Antivirus software uses various methods like signatures, heuristics, and real-time protection to identify malware like viruses, worms, and trojans. It works by scanning files and comparing them to known virus signatures. While antivirus software is useful for protecting devices from malware, it also has limitations like unexpected renewal costs, potential false positives, and reduced effectiveness against new viruses. Antivirus software must also contend with techniques used by malware authors to avoid detection, such as rootkits that have full system access.

1. ANTIVIRUS SOFTWARE
Abstract:
The topic “Antivirus Software” deals with a
software which is used to prevent or detect
malware. This abstract discusses the
definition of Antivirus Software,
Identification processes generally used by
antivirus software available in the market
and their assets, etc. It also discusses the
current issues faced by the user by the
market available antivirus software and
concludes with the main points.
Introduction:
Antivirus software is used to prevent, detect
and remove all sorts of malware such as
computer viruses, hijackers, worms, Trojan
horses, etc. They are offered as products and
services by antivirus software companies.
History:
Most of the viruses in early & mid 1980s
have been limited in self-reproduction
spread initially by storage devices such as
floppy disks, before internet connection was
wide spread. The first anti-virus introduced
was Flushshot Plus and Anti4us in 1987.
Later, John McAfee and Eugene Kaspersky
found their own methods of solving malware
problems through anti-virus software and
later setup their own companies producing
the anti-virus software in 1988.
Identification methods:
There are various methods used by Antivirus
software to identify malware:-
1. Signature based tools: Most
commonly used to identify viruses
and other malware, antivirus
software compares the contents of a
file to a dictionary of virus
signatures. As viruses can embed
themselves in existing files, the
entire file is searched, not just as a
whole but also in pieces.
2. Heuristics: Heuristic is a technique
designed for solving a problem more
quickly when classic methods are too
slow or are unable to find the exact
solution. Some anti-viruses are
difficult to detect as they start of a
single infection and later change into
many variants. Heuristics is a
method followed to counter them.
3. Root kit detection: Root kit is one of
the most dangerous malware
designed to gain administration-level
control over the computer without
detection. They change the way
operating systems function and
tamper anti-virus, leaving it
ineffective.
4. Real-time protection: Background
guard, auto protect, risky website
testing, etc are some other anti-virus
protection provided by Anti-virus
software.
Some popular anti-viruses:
• Kaspersky Lab
• McAfee Virus Scan
• Avira Antivirus Software

2. • Avast! Antivirus Software
• AVG Antivirus and Internet Security
• Norton Antivirus Software
• Panda Antivirus Software
Issues of antivirus:
1. Unexpected renewal costs: Some
commercial antivirus software end-
user license agreements include a
clause that the subscription will be
automatically renewed, and the
purchaser's credit card automatically
billed, at the renewal time without
explicit approval. For e.g.,
McAfee requires users to
unsubscribe at least 60 days before
the expiration of the present
subscription.
2. Rouge security applications: Some
apparent antivirus programs are
actually malware masquerading as
legitimate software, such
as WinFixer, MS Antivirus, and Mac
Defender.
3. Problems caused by false positives:
A "false positive" is when antivirus
software identifies a non-malicious
file as a virus. It can cause serious
problems. For e.g., if an antivirus
program is configured to
immediately delete or quarantine
infected files, a false positive in an
essential file can render the operating
system or some applications
unusable.
4. System and interoperability related
issues: Running multiple antivirus
programs concurrently can degrade
performance and create
conflicts. However, using a concept
called multi-scanning, several
companies (including G Data and
Microsoft) have created applications
which can run multiple engines
concurrently.
5. Effectiveness: The effectiveness of
antivirus software had decreased.
Detection rates for threats had
dropped from 40-50% in 2006 to 20-
30% in 2007. The problem is
magnified by the changing intent of
virus authors. Some years ago, it was
obvious when a virus infection was
present. The viruses of the day,
written by amateurs, exhibited
destructive behavior or pop-ups.
Modern viruses are often written by
professionals, financed by criminal
organizations.
6. New viruses: Anti-virus programs
are not always effective against new
viruses, even those that use non-
signature-based methods that should
detect new viruses.
7. Root-kits: Root-kits have full
administrative access to the
computer and are invisible to users
and hidden from the list of running
processes in the task manager. Root-
kits can modify the inner workings
of the operating system and tamper
with antivirus programs.

3. 8. Damaged files: Files which have
been damaged by computer viruses
are normally damaged beyond
recovery. Anti-virus software
removes the virus code from the file
during disinfection, but this does not
always restore the file to its
undamaged state.
9. Firmware Issues: Active anti-virus
software can interfere with
a firmware update process. Any
writeable firmware in the computer
can be infected by malicious code.
Conclusion:
Antivirus software is very useful to day-to-
day users to protect their storage devices and
computers from malware. There is much
antivirus software available in the market,
each having their own pros and cons. The
antivirus software has many issues that need
to be dealt with. Other than antivirus
software, they are many other methods
available to protect devices from external
harm such as network firewall, specialist
tool, etc.
References:
1. Antivirus Software, Wikipedia.
2. Comparison of Antivirus Software,
Wikipedia.
3. The Art of Computer Virus
Research and Defense, Peter Szor.