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| I crashed the school server |
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Avenger
Member #4,550
April 2004
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Thats right, I were reading in this topic how to crash Linux. I then wanted to test this on a computer on my school, where every single computer is running linux, from a main server (silly way of doing it, if you ask me::)). So I created a file named 'fork.c' on my account, ran 'gcc' (it suprises me that my school even has that kind of programs:)), and 'link'ed it. I now executed './fork.exe', it now slowly created thousands of threads/processes, until it hang. To begin with I thought it only crashed the computer I were on, but I soon realized that I managed to kill off all the school computers. I should never have done this:-/ EDIT: Will this be a fatal error, or does one just have to restart the server?:-[
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HoHo
Member #4,534
April 2004
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I guess simple restart shoud help, at least in theory __________ |
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ReyBrujo
Moderator
January 2001
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If it is a new distribution with a good file system, it might be able to recover after a check. If it is an old distribution or if it is using ext2, I would pray. -- |
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Tobias Dammers
Member #2,604
August 2002
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Yeah, unless you have managed to insert fork.exe into the boot sequence (which on a sanely configured linux system a restricted user could not do), it should be fine. --- |
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Avenger
Member #4,550
April 2004
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AFAIK, they have updated not long ago (KDE 2.4, 3.2 or something)
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LordChaos
Member #5,750
April 2005
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Linux in school? Be happy. In my class, nobody knows that there are other OSes. Actually, they don't know that there are other browsers than Internet Explorer... LordChaos |
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Archon
Member #4,195
January 2004
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Quote: Don't like lessons in the computer room because of that.
That'd be fun because then you'd totally show them up |
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LordChaos
Member #5,750
April 2005
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If you tell them that you do a litte game which has not Doom3 graphics and sound quality it's very uninteresting for them. And of course, there is the rule: "Programming can not be hard. Maybe, when I do a second Far Cry, it costs me 10 years, but in some way, I'll tackle it." You can feel very sad if someone want to show off because he knows how to install a game ("Path? What the hell is that? You don't need that for installing a game, trust me." LordChaos |
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Steve Terry
Member #1,989
March 2002
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You just better pray nobody finds out it was you. We were explicitly warned agressively at my Uni that if we ever set off a fork bomb knowingly or otherwise they would ban us from the CS department. Really made those multithreaded assignemnts all the more "fun" knowing you had to be really really careful. BTW fork bombs are more or less script kiddie nonsense, someone finds out how to do it then wants to "show off", it's not really impressive of someone. ___________________________________ |
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Avenger
Member #4,550
April 2004
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I have already set up to talk with the computer teacher/manager/expert on our school:-/
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Simon Parzer
Member #3,330
March 2003
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I've once had a problem similar like yours. I flooded the server (Win2k server) with net broadcasts using a simple batch file: @echo off :send net send * -some stupid text- >NUL GOTO send
Although the server didn't crash and I quitted the dos box after a few seconds, our sys admin wasn't very happy about it |
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kazzmir
Member #1,786
December 2001
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I did the fork bomb "trick" on our main solaris server a few years ago.. the thing grinded to a halt but luckily after pressing ctrl-C for about 5 minutes the program stopped. I think Solaris handles a bajillion processes better than linux, but maybe thats changing.. i dunno. |
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HoHo
Member #4,534
April 2004
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Once long time ago when I thought myself as a QB guru I created a "virus". All it did was to print out some text and check if autoexec.bat has the path for executing the virus. Since I couldn't test it I simply assumed it was correct and working(I knew I was perfect Next day when I went to school teacher asked me to start the infected computer. All I could see was the text message printed all over the screen in a infinite loop. Problem was that qb's file and string manipulation functions sucked heavily and it couldn't test correctly if the path was there or not. So, every time it executed it added its own execution path to autoexec.bat. After the virus had finished wit thet autoexec continued running and next thing it executed was the virus. Nothing could kill it and I had to use a boot floppy to repair now ~10MB autoexec.bat file That's the story of my first and only "virus" I've written. A bit OT now. A friend of mine once wanted to test QB's file writing. He created a program that wrote lines of a-letters in a file. The program ran for a couple of hours and generated ~1.5GB file. Then he zipped it down to ~100kB, copied to floppy and distributed as a game he had created. Most of them soon came back complaining that it takes so long to unpack that or it didn't fit on their HD The same friend also tried to write data with the same program to floppy drive. After running ~3h it had created ~100kB text file __________ |
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Kris Allen
Member #4,639
May 2004
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Why do people take enjoyment in crashing school / college computers? What if 100s of students failed their courses because you were fucking around with the system, and they lose hours of work? - Kris |
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Avenger
Member #4,550
April 2004
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I have already said I regret that I did it:-/ (even if you werent talking to me:P)
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enric
Member #4,016
November 2003
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Hi, sorry to have caused you a bit of trouble. (hope it's only a bit I am still asking myself why the distributor or the system-admin of a school server wouldn't set a limit to the processes normal users can start (and keep a reasonable number of pids for root). The concept of a safe multiuser environment is: root can break (and repair) everything. Users can't break nothing but their home directory. Isn't it? So, instead of shouting "DON't DO FORK BOMBS KIDS!!!", they should simply set a limit IMHO "they" = distributor or system-admin ______________________________________________________ |
