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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN"><HTML><HEAD> <TITLE>Maximum Security -- Ch 4 -- Just Who Can Be Hacked, Anyway?</TITLE></HEAD><BODY TEXT="#000000" BGCOLOR="#FFFFFF"><CENTER><H1><IMG SRC="../button/samsnet.gif" WIDTH="171" HEIGHT="66" ALIGN="BOTTOM" BORDER="0"><BR><FONT COLOR="#000077">Maximum Security: </FONT></H1></CENTER><CENTER><H2><FONT COLOR="#000077">A Hacker's Guide to Protecting Your Internet Site and Network</FONT></H2></CENTER><CENTER><P><A HREF="../ch03/ch03.htm"><IMG SRC="../button/previous.gif" WIDTH="128" HEIGHT="28"ALIGN="BOTTOM" ALT="Previous chapter" BORDER="0"></A><A HREF="../ch05/ch05.htm"><IMGSRC="../button/next.gif" WIDTH="128" HEIGHT="28" ALIGN="BOTTOM" ALT="Next chapter"BORDER="0"></A><A HREF="../index.htm"><IMG SRC="../button/contents.gif" WIDTH="128"HEIGHT="28" ALIGN="BOTTOM" ALT="Contents" BORDER="0"></A> <HR></CENTER><CENTER><H1><FONT COLOR="#000077">4</FONT></H1></CENTER><CENTER><H1><FONT COLOR="#000077">Just Who Can Be Hacked, Anyway?</FONT></H1></CENTER><P>The Internet was born in 1969. Almost immediately after the network was established,researchers were confronted with a disturbing fact: The Internet was not secure andcould easily be cracked. Today, writers try to minimize this fact, reminding youthat the security technologies of the time were primitive. This has little bearing.Today, security technology is quite complex and the Internet is still easily cracked.</P><P>I would like to return to those early days of the Internet. Not only will thisgive you a flavor of the time, it will demonstrate an important point: The Internetis no more secure today than it was twenty years ago.</P><P>My evidence begins with a document: a <I>Request for Comments</I>, or <I>RFC</I>.Before you review the document, let me explain what the RFC system is about. Thisis important because I refer to many RFC documents throughout this book.<H2><FONT COLOR="#000077"><B>The Request For Comments (RFC) System</B></FONT></H2><P>Requests for Comments (RFC) documents are special. They are written (and postedto the Net) by individuals engaged in the development or maintenance of the Internet.RFC documents serve the important purpose of requesting Internet-wide comments onnew or developing technology. Most often, RFC documents contain proposed standards.</P><P>The RFC system is one of evolution. The author of an RFC posts the document tothe Internet, proposing a standard that he or she would like to see adopted network-wide.The author then waits for feedback from other sources. The document (after more comments/changeshave been made) goes to draft or directly to Internet standard status. Comments andchanges are made by working groups of the Internet Engineering Task Force (IETF).<BLOCKQUOTE> <P><HR><FONT COLOR="#000077"><B>Cross Reference:</B></FONT><B> </B>The Internet Engineering Task Force (IETF) is "... a large, open, international community of network designers, operators, vendors, and researchers concerned with the evolution of the Internet architecture and the smooth operation of the Internet." To learn more about the IETF, go to its home page at <A HREF="http://www.ietf.cnri.reston.va.us/"><B>http://www.ietf.cnri.reston.va.us/</B></A>. <HR></BLOCKQUOTE><P>RFC documents are numbered sequentially (the higher the number, the more recentthe document) and are distributed at various servers on the Internet.<BLOCKQUOTE> <P><HR><FONT COLOR="#000077"><B>Cross Reference:</B></FONT><B> </B>One central server from which to retrieve RFC documents is at <A HREF="http://ds0.internic.net/ds/dspg0intdoc.html"><B>http://ds0.internic.net/ds/dspg0intdoc.html</B></A>. This address (URL) is located at InterNIC, or the <I>Network Information Center</I>. <HR></BLOCKQUOTE><H3><FONT COLOR="#000077"><B>InterNIC</B></FONT></H3><P>InterNIC provides comprehensive databases on networking information. These databasescontain the larger portion of collected knowledge on the design and scope of theInternet. Some of those databases include<UL> <LI>The WHOIS Database--This database contains all the names and network numbers of hosts (or machines) permanently connected to the Internet in the United States (except <TT>*.mil</TT> addresses, which must be obtained at <TT>nic.ddn.mil</TT>).