Instant Messaging

One alternative to the asynchronous form of communication of email is the growing use of instant messaging (IM) software solutions, such as the MSN Messenger, ICQ, and AOL Instant Messenger products that link to a central server when the software is opened and provide a continuously available means of communications with other users of the same system. Also, file-sharing solutions that use both client/server and peer-to-peer network connectivity (such as the Napster and Gnutella products that have been the subject of many items of legislation recently) are included in this category.

Instant messaging solutions pose many of the same vulnerabilities as email, in that they are readily accessible to a broad audience and may receive a high volume of spam, hoaxes , and unwanted viral programs. In addition, IM communications are sent in cleartext by default. This leaves the communications vulnerable to packet sniffing. Another potential hazard of IM is the fact that many IM clients now include file-transfer capabilities. Because the IM client application might not integrate strongly with the operating system, file-transfer capabilities could be used to transmit viral agents that bypass some forms of antivirus protection.

Because some file-sharing systems only advertise the platform-independent short name form of a file's name , which specifies only an eight-character filename and a three-character file extension (often written as 8.3 naming ), it is possible to receive and automatically process improperly named executable files that perform unexpected and often undesirable actions.

Open file shares inadvertently advertised by file-sharing systems can generate a tremendous load on the network bandwidth used by others connecting to the shared system, potentially exposing many forms of sensitive information. Additionally, because many IM clients transmit data in plaintext, user conversations along with any sensitive information transferred can be sniffed and later used for nefarious purposes.