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The Twenty Most Critical Internet Security Holes

Ant writes: "A little over a year ago, the SANS Institute and the National Infrastructure Protection Center (NIPC) released a document summarizing the Ten Most Critical Internet Security Vulnerabilities. Thousands of organizations used that list to prioritize their efforts so they could close the most dangerous holes first. This new list, released on October 1, 2001, updates and expands the Top Ten list. With this new release, we have increased the list to the Top Twenty vulnerabilities, and we have segmented it into three categories: General Vulnerabilities, Windows Vulnerabilities, and Unix Vulnerabilities."

39 of 250 comments (clear)

  1. #21 by smnolde · · Score: 5, Funny

    Being Slashdotted

    1. Re:#21 by jd · · Score: 3, Funny

      Oh yes it is! Your site can't be broken into, if nobody can reach it. Being slashdotted is therefore a security -feature-! :)

      --
      It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
  2. Google cache mirror by Doc+Hopper · · Score: 5, Funny

    Here's Google's cache of the page. It's kind of tough to slashdot google : )
    http://www.google.com/search?q=cache:dbJlh35mihk:w ww.sans.org/top20.htm+&hl=en
    Remember, check those links, you don't want to be goatse'd....

  3. Does anyone find it scary... by Zwack · · Score: 4, Insightful

    That the top ten list of last year makes an appearance in the top 20 of this year?

    Haven't we learned anything?

    O.K. So some of them (no/weak passwords) are user related, but so many of them are admin related (bind vulnerabilities, IIS RDS vulnerabilities)

    Don't any admins care about these?

    Of course, inside a company network some of these problems can be ignored if that is the decision. R commands are useful, but I wouldn't want people using them across the internet to my machines... But at the very least firewall... Please.

    Z.

    --
    -- Under/Overrated is meta-moderation, and therefore is Redundant.
  4. people are your number 1 asset. by new-black-hand · · Score: 5, Informative

    id add

    21. Hiring admin's with no clue about security

  5. You forgot about this one by Kozz · · Score: 5, Funny

    I'm surprised to see that this hole didn't make the list.

    --
    I only post comments when someone on the internet is wrong.
  6. Re:Oxymoron by malakai · · Score: 3, Insightful

    Intuitive Linux

  7. Summary by zpengo · · Score: 3, Funny
    Top Security Vulnerabilities:
    • Clicking "Next" instead of reading.
    • Using passwords from Hackers, et al., for your system accounts.
    • Bragging about how many servers you've got running on your home computer.
    • Setting file permissions to "everyone can execute" because you can't get your Perl scripts to work.
    • Using Microsoft Anything.
    --


    Got Rhinos?
  8. Government set software standards by bark76 · · Score: 5, Interesting

    Looks like the feds are considering setting government standards, abcnews article is here. I'm not sure how helpful government standards could be, but I think I could welcome them. I'm sure that if my toaster lit on fire as often as my windows box crashes the government would do something about it, so why not hold software companies more accountable.

  9. Here's the quick list... by MadCow42 · · Score: 5, Informative
    The site is already fairly well /.'ed... Here's the top 20 holes they mention, without the detail for each point (sorry).

    "G" stands for "general holes"
    "W" stands for "Windows holes"
    "U" stands for "Unix holes"

    G1 - Default installs of operating systems and applications
    G2 - Accounts with No Passwords or Weak Passwords
    G3 - Non-existent or Incomplete Backups
    G4 - Large number of open ports
    G5 - Not filtering packets for correct incoming and outgoing addresses
    G6 - Non-existent or incomplete logging
    G7 - Vulnerable CGI Programs
    W1 - Unicode Vulnerability (Web Server Folder Traversal)
    W2 - ISAPI Extension Buffer Overflows
    W3 - IIS RDS exploit (Microsoft Remote Data Services)
    W4 - NETBIOS - unprotected Windows networking shares
    W5 - Information leakage via null session connections
    W6 - Weak hashing in SAM (LM hash)
    U1 - Buffer Overflows in RPC Services
    U2 - Sendmail Vulnerabilities
    U3 - Bind Weaknesses
    U4 - R Commands (rlogin, rsh, rcp)
    U5 - LPD (remote print protocol daemon)
    U6 - sadmind and mountd
    U7 - Default SNMP Strings

    MadCow

    --
    I used to have a sig, but I set it free and it never came back.
    1. Re:Here's the quick list... by MadCow42 · · Score: 4, Interesting

      Well, the interesting thing is the the "Windows" holes are more "bugs" than general architecture problems. Bugs can be easily fixed (if users patch their machines), and in fact most of the Windows ones already are fixed.

