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Electronic Crime Essay, Research Paper
In the past decade, computer and networking technology has seen enormous
growth. It is now possible for people all over the world to communicate and
share information from virtually anywhere. This growth however, has not come
without a price. With the advent of the "Information Highway", as it’s
coined, a new methodology in crime has been created. Electronic crime has been
responsible for some of the most financially devastating victimizations in
In the recent past, society has seen malicious editing of the Justice
Department web page unauthorized access into classified government computer
files, phone card and credit card fraud, and electronic embezzlement. All these
crimes are committed in the name of "free speech." These new breed of
criminals claim that information should not be suppressed or protected and that
the crimes they commit are really not crimes at all. What they choose to deny is
that the nature of their actions are slowly consuming the fabric of our
country’s moral and ethical trust in the information age.
Federal law enforcement agencies, as well as commercial computer companies,
have been scrambling around in an attempt to "educate" the public on
how to prevent computer crime from happening to them. They inform us whenever
there is an attack, provide us with mostly ineffective anti-virus software, and
we are left feeling isolated and vulnerable. I do not feel that this defensive
posture is effective because it is not pro-active. Society is still being
attacked by highly skilled computer criminals of which we know very little about
them, their motives, and their tools of the trade. Therefore, to be effective in
defense, we must understand how these attacks take place from a technical
stand-point. To some degree, we must learn to become a computer criminal. Then
we will be in a better position to defend against these victimizations that
affect us on both the financial and emotional level. In this paper, we will
explore these areas of which we know so little, and will also see that computers
are really extensions of people. An attack on a computer’s vulnerabilities are
really an attack on peoples’ vulnerabilities.
Today, computer systems are under attack from a multitude of sources. These
range from malicious code, such as viruses and worms, to human threats, such as
hackers and phone "phreaks." These attacks target different
characteristics of a system. This leads to the possibility that a particular
system is more susceptible to certain kinds of attacks.
Malicious code, such as viruses and worms, attack a system in one of two
ways, either internally or externally. Traditionally, the virus has been an
internal threat (an attack from within the company), while the worm, to a large
extent, has been a threat from an external source (a person attacking from the
outside via modem or connecting network).
Human threats are perpetrated by individuals or groups of individuals that
attempt to penetrate systems through computer networks, public switched
telephone networks or other sources. These attacks generally target known
security vulnerabilities of systems. Many of these vulnerabilities are simply
due to configuration errors.
Viruses and worms are related classes of malicious code; as a result they are
often confused. Both share the primary objective of replication. However, they
are distinctly different with respect to the techniques they use and their host
system requirements. This distinction is due to the disjoint sets of host
systems they attack. Viruses have been almost exclusively restricted to personal
computers, while worms have attacked only multi-user systems.
A careful examination of the histories of viruses and worms can highlight the
differences and similarities between these classes of malicious code. The
characteristics shown by these histories can be used to explain the differences
between the environments in which they are found. Viruses and worms have very
different functional requirements; currently no class of systems simultaneously
meets the needs of both.
A review of the development of personal computers and multi-tasking
workstations will show that the gap in functionality between these classes of
systems is narrowing rapidly. In the future, a single system may meet all of the
requirements necessary to support both worms and viruses. This implies that
worms and viruses may begin to appear in new classes of systems. A knowledge of
the histories of viruses and worms may make it possible to predict how malicious
code will cause problems in the future.
To provide a basis for further discussion, the following definitions will be
used throughout the report;
Trojan Horse – a program which performs a useful function, but also performs
an unexpected action as well;
Virus – a code segment which replicates by attaching copies to existing
Worm – a program which replicates itself and causes execution of the new copy
Network Worm – a worm which copies itself to another system by using common
network facilities, and causes execution of the copy on that system.
In essence, a computer program which has been infected by a virus has been
converted into a "trojan horse". The program is expected to perform a
useful function, but has the unintended side effect of viral code execution. In
addition to performing the unintended task, the virus also performs the function
of replication. Upon execution, the virus attempts to replicate and
"attach" itself to another program. It is the unexpected and
uncontrollable replication that makes viruses so dangerous. As a result, the
host or victim computer falls prey to an unlimited amount of damage by the
virus, before anyone realizes what has happened.
Viruses are currently designed to attack single platforms. A platform is
defined as the combination of hardware and the most prevalent operating system
for that hardware. As an example, a virus can be referred to as an IBM-PC virus,
referring to the hardware, or a DOS virus, referring to the operating system.
"Clones" of systems are also included with the original platform.
History of Viruses
The term "computer virus" was formally defined by Fred Cohen in
1983, while he performed academic experiments on a Digital Equipment Corporation
VAX system. Viruses are classified as being one of two types: research or
"in the wild." A research virus is one that has been written for
research or study purposes and has received almost no distribution to the
public. On the other hand, viruses which have been seen with any regularity are
termed "in the wild." The first computer viruses were developed in the
early 1980s. The first viruses found in the wild were Apple II viruses, such as
Elk Cloner, which was reported in 1981 [Den90]. Viruses were found on the
These computers made up a large percentage of the computers sold to the
public at that time. As a result, many people fell prey to the Elk Cloner and
virus’s similar in nature. People suffered losses in data from personal
documents to financial business data with little or no protection or recourse.