<BR> <BR> <LI>The Directory of Directories--This is a massive listing of nearly all resources on the Internet, broken into categories.<BR> <BR> <LI>The RFC Index--This is a collection of all RFC documents.</UL><BLOCKQUOTE> <P><HR><FONT COLOR="#000077"><B>Cross Reference:</B></FONT><B> </B>All these documents are centrally available at <A HREF="http://rs.internic.net"><B>http://rs.internic.net</B></A>. <HR></BLOCKQUOTE><H2><FONT COLOR="#000077"><B>A Holiday Message</B></FONT></H2><P>As I mentioned earlier, I refer here to an early RFC. The document in questionis RFC 602: <I>The Stockings Were Hung by the Chimney with Care</I>. RFC 602 wasposted by Bob Metcalfe in December, 1973. The subject matter concerned weak passwords.In it, Metcalfe writes: The ARPA Computer Network is susceptible to security violationsfor at least the three following reasons:<DL> <DD><B>1. </B>Individual sites, used to physical limitations on machine access, have not yet taken sufficient precautions toward securing their systems against unauthorized remote use. For example, many people still use passwords which are easy to guess: their fist [sic] names, their initials, their host name spelled backwards, a string of characters which are easy to type in sequence (such as <TT>ZXCVBNM</TT>).<BR> <BR> <B>2. </B>The TIP allows access to the ARPANET to a much wider audience than is thought or intended. TIP phone numbers are posted, like those scribbled hastily on the walls of phone booths and men's rooms. The TIP required no user identification before giving service. Thus, many people, including those who used to spend their time ripping off Ma Bell, get access to our stockings in a most anonymous way.<BR> <BR> <B>3. </B>There is lingering affection for the challenge of breaking someone's system. This affection lingers despite the fact that everyone knows that it's easy to break systems, even easier to crash them.</DL><P>All of this would be quite humorous and cause for raucous eye winking and elbownudging, if it weren't for the fact that in recent weeks at least two major servinghosts were crashed under suspicious circumstances by people who knew what they wererisking; on yet a third system, the system wheel password was compromised--by twohigh school students in Los Angeles no less. We suspect that the number of dangeroussecurity violations is larger than any of us know is growing. You are advised notto sit "in hope that Saint Nicholas would soon be there." That documentwas posted well over 20 years ago. Naturally, this password problem is no longeran issue. Or is it? Examine this excerpt from a Defense Data Network Security Bulletin,written in 1993:<DL> <DD>Host Administrators must assure that passwords are kept secret by their users. Host Administrators must also assure that passwords are robust enough to thwart exhaustive attack by password cracking mechanisms, changed periodically and that password files are adequately protected. Passwords should be changed at least annually.</DL><P>Take notice. In the more than 25 years of the Internet's existence, it has neverbeen secure. That's a fact. Later in this book, I will try to explain why. For now,however, I confine our inquiry to a narrow question: <I>Just who can be cracked?</I></P><P>The short answer is this: As long as a person maintains a connection to the Internet(permanent or otherwise), he or she can be cracked. Before treating this subjectin depth, however, I want to define <I>cracked</I>.<H2><FONT COLOR="#000077"><B>What Is Meant by the Term <I>Cracked</I>?</B></FONT></H2><P>For our purposes, <I>cracked</I> refers to that condition in which the victimnetwork has suffered an unauthorized intrusion. There are various degrees of thiscondition, each of which is discussed at length within this book. Here, I offer afew examples of this <I>cracked</I> condition:<UL> <LI>The intruder gains access and nothing more (<I>access</I> being defined as simple entry; entry that is unauthorized on a network that requires--at a minimum--a login and password).<BR> <BR> <LI>The intruder gains access and destroys, corrupts, or otherwise alters data.<BR> <BR> <LI>The intruder gains access and seizes control of a compartmentalized portion of the system or the whole system, perhaps denying access even to privileged users.