      The UNIX holes listed are more fundamental in nature, requiring a significant re-development effort, and in some cases, redefining of protocols and fundamental tools.

      Although the Windows "bugs" have been exploited more (and are easier to exploit in general), it'll take longer to address the issues in the UNIX list than those in the Windows list.

      Sorry... I'm not a M$ advocate, but it does point out some significant issues that we need to overcome in the UNIX world, and quickly.

      MadCow.

      --
      I used to have a sig, but I set it free and it never came back.
    2. Re:Here's the quick list... by jtdubs · · Score: 3, Insightful

      Maybe it's just me, but it seems that all of those unix holes are silly. There is absolutely NO reason for RPC, rsh/rcp, LPD, sadmin/mountd or SNMP to be open to the outside world. Just no reason for it.

      The very first thing you need for a secure network is a firewall. And not an opt-out firewall. An opt-in firewall. As follows:

      Rule #1: block in all
      Rule #2: block out all

      There, now that the firewall is secure you can add rules to it to allow the specific things you need to flow into and out of the building.

      Justin Dubs

    3. Re:Here's the quick list... by ink · · Score: 3, Interesting
      Maybe it's just me, but it seems that all of those unix holes are silly. There is absolutely NO reason for RPC, rsh/rcp, LPD, sadmin/mountd or SNMP to be open to the outside world. Just no reason for it.

      Congratulations! You've just conditioned the next wave of software developers to use port 80 for all their traffic because of your silly firewall rules. Don't believe me? Take a look at Microsoft's dotNet architecture sometime. Take a look at the IM protocols. Take a look at the new P2P protocols. What an excellent job you've done....

      Attack the source of the problem: individual computers. People like you only cause more headaches for the rest of us in the long term.

      --
      The wheel is turning, but the hamster is dead.
    4. Re:Here's the quick list... by bluebomber · · Score: 3, Informative
      At least sendmail and BIND have patches.

      You forgot the gaping hole otherwise known as the Office document format...

      What the hell are you smoking??

      Sendmail and bind can not be patched in such a way as to eventually become completely secure. The architecture underlying sendmail is not conducive to creating security. These packages should be taken out of use. There are alternatives to BIND and Sendmail: use djbdns and qmail. I haven't used djbdns, but given the quality and ease of configuration for qmail, I wouldn't hesitate to recommend anything from DJ Bernstein. See http://cr.yp.to/djbdns.html and http://cr.yp.to/qmail.html.
      It's a pity about the licensing on DJB's stuff. Otherwise I would imagine that they would be included in more distributions...

  10. Re:Most important? by GauteL · · Score: 4, Insightful

    Of course, all security holes are important.. but some are more important than others.

    1. For instance, say you run a public Webserver.. then remote root-exploits are normally more important than local root-exloits.
    2. Difficulty. If the exploit is very easy to trigger, then it's generally more important than a devilishly hard one.

    3. Widespread use. Holes that are used by every script-kiddie or worm on the Web, is generally more important than others. See 2. as well.

    4. Level of access. Exploits that lead to user-access is normally less important than exploits that lead to root-access. This is one of the advantages of most versions of UNIX/Linux vs. Windows. They are normally better at making sure services run as a less priviliged user, and not as root, thus making sure that any exploits in them do not lead to root-access... of course, there are exceptions.

  11. Re:It's not just IIS... by J4 · · Score: 3, Insightful

    It's not all about patches. Sure, it's responsible behaviour to be up to date, but it's more important to know what your machines are doing in the first place so you can take steps to
    minimize your risks up front. If you do the right thing beforehand you can have some peace of mind *before* patches get issued. Remember, exploits are around for a while before vendors get around to supplying a fix.

