of passwords and complexity. In turn users will opt to write the password down instead of remembering it. This is writing down of passwords is a security risk however it is a response to the controls placed in a user’s environment. Once a user is authenticated on the network she has access to resources which she has been given explicit access to. Within the network the user is faced with a wire variety of additional security measures. These measures include role based security which defines what data the user has access based on her particular role. Role based security is also propagated down to the application that the user uses. The user can be denied access to data or system functions she needs access to if the security rules are not well designed. Role based security can also be linked with the level of Internet access a user is granted. There are wide array of products that an organization can implement to filter sites with questionable content. Some of these products include Microsoft ISA Server, Surfcontrol Web filter and Websense Web filter. The challenges with these products are that some are based on keywords and others site definitions or both. Keyword based filters look for words within a site which are defined as inappropriate by the organization and block access to the site. The challenge with this setup is that the filter can block out legitimate sites if the keyword dictionary is poorly defined or not maintained. For example an investment bank might block sites with content including the word “Viagra” however this might hot work in a healthcare facility were a doctor might be looking for a drug-drug interaction with the drugs “Zoloft” and “Viagra.” Some products, specifically Surfcontrol’s Web Filter uses categories to define sites to block. The challenge here is that this is manual process performed by Surfcontrol staff. The Internet is very dynamic and sites appear every day. This risk of missing a new site or mis-categorizing a site can lead to problems for the user. The same risks can be stated for email filters which filter emails using content keywords, attached file types and SPAM blacklists if the filter is designed to filter such traffic. It must be noted that web and email filters can be categorized as perimeter security however their effects are directly affect usability and internal security. Home users might not have all the challenges that users operating within an organization have in regards to usability issues. Home users also need to be concerned about viruses and exploits. Organizations might have the ability to setup automated virus definition updates and spyware scans on corporate PCs. Home users on the other hand might not have the expertise to setup such tasks on their PCs. Security software developers are aware that a majority of users might not comprehend all the risks posed to their data which in turn will lead to lack of understanding on how to apply security solutions. In response security software developers have designed programs that are user friendly and ready to run out of the box. This is beneficial to users if everything runs properly and the software packages are kept up to date. In the event something does go wrong with the software such as in the case of an expired antivirus license or corrupted installation a user might not have expertise to detect and correct the problem. This is turn exposes the user to risks. CSCI E-170 Security, Privacy and Usability 4.2 Perimeter Security
Perimeter security an organization’s first line of defense against intrusions. An organization’s perimeter is its outward facing network. An outward facing network is a network that is accessible to external entities. Web servers, email servers and web portals usually reside on an outward facing network. Perimeter security for an outward facing network is usually handled by a network security device or appliance such as a firewall. The firewall’s sole purpose is to guard the perimeter and prevent intrusions or rogue code from entering. Firewalls accomplish this by using packet filters, antivirus detection, intrusion detection mechanisms and access control lists. These measures are effective in guarding against existing threats. In regards to new threats, the firewall must be updated and reviewed regularly so these threats can be identified and addressed. Historically, organizations have placed a large focus on perimeter security. Organizations have invested a great deal of financial resources in network firewalls, intrusion detection and intrusion prevention devices. Unfortunately, firewalls and perimeter security devices give organizations a false sense of security. This is because most information security breaches are from internal sources as stated earlier in this paper. However perimeter security is a very important of an organization’s information security strategy. Usability issues with perimeter security are not necessarily directly felt by the end users except for the effects of web and email filters. Instead usability issues are felt the system administrator who are tasked out to configure and manage these perimeter security devices. The devices and solutions which make up an organization’s perimeter security must be configurable and adaptable to deal new threats. The devices should also provide administrators with relevant and actionable information. Mid and large size organizations’ perimeter can be extensive however home users do not the need such systems. Home users do need perimeter protection and thus the vendors who provide solutions for large organizations also provide home user versions of their products. Perimeters products geared to the home user have easily configurable settings presented in a user friendly interface. The interfaces are typically web based as in the case with NetGear’s FVS318 Home Firewall. The security features included in these devices are not as extensive as their enterprise level counterparts. However it is still challenging for the lay user to understand all the risks that exist in the Internet and thus fully understand the proper implementation of a home firewall. A poorly configured firewall can be as dangerous as having no firewall at all. The high availability of the Internet is a concern for home users in that there are a large number of sites with content which might be considered inappropriate to some users. PC based software firewalls and hardware based firewalls offer some protection but not to the degree that enterprise class system provide. They provide protection by offering similar filtering capabilities however the burden is on the home user to configure the firewall based on their web browsing requirements. Online service providers such as America Online have a “Parental Controls” solution which relieves home users from this complicated task by offering a configurable control panel to manage all aspects of web content filtering. However, America Online users represent a small fraction of total Internet users. Microsoft’s Internet Explorer comprises the majority of Internet browser use. While we suggested in the preceding section that an approach to mitigate risks with IE would be to disable ActiveX controls and setup browsing zones, this might task might be challenging to a lay user. CSCI E-170 Security, Privacy and Usability 5.0 Conclusion