<BR> <BR> <LI>The intruder does NOT gain access, but instead implements malicious procedures that cause that network to fail, reboot, hang, or otherwise manifest an inoperable condition, either permanently or temporarily.</UL><P>To be fair, modern security techniques have made cracking more difficult. However,the gorge between the word <I>difficult</I> and the word <I>impossible</I> is wideindeed. Today, crackers have access to (and often study religiously) a wealth ofsecurity information, much of which is freely available on the Internet. The balanceof knowledge between these individuals and bona-fide security specialists is notgreatly disproportionate. In fact, that gap is closing each day.</P><P>The purpose of this chapter is to show you that cracking is a common activity:so common that assurances from <I>anyone</I> that the Internet is secure should beviewed with extreme suspicion. To drive that point home, I will begin with governmentalentities. After all, defense and intelligence agencies form the basis of our nationalsecurity infrastructure. They, more than any other group, must be secure.<H2><FONT COLOR="#000077"><B>Government</B></FONT></H2><P>Throughout the Internet's history, government sites have been popular targetsamong crackers. This is due primarily to press coverage that follows such an event.Crackers enjoy any media attention they can get. Hence, their philosophy is generallythis: If you're going to crack a site, crack one that <I>matters</I>.</P><P>Are crackers making headway in compromising our nation's most secure networks?Absolutely. To find evidence that government systems are susceptible to attack, oneneedn't look far. A recent report filed by the Government Accounting Office (GAO)concerning the security of the nation's defense networks concluded that:<DL> <DD>Defense may have been attacked as many as 250,000 times last year...In addition, in testing its systems, DISA attacks and successfully penetrates Defense systems 65 percent of the time. According to Defense officials, attackers have obtained and corrupted sensitive information--they have stolen, modified, and destroyed both data and software. They have installed unwanted files and "back doors" which circumvent normal system protection and allow attackers unauthorized access in the future. They have shut down and crashed entire systems and networks, denying service to users who depend on automated systems to help meet critical missions. Numerous Defense functions have been adversely affected, including weapons and supercomputer research, logistics, finance, procurement, personnel management, military health, and payroll.<FONT SIZE="2"><SUP>1</SUP></FONT></DL><BLOCKQUOTE> <P><HR><FONT SIZE="2"><SUP>1</SUP></FONT><I>Information Security: Computer Attacks at Department of Defense Pose Increasing Risks</I> (Chapter Report, 05/22/96, GAO/AIMD-96-84); Chapter 0:3.2, Paragraph 1. <HR></BLOCKQUOTE><DL> <DD></DL><BLOCKQUOTE> <P><HR><FONT COLOR="#000077"><B>Cross Reference:</B></FONT><B> </B><I>Information Security: Computer Attacks at Department of Defense Pose Increasing Risks</I> is available online at<TT> </TT><A HREF="http://www.securitymanagement.com/library/000215.html"><B>http://www.securitymanagement.com/library/000215.html</B></A>. <HR></BLOCKQUOTE><P>That same report revealed that although more than one quarter of a million attacksoccur annually, only 1 in 500 attacks are actually detected and reported. (Note thatthese sites are defense oriented and therefore implement more stringent securitypolicies than many commercial sites. Many government sites employ secure operatingsystems that also feature advanced, proprietary security utilities.)</P><P>Government agencies, mindful of the public confidence, understandably try to minimizethese issues. But some of the incidents are difficult to obscure. For example, in1994, crackers gained carte-blanche access to a weapons-research laboratory in Rome,New York. Over a two-day period, the crackers downloaded vital national securityinformation, including wartime- communication protocols.</P><P>Such information is extremely sensitive and, if used improperly, could jeopardizethe lives of American service personnel. If crackers with relatively modest equipmentcan access such information, hostile foreign governments (with ample computing power)could access even more.⌨️ 快捷键说明
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