  12. Some bad information by D3 · · Score: 4, Insightful

    I have worked for SANS in the past but I have to disagree with the way they compiled this list. The fact that there are a larger number of "vulnerabilities" for *NIX than Windows is misleading. I just bet the M$ people latch onto this "See, Windows is less vulnerable!" Even though most of the *NIX stuff is so old you rarely find it occuring in the real world.

    What is more useful IMO is to have a ranking of these "vulnerabilities". Right now an unpatched IIS box can be hit even though you have it firewalled so only port 80 is open. With the *NIX stuff, the only way to hit a sytem via port 80 is bad CGI or a new exploit to the webserver software. And when was the last time an Apache exploit was released?

    Look at the CVE numbers. That tells a tale of what is going on _now_. The number has the year and there are many of the *NIX exploits that are 2 years old or more. Many of the Win exploits are within the last year.

    --
    Do really dense people warp space more than others?
  13. How Linux Fares by sting3r · · Score: 5, Insightful
    Many of these vulnerabilities have been addressed in the past 1-2 years by the major Linux vendors. Redhat and Debian, in particular, have been quite good at reducing the avenues of attack. For instance, the changes I've observed include:

    • Redhat used to open up the xfs port to internet traffic, but now uses a local UNIX socket. No access -> no exploit.
    • After many problems with lpd, most Linux distros now restrict the internet hosts that can connect to port 515 to localhost only.
    • I don't know of a single Linux distro that ships with default passwords for any user. (Even Solaris and the other oldskool unices stopped this practice within the past few years.)
    • With the rp_filter option, Linux (by default) drops packets that are spoofed to look like they come from a different network. For instance, traffic from the internet with your internal network's addresses in the header is automatically discarded. (FreeBSD should really do the same but they're being stubborn about it.)
    • GNU Apache and most of the distros out there remove all of the sample cgis (like nph) that used to be a security threat. Indeed, my Debian box has only the Apache manual (static html) installed; and that's damn hard to exploit. :)
    • Samba has never been vulnerable to the NETBIOS unprotected share vulnerabilities. It takes a considerable amount of effort to enable sharing anything via Samba to the general public - if you don't intend for that to happen, it's not going to happen.
    • Samba has no Null Session support. Samba does not send out lists of users (the equivalent of /etc/passwd under shadowing) like NT does. It is very difficult to break into a Linux box through SMB networking.
    • In general, setuid root programs have become setgid (something else) programs through the years. xterm and xlock immediately come to mind; on other platforms (even OpenBSD) they are still setuid root. This further hardens the GNU/Linux system. ps and netstat do not need privilege because of the privilege-bracketing nature of /proc.

    Linux boxes are much more secure than any of the competitors. Solaris is getting better; UnixWare is pretty hopeless (see BUGTRAQ). NT is ... well, draw your own conclusions about NT. I feel much safer with a Linux server than with any other OS and the security just keeps getting better.

    -sting3r

    1. Re:How Linux Fares by Mendax+Veritas · · Score: 3, Interesting
      Samba has no Null Session support. Samba does not send out lists of users (the equivalent of /etc/passwd under shadowing) like NT does. It is very difficult to break into a Linux box through SMB networking.

      This is true, but in addition to the superior security, I find that simply as a user I prefer the way Samba works. When I browse a Windows machine's list of shares, I see everything -- even shares that I'm not allowed to access. I can only find out which ones I can use by trying to access them and seeing which ones succeed. With Samba, by contrast, I find that I can only see the shares that I am allowed to access. One might say that the the signal-to-noise ratio is better with Samba, since you aren't shown things that aren't relevant to you.
    2. Re:How Linux Fares by pmz · · Score: 3, Interesting
      Linux boxes are much more secure than...

      Than what?
      OpenBSD???

      Look at the default install of OpenBSD, and you'll find most of the "Top 20" are already addressed. Linux is generally very good, but I wouldn't put the default install of RedHat between my business and the world. It's just too risky.