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Steve Terry
Member #1,989
March 2002
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"they"==lazy ___________________________________ |
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HoHo
Member #4,534
April 2004
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I read some discussion somewhere about limiting creating processes and I think the reason why there is no limit is that it makes system little bit slower because it has to check if the user actually is allowed to create the process in the first place so to make system a bit faster it's turned off by default. __________ |
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Kanzure
Member #3,669
July 2003
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Oooh, story time. Let's all tell about the times we abused the school network. That "net send" is evil; It's caused a lot of trouble in my school. The superintendent does not want to get a message saying "stupid loser", apparently. (Although that one wasn't mine, previous ones were, and that stirred the birds in the nest office, resulting in some commotion to have a nice long chat with me.) "Mister Anderson.. we see here that you are living two lives. In one, you are the grade A student, Bryan. In the other, you are the computer ..hacker. One of these has to go." I was thinking, "Hm, this sounds familiar," the whole time. I had to write a paper on what I did, how to fix what I did, and suggestions to correct the network. What I did that was "wrong" was pretty much take for granted the lack of security. For example, when a student didn't log off, I would go to their networked hard drive and change permissions through an EASILY ACCESSIBLE MENU to allow me full read/write control, other times I'd search through the list of student ID numbers to find the ID numbers of certain last names, also the whole "net send thing", registry editing (to get past Internet security), etc. Of course, I shouldn't have done any of it, but I was just curious. When you tell somebody to not do something, and you leave it easily accessible to that person, well.. yeah. |
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ReyBrujo
Moderator
January 2001
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Quote: I am still asking myself why the distributor or the system-admin of a school server wouldn't set a limit to the processes normal users can start (and keep a reasonable number of pids for root). The concept of a safe multiuser environment is: root can break (and repair) everything. Users can't break nothing but their home directory. Isn't it? The difference between a hacker and a cracker is that a hacker would tell the system administrator that it is possible for the system to crash doing something, and warn him to check if he had updated the configuration to prevent that, and that the cracker would just execute the program. Who said the administrator knows every single hole the system has? If you know something, you should warn him that something bad might happen. You can then do a proof of concept for him to see, but never try it out in the system knowing that, if it is unpatched, it might crash something. That is like saying "Well, I brought this virus that deleted the BIOS of every computer in the network to try it out. I thought your antivirus would caught it, but it didn't. Your fault for not having a better antivirus software". -- |
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Samuel Henderson
Member #3,757
August 2003
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We had fun playing with the "shutdown -i" in highschool. Not really hacking or anything of the sort... just an annoyance. ================================================= |
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BAF
Member #2,981
December 2002
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heh. I had fun at public school (now im in a private school and basically run the network for them Made a bat file with hundreds of net send * HAHAHA commands.... ran it a bunch. Everyone got hundreds of windows, and i got in a lot of trouble. My account was locked out except for on a couple certain computers. They checked the gb of files in my accounts directory ont he server, and found my send bombs... well, that wasnt all of what got me locked to another computer. In a stroke of geniusness, i took a screenshot on my computer. They forced a desktop background from the main server. I poked around some, found the server and saw it wasn't protected from write access. So (to minimize damage, i copied the old file so they could back it up) I put my own screenshot int here. Everyone was like WTF, their 1337 win2k IT staff tracked it down to the computer i was on at the time, so they locked me out. Sent a letter home, etc. I basically laughed at them and told them tehy needed to secure their network some more. They didn't like that too much |
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Billybob
Member #3,136
January 2003
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Kiddies. Time to whip out some Gentoo forum search action!! :() { :|: & } ; : How to secure system: Quote: i would reccomend everyone reading this thread to set a line like this in /etc/security/limits.conf Might want to change 10... And one last fork bomb
Tasty. Like many kids I have unfortunantly attacked public school computers.
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Derezo
Member #1,666
April 2001
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Quote: The difference between a hacker and a cracker.... I consider a "Hacker" to be someone who can use tools (on a computer in this case) in a useful manner for something they weren't intended for. For example, using MS Paint to crash someone's computer. A cracker is someone who can use their knowledge in cryptography to "crack" a security barrier. As a simple example, finding an encrytption key through the use of logical patterns. Hackers aren't necessarily nicer or meaner than crackers, there are good and bad versions of each. It's all in the person. As for the whole school computers thing, I am SICK OF THOSE DAMN THINGS. I don't even use them directly anymore. I remote desktop into another workstation and use that. I'll put up with an 800ms delay in my typing if it means I can type in an editor that isn't Corel Word Perfect. Recently they crossed the line. (..had to vent, sorry "He who controls the stuffing controls the Universe" |
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CGamesPlay
Member #2,559
July 2002
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I hack for my own purposes. Installing putty.exe named "Remote Terminal Connection" in my start menu/programs/accessories/communications folder so I can program from school. Plus the fact tat I'm running privoxy, so I can ssh tunnel to it and get to the internet without the filtering. -- Ryan Patterson - <http://cgamesplay.com/> |
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because it can easily happen unintentionally to make a "fork bomb" when somebody is experimenting with new programming techniques.
Just goes to show you that school admins need to be on the ball, cause punk kids will be, well, punk kids.