## Documents for filesys

Code [fsys001f]

The listed file is a setuid script. On most UNIX machines, it is not possible to write a secure setuid script, due to a race condition in the Operating System. Even on systems where this is corrected, the difficulties in writing a truly secure setuid script make them very undesirable. The setuid bits should be turned off of this file.

If you must run a script under another id, then perhaps the best solution is to write a wrapper program in C which creates a safe environment for the script, then exec()'s it.

Code [fsys002w]

The listed program is a setuid executable, and it appears to contain relative pathnames (do not start with a '/'). This often represents a security hole in the program. These relative pathnames can be caused by system()* or popen()* calls which do not use full pathnames to the executable, or, on systems which support dynamic linking, relative pathnames indicating the directories containing the libraries. In any case, these need to be checked.

*Note: system() and popen() should *never* be used from a program which is executing with privileges.

Code [fsys003c]

The database of setuid programs for this platform does not exist, thus all setuid programs will be listed. When fully configured for a platform, only those setuid programs that do not appear in the distribution will be listed.

Code [fsys004i]

The listed programs are setuid, but are not in the database of setuid programs which appear in the OS distribution.

Code [fsys005a]

The listed file has an unusual filenames. These include files with multiple leading '.', filenames with spaces, etc. The variable FS_FILES can be set in the 'tigerrc' file to specify the filename patterns which are reported.

Code [fsys006a]

The listed files are device files that are located in non-standard locations. These should be checked. The variable FS_DEVDIRS can be set in the 'tigerrc' file to specify other directories which can contain device files.

Code [fsys007i]

The indicated file is a symbolic link to a system file which is related to system security. In itself, the link is not dangerous, but you should be aware of its presence, as it can cause unexpected results with the 'chown' and 'chmod' commands. On many systems, the 'chown' command does not change the owner of the link itself, but instead, changes the ownership of the file the link resolves to. The same type of problem exists for 'chmod' on most systems. Thus, the simple act of performing a

chown -R joeuser /home/joeuser

could potentially change the owner of a system file to 'joeuser'.

Code [fsys008i]

The listed directories are world writable. These provide a location for intruders to store files. They should be checked for unusual files.

Code [fsys009w]

An FSP server control file has been located. This indicates that an FSP server may be running, or have been running, using the directory containing the listed file as its base.

Code [fsys010w]

The listed file is a setgid script. On most UNIX machines, it is not possible to write a secure setgid script, due to a race condition in the Operating System. Even on systems where this is corrected, the difficulties in writing a truly secure setgid script make them very undesirable.

Code [fsys011i]

The listed programs are setgid, but are not in the database of setgid programs which appear in the OS distribution.