  14. Until companies treat computer security SERIOUSLY by ghibli · · Score: 3, Insightful

    Until managers understand and treat computer security SERIOUSLY, the same basic weaknesses will remain.

    One thing that helps is for companies to hire computer security specialists, and make this their primary job. Instead, many businesses that I work with expect their already-overburdened sysadmin or network administrator to "protect" the network, something he/she has never been trained to do. The average NT Administrator does NOT know much about network security. The new Win2K Security certification is a step in the right direction, but it is only a baby step.

    -------------
    "Against stupidity the gods themselves content in vain." - Schiller

  15. Re:Biggest Vulnerability... by Quasar1999 · · Score: 3, Insightful

    Nah, I say non computer literate users... that is the biggest risk...

    Think of the chaos one could start by simply emailing everyone instructions on how to 'protect your system', while in reality sending instructions on how to disable their firewalls... The amount of people that would fall for it would be insane!

    No, I say the biggest vulnerability is lack of knowledge and ignorance.

    --

    ---
    Programming is like sex... Make one mistake and support it the rest of your life.
  16. The Value of This by maggard · · Score: 3, Insightful
    This document is a great one to give to the Powers-That-Be at one's employer, school, ISP, etc.

    In one credible place with annotations and links are the most common problems. Sure most of them aren't news to /.'ers but they're likely news to lots of other folks and exactly the thing to light a fire under the PHB's of the world. It's almost a checklist of "Are these implemented and if not *why* not?"-items for the semi-technical and as such is invaluable.

    My thanks to the SANS Institute and the NIPC for releasing such a well-written & useful document.

    --
    I don't read ACs: If a post isn't worth so much as a nom de plume to its author then I wont bother either.
  17. Re:Biggest Vulnerability... by Winged+Cat · · Score: 3, Interesting

    Nah, I say non computer literate users... that is the biggest risk...

    Agreed. Many (most?) of the "incompetent admins" are, in fact, home computer users who have no idea they've become admins simply by taking responsibility for their own computer. I wonder if a PSA warning people about this, and instructing them on "what you can do to fight cyberterrorism" (I hate that term, but it pulls the right heart strings just now), would cause a good percent of the vulnerable systems to get patched.

  18. SNMP exploit is UNDERRATED! by jgaynor · · Score: 3, Informative

    Maybe not on UNIX machines, where SNMP is generally turned off by default - but on Cisco devices where it is enabled by default with the common SNMP names . . .

    SNMP on cisco devices is weak because of the default community string names (public, private and secret). To add to the situation, the secret string will allow you to bring interfaces up and down at will, all without a trace of intrusion in the logs. While the big guys like ATT and Wcom may fix these using default config files, may universities and smaller carriers dont even know it exists.

  19. Linux not the most secure.... by MosesJones · · Score: 4, Insightful

    The most secure system is a Unix box run by a 40+ year old bloke who has seen the virtual deaths of more script kiddies than I've had hot dinners.

    Actually Mainframe admins run pretty tight ships as well. Its a sad reflection on the new generation of admins that most of these are things the old school had never even thought of doing wrong. The current raft of virii are an example. The people hit had new school systems, the old school companies survived untouched.

    Old blokes in a distant room of the organisation, possibly called "Gary" or "Dave" never seem to be doing much, but their network never fails.

    --
    An Eye for an Eye will make the whole world blind - Gandhi
    1. Re:Linux not the most secure.... by Anonymous Coward · · Score: 3, Interesting

      The most secure system is a Unix box run by a 40+ year old bloke who has seen the virtual deaths of more script kiddies than I've had hot dinners.

      Thats me. 40+, and always losing jobs to script kiddies turned sysadmins who underbid the job by several orders of magnitude. That means I get the jobs with clued bosses :-) That also means the other sites get r00ted immediately after the skriptadmin leaves.

      I lost a bid a few weeks ago to secure a big network in the midst of a complete rebuild. My bid was around 400 hours to do the work, plus 200 hours testing and fixing, using expensive cisco and nokia hardware. The guy who got the contract claimed he could do it in only 3 days onsite with a single linux box.

