Networking / Beginners

Instant Messaging

As more and more people go online and more businesses and their employees rely on communicating in real time, IM has grow by leaps and bounds. IM involves using tools such as ICQ, AOL Instant Messenger (AIM),Yahoo! Messenger, Google Talk,Windows Live Messenger (aka MSN Messenger or .NET Messenger), or Windows Messenger that comes with Windows XP.This technology allows you to communicate with other members of your staff when used at work, or with friends and family when used at home. Generally, each of these IM clients tie into a service that transfers messages between other users with the same client software. However, there are programs like Trillian that allow users to consolidate their accounts on different IM networks and connect to AIM,Yahoo Messenger,Windows Live Messenger, I Seek You (ICQ), and Internet Relay Chat (IRC) all within a single interface. In recent years, such features have also been folded into other IM software, such as Windows Live Messenger supporting messages exchanged with Yahoo! Messenger clients. Despite the popularity of IM clients, many businesses prohibit the use of IM programs on network computers. One reason is practical: incessant "chatting" can become a bigger time waster than gossiping at the water fountain (and one that is less obvious for management to detect). But an even more important reason is that IM technologies pose significant security risks. Each of the messenger programs has been exploited and most of them require a patch.The hacker community has discovered exploits, which range from Denial of Service (DoS) attacks all the way to executing remote commands on a system.The following security issues that are related to using IM technology must be acknowledged:

  • IM technology is constantly exploited via buffer overflow attacks. Since the technology was made for ease of use and convenience, not for secure communications, there are many ways to exploit IM technology.
  • IP address exposure is prominent and, because an attacker can get this information from IM technology, provides a way that an attacker can isolate a user's home machine, crack into it, and then exploit it.
  • IM technology includes a file transfer capability, with some providing the ability to share folders (containing groups of files) with other users. In addition to the potential security issues of users making files available, there is the possibility that massive exploits can occur in that arena if the firewall technology is not configured to block it. All kinds of worms and viruses can be downloaded (circumventing the firewall), which could cause huge problems on an internal network.
  • Companies' Human Resources (HR) policies need to be addressed because there is no way to really track IM communication out of the box.Thus, if an employee is communicating in an improper way, it might be more difficult to prove as compared with improper use of e-mail or Web sites visited.

For companies that want to allow IM for business purposes but prevent abuse, there are software products available, such as Akonix's security gateway for public instant messaging, Zantaz's Digital Safe, and IMlogic's IM Manager, that allow companies to better control IM traffic and log and archive IM communications. Such products (combined with anti-virus software and security solutions already on a server running the IM service, and the client computer running the IM client software), add to the security of Instant Messaging.

Packet Sniffers and Instant Messaging

Packet sniffers are tools that can capture packets of data off of a network, allowing you to view its contents. A considerable amount of data can be obtained by viewing the contents of captured packets, inclusive to usernames and passwords. By using a packet sniffer to monitor IM on a network, you can view what people are chatting about and other sensitive information.

The reason packet sniffers can view IM information so easily is because the messages are passed between IM users as cleartext. Cleartext messages are transmitted without any encryption, meaning the messages being carried across a network can be easily viewed by anyone with the proper tools. Being sent as cleartext makes them as easy to view in a packet sniffer as a text message would be on your computer.

In addition to packet sniffers, there are also a number of tools specifically designed to capture IMs. For example, a program called MSN Sniffer 2 is available at EffeTech's Web site ( tool will capture any MSN chats on a local network and store them so they can be analyzed at a later time. If there is concern that information is being leaked, or policies are being broken through IM software on the network, you could use this tool to view the chats and use them as evidence for disciplinary actions or to provide to police when pressing criminal charges.

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