Viruses have "evolved" over the years due to efforts by their
authors to make the code more difficult to detect, disassemble, and eradicate.
This evolution has been especially apparent in the IBM PC viruses; since there
are more distinct viruses known for the DOS operating system than any other.
The first IBM-PC virus appeared in 1986 [Den90]; this was the Brain virus.
Brain was a boot sector virus and remained resident in the computer until
"cleaned out". In 1987, Brain was followed by Alameda (Yale), Cascade,
Jerusalem, Lehigh, and Miami (South African Friday the 13th). These viruses
expanded the target executables to include COM and EXE files. Cascade was
encrypted to deter disassembly and detection. Variable encryption appeared in
1989 with the 1260 virus. Stealth viruses, which employ various techniques to
avoid detection, also first appeared in 1989, such as Zero Bug, Dark Avenger and
Frodo (4096 or 4K). In 1990, self-modifying viruses, such as Whale were
introduced. The year 1991 brought the GP1 virus, which is
"network-sensitive" and attempts to steal Novell NetWare passwords.
Since their inception, viruses have become increasingly complex and equally
Examples from the IBM-PC family of viruses indicate that the most commonly
detected viruses vary according to continent, but Stoned, Brain, Cascade, and
members of the Jerusalem family, have spread widely and continue to appear. This
implies that highly survivable viruses tend to be benign, replicate many times
before activation, or are somewhat innovative, utilizing some technique never
used before in a virus.
Personal computer viruses exploit the lack of effective access controls in
these systems. The viruses modify files and even the operating system itself.
These are "legal" actions within the context of the operating system.
While more stringent controls are in place on multi-tasking, multi-user
operating systems (LAN Networks or Unix), configuration errors, and security
holes (security bugs) make viruses on these systems more than theoretically
possible. This leads to the following initial conclusions:
Viruses exploit weaknesses in operating system controls and human patterns of
Destructive viruses are more likely to be eradicated and
An innovative virus may have a larger initial window to propagate before it
is discovered and the "average" anti-viral product is modified to
detect or eradicate it. If we reject the hypothesis that viruses do not exist on
multi-user systems because they are too difficult to write, what reasons could
exist? Perhaps the explosion of PC viruses (as opposed to other personal
computer systems) can provide a clue. The population of PCS and PC compatible is
by far the largest. Additionally, personal computer users exchange disks
frequently. Exchanging disks is not required if the systems are all connected to
a network. In this case large numbers of systems may be infected through the use
of shared network resources.
One of the primary reasons that viruses have not been observed on multi-user
systems is that administrators of these systems are more likely to exchange
source code rather than executables. They tend to be more protective of
copyrighted materials, so they exchange locally developed or public domain
software. It is more convenient to exchange source code, since differences in
hardware architecture may preclude exchanging executables. It is this type of
attitude towards network security that could be viewed as victim precipitation.
The network administrators place in a position to be attacked, despite the fact
that they are unaware of the activity. The following additional conclusions can
To spread, viruses require a large population of similar systems and exchange
of executable software;
Destructive viruses are more likely to be eradicated;
An innovative virus may have a larger initial window to propagate before it
is discovered and the "average" anti-viral product is modified to
detect or eradicate it.
Although many anti-virus tools and products are now available, personal and
administrative practices and institutional policies, particularly with regard to
shared or external software usage, should form the first line of defense against
the threat of virus attack. Users should also consider the variety of anti-virus
products currently available.
There are three classes of anti-virus products: detection tools,
identification tools, and removal tools. Scanners are an example of both
detection and identification tools. Vulnerability monitors and modification
detection programs are both examples of detection tools. Disinfectors are
examples of a removal tools. A detailed description of the tools is provided
Scanners and disinfectors, the most popular classes of anti-virus software,
rely on a great deal of a prior knowledge about the viral code. Scanners search
for "signature strings" or use algorithmic detection methods to
identify known viruses. Disinfectors rely on substantial information regarding
the size of a virus and the type of modifications to restore the infected file’s
Vulnerability monitors, which attempt to prevent modification or access to
particularly sensitive parts of the system, may block a virus from hooking
sensitive interrupts. This requires a lot of information about
"normal" system use, since personal computer viruses do not actually
circumvent any security features. This type of software also requires decisions
from the user.
Modification detection is a very general method, and requires no information
about the virus to detect its presence. Modification detection programs, which
are usually checksum based, are used to detect virus infection or Trojan horses.
This process begins with the creation of a baseline, where checksums for clean
executables are computed and saved. Each following iteration consists of
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