      He left after a week, after he managed to trash the network, and left the whole thing open to the internet over the weekend. CodeRed, nimda, and every box sploited, anon FTP server full of porn, etc. They arent paying him. They cant even find him to prosecute.

      They called me monday morning, and my price doubled from the original estimate, and they have no choice but to pay. This will make for a nice month long vacation at the end, a sunny beach or maybe a skiing holiday.

      Cant use my nic from this secure location. awwww.

  20. New easy way to make sure W2K/IIS is patched. by NineNine · · Score: 4, Informative
  21. The 5 most common reasons for security problems by Nicolas+MONNET · · Score: 5, Informative

    ... in programs (setting aside administration issues such as passwords)

    1. string.h
    2. sprintf
    3. system
    4. char buff[255];
    5. snprintf(buf,len,user_input);

    Let's face it, C's string handling is the biggest cause of security problems on the Internet. Static strings are evil. Too bad there is no standard way to handle them in C.

    1. Re:The 5 most common reasons for security problems by dvdeug · · Score: 3, Insightful

      > This is like banning hammers just because people have been known to hit their thumbs with them.

      This is like banning unguarded circular saws just because people have been known to slice off their thumbs with them. Guess what? Circular saws come with guards. If a tool is really dangerous, and can be made safer through simple solutions, then we use those solutions to make it safer.

      Strings are a source of problems for a lot of programs, including well-known programs that have very experianced programmers working on them. Unit testing will never catch all bugs. Many languages - Ada/Java/C++/Perl - have string types that won't cause buffer overflows - ever. Using an unsafe tool when you have a safe tool at hand that will do the job about as easily is just stupid, whether or not you think you're good enough to keep yourself safe.

  22. The really interesting part of that list... by devphil · · Score: 5, Insightful


    ...is that, for the Unix vulnerabilities, most of them have long since been replaced by better, more secure alternatives. Where I work, nobody has used the word "telnet" or "rexec" for years. Nobody here runs sendmail, or sadmind, or SNMP stuff. It's basically a list of "don't ever use this ancient crap" tools.

    But for the Windows vulnerabilities, they're all related to current, recent, flagship, "this is what you should be using" products. No alternatives within the Windows world.

    --
    You cannot apply a technological solution to a sociological problem. (Edwards' Law)
  23. G4 - Large number of open ports by ink · · Score: 5, Insightful
    It's very very dangerous to keep on complaining about having a "large" number of open ports. Many system administrators will take this to mean "firewall all these ports at the border".

    "Why is that dangerous?" I hear you ask? As we drive more and more traffic to a small number of ports (read: everything on port 80) because of draconian firewall and proxy servers, and even driving all traffic to one protocol (read: http) a large number of services will still be running, but will now be undetectable without traffic analysis, which is mostly voodoo technology right now. The bugs and security holes are still there, but now they are hidden from us because we've conditioned everyone that non-80 is firewalled (see SOAP and Microsoft's dotNET -- in order to avoid firewalling, they are basically going to do RPC over port 80 using HTTP!)

    I agree that unused services need to be shut down, but at the source of the problem and not at the firewall. We need to encourage new protocols to make use of new ports so that we can manage thus stuff -- the more we drive traffic away, the harder our job will be. Please, if you are in charge of a firewall, take time to think about what you are doing to everyone else when you institute strict policies that only make you safer in the very short term. Not only are you hurting yourself, but you're giving your users and network a false sense of security.

    Besides, the attacks de jour of late have all propogated over SMTP and HTTP, haven't they?

    --
    The wheel is turning, but the hamster is dead.
  24. Re:Good Points, But Nothing Really New by sulli · · Score: 3, Insightful

    They don't have to be new. The lesson of code red and nimda is that many, many servers aren't properly maintained. Sometimes a refresher course on the basics is just what the doctor ordered.