In this paper we have defined and discussed the objectives of malware. We also examined some of the mechanisms which are used by malware to accomplish its objectives. We also provide some risk mitigation strategies that organizations and regular users can use to protect themselves. Risk mitigation technologies however are not effective unless the end user can easily modify them to adapt to new threats. Additionally the risk mitigation solutions must also provide feedback to the user so she can react and take action where needed. The nature of technology is very dynamic. Users are faced with new products and solutions too frequently to learn about them in any depth. Users are also faced with new threats on almost a daily basis. The amount of information to sift through can be daunting. It is however necessary to at least have a basic understanding of malware and its potential risks. This is also true of the available risk mitigation techniques and technologies. A user’s best defense is indeed education. CSCI E-170 Security, Privacy and Usability
6.0 Works Cited
1 Hal McConnell, Luncheon talk at BlackHat Conference, Las Vegas, Nevada July 27 2000.
2 CNN.COM “US Intelligence computer crashes for nearly 3 days” as visited 11/15/2005.
3 “Latest Online Menace: Custom Worms Built for Industrial Espionage” as visited 11/7/2005.
4 BBC.CO.UK “Computer Viruses now 20 years old”
as visited 11/18/2005.
5 Brian Krebs on Computer Security “DHS Official Weighs In on Sony” as visited 11/18/2005.
6 Dittrich, David (1999). “The ‘stacheldraht’ Distributed Denial of Service Attack Tool” as visted 11/20/2005.
7 USAO/CDCA Press Release 11/3/2005 “Computer Virus Broker Arrested for Selling Armies of Infected
Computers to Hackers and Spammers” as visited
8 Viruses & Risks --
[email protected] as visited 11/19/2005.
9 BBCNews, “Computer viruses now 20 years old”
/2/hi/technology/3257165.stm . Retrieved on November, 2005
10 Trend Micro, “Virus Map”. Retrieved on November, 2005
11 Danchev, Dancho (2004) “Malware – It’s Getting Worse”. Retrieved Nov., 2005
12 Klinder, Bernie (2002) “Computer Virus Primer for Network Administrator” Retrieved Nov., 2005
13 Grimes, Roger (2003). “Life Cycle of an E-mail Worm”. Retrieved Nov., 2005
14 Cody, Jason Allen (2004). “Congressional Attack on Axis of Internet Evil “ Retrieved Nov., 2005
15 Samson, Martin (2005). “Internet Law: Click-Wrap Agreement” Retrieved Nov., 2005
16 Cohen, Fred (2005). “Enterprise Strategies for Defending Against Spyware.” Burton Group Research
17 Friedlander, David (2004). “What to Do About Spyware.” Forrester Research 35770
18 Girard, John (2004). “Spyware Tales from the Analyst Files”. Gartner Research COM-23-2333
19 Pescatore, John (2004). “Preventing and Removing Spyware”. Gartner Research DF-23-1794
CSCI E-170 Security, Privacy and Usability 20 Hallawell, Arabella (2001). “Signature-based Virus detection at the Desktop is Dying.” Gartner Research SPA-14-0415 21 Leong, Lydia (2004). “Companies Must Fight Spyware with Tools, Not Words.” Gartner Research DF-23-2614 22 Freidlander, David (2005). “Antispyware Adoption in 2005.” Forrester Research 36312 23 Baum, Fraga, Kreizman and Sood (26June2002). “Security Imperatives for Leaders in a Networked World” Gartner Research COM-17-1102

Source:,%20Viruses%20and%20Exploits.pdf Cibles et mécanismes d'action : réversibilité : loi d'action de masse (fait intervenir les concentrations du médicament et de la cible) k+1, k-1 Le plus souvent, liaison faible, rarement covalence (aspirine → effet prolongés toujours) Affinité : inversement proportionnelle à la dose. Quand l'affinité Saturabilité : à l'origine des phénomènes de co

Microsoft word - hypothesis english version.doc

Ten guidelines for creating and using hypotheses Here is how to make a useful research hypothesis: STEP 1: THE QUESTION Our example starts with a small article in a journal for chemists. Scientists at the Technical University of Copenhagen had a test done with plastic pipes for drinking water. They had filled tubes with water in their laboratory and left it there for a couple of days. The

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