Focus on Software

nmap, Nessus, Saint and more.

Most of you are likely running the new Linux kernel. Whether from your favorite distribution or downloaded from the Web, this will seem like a small transition compared to what's coming. As I write, I am testing the new Caldera OpenLinux 2.2 beta. This distribution comes with not only a new kernel, but a new glibc as well—yes, a new system library. By publication time, I'm sure other distributions will be offering glibc-2.1, and I'll have heard much wailing and gnashing of teeth.

Several distributions, including Red Hat and Debian, have already included glibc distributions, based on glibc-2.0.7. As I remember, the glibc-2.0.x libraries were marked “experimental”, so if you experimented, oh well. You say Red Hat didn't mention the glibc library included in 5.x was experimental? I guess we all need to pay closer attention to those small details.

The new glibc-2.1 is different, and in some cases, incompatible. After installing the beta, I attempted to build ssh with no luck. A function call by needed ssh was missing. Also, my 128-bit encryption glibc Netscape binary wouldn't start—I had to install the libc5 binary of Netscape. These things should be fixed by the final release. This month, I'm still building with glibc-2.0.7.

nmap: http://www.insecure.org/nmap/index.html

nmap is a utility for mapping your network and open ports on the network. It is a very powerful, flexible, security auditing tool. While nmap has a number of legitimate uses, many options are available to perform “stealthy” probes of networks, something of questionable value. This tool will almost certainly become a favorite of “script kiddies” everywhere, so scanning your own network in advance to learn what they'll find will save you some headaches. At least, it will if you use the information to close/monitor any open holes that were found. Several of nmap's options appear to be aimed at not triggering monitoring tools like courtney to report attacks. As a network and systems administrator, I consider probes of my systems and networks to be overtly hostile acts. At best, they will gain you a message to your zone technical contact; at worst, an entry in the hosts.deny file, sendmail access.db reject list and an ipchains drop packet entry. I know I'm not alone. Required libraries are libnsl and glibc.

Nessus: http://www.nessus.org/

Nessus is a highly configurable and very powerful security auditing tool. Like nmap, it will probe your network, looking for holes. Unlike nmap, Nessus requires a graphical interface, but provides a slightly more user-friendly report. You'll need to supply a bit more information to start it up, as it works in a server/client configuration. Nessus is also less subject to being “hijacked” by non-privileged users. If nmap is on your system in an accessible place, anyone can run it. Since the Nessus client must connect to a Nessus server and the server is password protected, ordinary users cannot make use of it as easily. You can make it even more secure by not leaving the server running. Required libraries are libX11, libXext, libXi, glibc, libdl, libgdk, libglib, libgmp2, libgtk, libm, libnsl and libresolv.

Saint: http://www.wwdsi.com/saint/

Saint is the reincarnation of SATAN. This particular tool will be comfortable to those who have used SATAN, but the license agreement bears reading. Based on the wording, I'd say their definition of “commercial” is significantly different from most definitions. The agreement appears to be more anti-litigation than restrictive of the use of the software. Still, it is a good tool. It requires the Perl 5 library and a web browser.

nettest: http://zorro.pangea.ca/~renec/nettest.php3

nettest is a fairly simple and extremely useful Perl script that will monitor any number of hosts for connectivity. It won't watch individual processes, but it will ping the host at designated intervals. If it notices a particular host has stopped responding (for whatever reason), it will take some action. That action may be no more than logging the event in syslog or e-mailing one or more addresses. If you know Perl, you can make it do even more. nettest can also be configured to take the same action when connectivity is restored. It requires the Perl library.

xfreecell: http://www2.giganet.net/~nakayama/

Freecell has been one of my favorite games for as long as I can remember. The addicting part of this game is that you know it's theoretically possible to win every game; however, I've yet to see anyone do it. While my average stays fairly high, occasionally I outsmart myself and just can't win—that doesn't stop me from trying. Fast animations give hours of fun. Required libraries are Xext, X11, stdc++, libm and glibc.

Ted: http://www.nllgg.nl/Ted/

Finally—a text editor that uses RTF (Rich Text Format) as its default format. This editor is a nice, very simple text processor. It will read ASCII text and RTF formatted files and write RTF, ASCII and HTML. I didn't test the HTML feature. I was mainly interested in the fact that it handles RTF, the one format any true word processor will understand. Spelling modules are available for Ted in English (American and British), Dutch, German, French, Spanish and Portuguese. Required libraries are glibc, libtiff, libjpeg, libpng and libgif.

David A. Bandel (dbandel@ix.netcom.com) is a Computer Network Consultant specializing in Linux. When he's not working, he can be found hacking his own system or enjoying the view of Seattle from an airplane.

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