    --

    sulli
    RTFJ.
  25. Consumers cannot fix these problems by nuetrino · · Score: 3, Informative
    When one looks at the top six vulnerabilities, one sees the mark of shoddy implementation and almost nonexistent manufacturer and vendor responsibility. For instance, the default installs of OSs that leave the customer at risk. An example of this is in the Windows and MacOs install. In the installation process, there is a suggestion to make a shared folder. Most people do not need a shared folder, and with the explosion of broadband, most people should not have a shared folder. Yet both these applications want the user to create one. To make matter worse, there is no suggested password to increase the likelihood of security(On an up note, I was happy to see that SuSE did suggest a password at installation). Software vendors should not be encouraging us to make our computers less secure.

    Equally negligent are broadband vendors that give away connection hardware, but can't be bothered to include a firewall or software that will check for open ports. These vendors won't make the simplest effort to insure the product they are selling is secure, yet will not take the responsibility when their service dies due to DOS attacks. These DOS attacks are largely possible because of the massive number of wide-open computers created by their broadband connections.

    This is not a rant; this is a statement of reality. Vendors can not, and should not, expect the consumer to be skilled enough to provide adequate levels of security. This is why houses and cars come with locks. Sometimes consumers lock themselves out, but that is a minor inconvenience. As an extreme example, many shoes now have Velcro, and most cars, at least in the U.S., have automatic transmissions.

    No stream of security patches, warnings, and news items will solve the problem. The consumer is not skilled enough to keep up. Until the default configuration is secure, until vendors are forced to take monetary consequences for their defective products, and until the consumer is trained to suffer the imposed inconveniences, we will continue to see the same sort of problems.

  26. Re:obsession with security ridiculous? NO!!! by CodeShark · · Score: 4, Informative
    I hope you were being sarcastic, but if not and for any body else who might not understand, here's my list of reasons why a high degree of focus on security is not ridiculous, but mandatory:
    • DDOS attacks, etc. that use your machine to do the dirty work,
    • Net worms which may be propagated from an insecure machine
    • back doors: perhaps you will do something useful, valuable, or important on your computer in the future, only to get clobbered or ripped off by whoever's bug installed the backdoor, not to mention the loss of your time to recover your valuable work (if you even can) or to reinstall and reformat.
    • remote keyboard monitors... first time you use your credit card to make an online purchase, and bam, script kiddie has your cc # and can attempt to use it or sell it to even less scrupulous folks,
    • and my personal favorite reason: to make it less worth the script kiddies time to try to take down yours, mine, and everybody else's machines for kicks and giggles. Think about the bragging rights between "hey my new ultra-virus took down four machines, or "hey, my new ultra-virus took down 200,000 machines..."

      Course, if those four machines were the front end machines for M$, that might be worth a brag or two ;-)

    But let me offer a different perspective. What if the security holes in your machine allowed big gov't, or someone else to snoop on what you were doing online all the time? Would you think about closing the security holes in your machine then?
    --
    ...Open Source isn't the only answer -- but it's almost always a better value than the alternatives...
  27. Missed one: Cross Site Scripting by slashkitty · · Score: 3, Informative
    This one affects most every site, including ones like chase, citibank, aol, slashdot, nytimes and many more. It's cross platform and their is not an easy patch. I wouldn't be surprised if there were already malicious undetected scripts that could pretty much get your logins to all your favorite sites.

    A year and a half old advisory, and sites still refuse to fix it. http://www.cert.org/advisories/CA-2000-02.html

    Some of you will remember the problems with Hotmail relating to cross site scripting. Newsflash, it affects your site too!

    --
    -- these are only opinions and they might not be mine.
  28. Re:Good Points, But Nothing Really New by Arandir · · Score: 3, Interesting

    The trouble is that most Linux distros come with NFS, BIND, Sendmail and rlogin/rsh installed by default. They're getting a bit more savvy about this, but it's still a major problem. If you're a competent administrator, you can deal with it. Most people aren't. I certainly am not, which is why I prefer systems that don't turn on every damned vulnerability known to man.

    Too many distros want to make you do all of your sysadmining from DistroConf2. You don't tune your automobile engine from your dashboard, and you don't secure your system from a GUI.

