Is it safe to chmod
a directory 777, or is it a security risk?
One of my scripts requires that in order to run in multi-user situations, and I'm wondering if it's okay.
While it is generally considered to be a bad practice, because any user can remove or modify any other users data, it is not such a great risk in itself; or, better said, it all depends on the context. On a machine with a limited number of trusted users this is not really a problem, as long as the script is not world accessible (like a web cgi) or runs as root.
However, there are many ways such a need can be avoided, and if you post some details (why must the script use 777?), we can consider a better solution. One semi-solution is to set the +t bit; that way, any user can write in the directory, but only that user can then remove or modify the created files.
777
means anyone with access to the filesystem can create and execute a script. But is that exploitable to cause a security problem? Wouldn't someone with access to the filesystem be able to do that even without my 777 directory?