Re: Safe Mode

On Sun, 2002-05-12 at 22:46, Ilia A. wrote: > > However, quite frankly, this is a lame attack, because all it will do is > > consume file descriptors for only the CHILD process the script is > > running in. The script will then hit the fd limit of the child process > > (most systems around 255 is the default) This will not hurt the process, > > because all needed file descriptors were opened before the script was > > executed. The beauty of this is that the kernel will the reject all > > future calls beyond the limit, which halts i/o usage, and causes the > > process to consume more user time, which cause the process to hit max > > execution limit. > > While the file description attack may be "lame" as you call it and won't cause > excessive harm. There are many other ways that 2-3 lines a webserver can be > brought down to its knees. If you want I can post code for A LOT more potent > attacks that will disable the webserver. I simply choose not to because I > believe that disclosing such information will do more harm then good. > Even the "lame" file descriptor attack can be made very dangerous by adding of > 1 line of code. > Really, what is that line? I would take a bet that it probably has nothing to do with safe mode, and would work regardless of it being in the language.. I will also take a bet that there is another security measure in php that can be used against it. > > The argument you make to remove safe mode because it is not perfect is > > unfounded. By the same argument you could say we shouldn't use locks on > > our doors, because hey "they can be picked". > > > > Safe mode is not only imperfect it does not even work properly. In the last > day and a half I've showed 5 bugs that allow it be bypassed, simply take a > look at the latest safe_mode bugs. Five, I only saw one. Regardless they can and should be fixed. > Some of those were fixed other were not as > yet. To continue with your lock analogy, you do not protect your house with a > broken lock, because beyond cosmetic value it does absolutely nothing. If the lock is broken, you fix it, you don't get rid of the lock altogether > > Ilia -Jason