    --
    A Government Is a Body of People, Usually Notably Ungoverned
  29. Dammit, How many times do I have to say this? by trcooper · · Score: 5, Insightful


    Linux boxes are much more secure than any of the competitors. Solaris is getting better; UnixWare is pretty hopeless (see BUGTRAQ). NT is ... well, draw your own conclusions about NT. I feel much safer with a Linux server than with any other OS and the security just keeps getting better.


    Bullshit. You're lying to yourself. One OS is not automatically more secure than another. Notice the first problem they noted: Default installations of operating systems and applications. They meant all operating systems, they didn't say 'RedHat and Debian are pretty good, you'll probably be okay with them, or at least more okay than someone using Windows.' Not only is this the most important point of the article, all other vulnerabilities stem from it. They all exist because of complacency with the current state of security of a system.

    Security is not determined by OS. Period.

    A systems security depends on the administrator's vigilance in keeping up to date on patches. Sure, windows has had a lot of exploits lately, but how many of these exploits were not patchable? Hmm. Conversly, Linux and other Unix systems have been not as widely or at least as publically attacked lately. Is this because they have less holes? Redhat 7.1, about 6 months old has 23 security alerts listed. 7.0 and 6.2 both have over 60. So, there's likely likely more out there in 7.1. Many of these are critical and involve remote root exploits. Feel safe? I hope not.

    (Li||U)nix can be attacked with the same efficiency of what we've seen happen to Windows systems in the past few months. Administrators aren't simply better because they admin unix boxes, that's proven in the article that 50% of the copies of BIND that were running in mid 1999 were vulnerable. It would make sense that a similar percentage of other security risks exist as well.

    I'm not bashing Unix, and I'm certainly not saying that Windows is a more secure OS. Its a moot point. What I'm saying is that people who blame the OS for their mistakes are wrong. They're using windows as a scapegoat, and ignoring the real problem behind this.

    Unix will be hit by one of these sometime or another, and it will be just as publicized because it will likely use the same distrubution methods as before, email.

    Go back, read the article again, paying close attention to the generic problems they mention. These are the basic things that any admin has to look at, every day. A machine is never secure. You can be sure of that.

  30. SANS' suggested filtering rules in ipchains by ajs · · Score: 3, Informative

    MY_NET=1.2.3.4/5
    INT_DEV=eth0
    EXT_DEV=eth1
    # 1. Any packet coming into your network must not have a source address of your internal network
    ipchains -A forward -i $EXT_DEV -j DENY -s $MY_NET
    # 2. Any packet coming into your network must have a destination address of your internal network
    ipchains -A forward -i $EXT_DEV -j DENY -d ! $MY_NET
    # 3. Any packet leaving your network must have a source address of your internal network
    ipchains -A forward -i $INT_DEV -j DENY -s ! $MY_NET
    # 4. Any packet leaving your network must not have a destination address of your internal network.
    ipchains -A forward -i $INT_DEV -j DENY -d ! $MY_NET
    # 5. Any packet coming into your network or leaving your network must not have a source or destination address of a private address or an address listed in RFC1918 reserved space. These include 10.x.x.x/8, 172.16.x.x/12 or 192.168.x.x/16 and the loopback network 127.0.0.0/8.
    ipchains -A forward -i $EXT_DEV -j DENY -s 10.0.0.0/8
    ipchains -A forward -i $EXT_DEV -j DENY -s 172.16.0.0/12
    ipchains -A forward -i $EXT_DEV -j DENY -s 192.168.0.0/16
    ipchains -A forward -j DENY -d 10.0.0.0/8
    ipchains -A forward -j DENY -d 172.16.0.0/12
    ipchains -A forward -j DENY -d 192.168.0.0/16
    ### REMOVE the next 3 rules for masquerading systems
    ipchains -A forward -i $INT_DEV -j DENY -s 10.0.0.0/8
    ipchains -A forward -i $INT_DEV -j DENY -s 172.16.0.0/12
    ipchains -A forward -i $INT_DEV -j DENY -s 192.168.0.0/16
    # 6. Block any source routed packets or any packets with the IP options field set.

    # This is done at the kernel level under Linux, and is usually set by default.