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Symantec
has come out with an on-line animated report for your convenience.
For direct access to the latest reports, please click
here. In the overall scheme of things, there is not a lot you can do to prevent bots being unleashed, You can keep your defenses up by making sure you have the latest virus and operating system updates plus a top quality Internet Security package on your system with a two way firewall
Example: Emerging Threat: Bot-infected computers
Bots
are programs that are covertly installed on a user’s machine in order to allow an unauthorized user to control the computer remotely
through a communication channel such as IRC. These channels allow the
remote attacker to control a large number of compromised computers
over a single, reliable channel in a bot network, which can then be
used to launch coordinated attacks.
Bots
allow for a wide range of functionality and most can be updated to
assume new functionality by downloading new code and features. Bots
can be used by external attackers to perform DoS attacks against an
organization’s Web site. Furthermore, bots within an organization’s network can be used to attack other organizations’ Web sites, which can have serious business and legal consequences.
Bots can
be used by attackers to harvest confidential information from compromised
computers, which can lead to identity theft. Bots can also be used
to distribute spam and phishing attacks, as well as spyware, adware,
and misleading applications.
Between
July 1 and December 31, 2008, Symantec observed an average of 63,912
active bot-infected computers per day. This is an 11 percent increase
over the previous six-month period. Furthermore, Symantec observed
6,049,594 distinct bot-infected computers during the current reporting
period, a 29 percent increase from the previous period. This increase
is largely driven by a peak in bot activity in September when a number
of vulnerabilities were disclosed that were actively exploited by bots.
Command-and-control
servers are computers that bot network owners use to relay commands
to bot-infected computers on their networks.
In the last six months
of 2006, Symantec identified 4,746 bot command-and-control servers,
a 25 percent decrease from the first six months of 2008. A
drop in the number of command-and-control servers combined with a rise
in the number of bot-infected computers indicates that, on average,
bot networks are increasing in size. Bot networks are thus becoming
more consolidated. Consolidated bot networks will likely mean that
organizations will have to deal with a well entrenched, experienced,
and dedicated group of bot network owners instead of a population of
hobby hackers. It
could also signal a fundamental change in the way bots communicate
with one another.
Symantec has seen bots that are structured on a peer-to-peer
model, in which the machines connect together rather than connecting
to a central command-and-control server.
Symantec has also observed
that command-and-control servers are beginning to adopt encryption,
so that they are less visible. China
had the highest number of bot-infected computers during the second
half of 2006, accounting for 26 percent of the worldwide total. This
is an increase of six percentage points over the previous six months.
This increase was driven by a rise in the number of bots in the country
rather than a decrease in other countries. This coincides with and
illustrates a trend that Symantec first discussed in 2005, in which
bot activity in China appeared to be increasing. During the second
half of 2006, the United States had the second highest number of bot-infected
computers, accounting for 14 percent of the worldwide total. The
United States was the site of 40 percent of all known command-and-control
servers, making it the highest ranked country in this category. The
high proportion of command-and-control servers likely indicates that
servers in the United States control not only bot networks within the
country but offshore as well.
Organizations
should monitor all network-connected computers for signs of bot infection,
ensuring that any infections are detected and isolated as soon as possible.
They should also ensure that all antivirus definitions are updated
regularly.
As compromised computers can be a threat to other systems,
Symantec also recommends that the enterprises notify their ISPs of
any potentially malicious activity. Creating and enforcing policies
that identify and limit applications that can access the network may
also be helpful in limiting the spread of bot infections. To
prevent bot infections, Symantec recommends that ISPs perform both
ingress and egress filtering to block known bot traffic. ISPs should
also filter out potentially malicious email attachments to reduce exposure
to enterprises and end users.End
users should employ defense-in-depth strategies, including the deployment
of antivirus software and a firewall. They should update antivirus
definitions regularly and ensure that all desktop, laptop, and server
computers are updated with all necessary security patches from their
operating system vendor. Symantec also advises that users never view,
open, or execute any email attachments unless the attachment is expected
and comes from a known and trusted source, and unless the purpose of
the attachment is known.
View the latest- complete Symantec Internet Security
Threat reports. See more info on privacy computer safety and network protection software.
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