Legislation introduced in 2002 would even allow copyright holders to
launch attacks against users of these file-sharing networks who are suspected of
making protected content available publicly, without threat of legal action. The
bill, the P2P Piracy Prevention Act (H.R. 5211), introduced by Howard Berman,
D-California (www.house.gov/berman), would exempt copyright holders and the
organizations that represent them from prosecution if they were to disable or
otherwise impair a peer-to-peer network. The only way to undermine a true peer-
to-peer network is to disrupt the peers themselves—even if they happen to be
living on your corporate network.
Although the earliest popular file-sharing applications limited the types
of files they would carry, newer systems make no such distinction, and permit
sharing of any file, including hostile code. The Kournikova virus reminded
system administrators how social engineering can impact corporate security, but
who can guess what form the next serious security outbreak would take?
Solving The Problem
Unfortunately, there is no silver bullet to eliminate the risks posed by the services
described in the preceding section. Virus scanners, both server- and client-level,
and an effective signature update scheme goes a long way towards minimizing
the introduction of malicious code, but anti-virus software protects only against
known threats, and even then only when the code is either self-propagating or so
commonly deployed that customers have demanded detection for it. I have been
present on conference calls where virus scanner product managers were
providing reasons why Trojans, if not self-propagating, are not “viruses” and are
therefore outside the realm of virus defense.
As more and more of these applications become proxy-aware, and
developers harness local networking libraries to afford themselves the same
preconfigured network access available to installed browser services, it should
become clear to administrators that the reactive techniques provided by anti-virus
software are ineffective. To fully protect the enterprise, these threats must be
stopped before they can enter. This means stopping them at the various external
access points.
Content filters are now a necessity for corporate computing
environments. Although many complaints have been lodged against filter
vendors over the years (for failing to disclose filter lists, or over-aggressive
filtering), the benefits of outsourcing your content filtering efforts far outweigh
the potential failings of an in-house system. One need only look at the
proliferation of Web-mail providers to recognize that managing filter lists is a
monumental task. Although early filtering devices incurred a substantial
performance hit from the burden of comparing URLs to the massive databases of
inappropriate content, most commercial proxy vendors have now established
partnerships with content filtering firms to minimize the performance impact.
Quite frequently in a large organization, one or more departments will
request exception from content filtering, for business reasons. Legal departments,
Human Resources, Information Technology, and even Research and
Development groups can often have legitimate reasons for accessing content that
filters block. If this is the case in your organization, configure these users for an
alternate, unfiltered proxy that uses authentication. Many proxies are available
today that can integrate into established authentication schemes, and as described
in the “Who, What, Where? The Case for Authentication and Logging” section
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