Security Basics mailing list archives
Re: Creating file on login
From: Brad Arlt <arlt () cpsc ucalgary ca>
Date: Thu, 27 Nov 2003 10:56:08 -0700
On Thu, Nov 27, 2003 at 08:34:46AM -0300, Fausto wrote:
I have a system that when one try to login it create a file with the name of the user that tried to log. The problem is that if the do not exists the system creates the file with the invalid user... Can we do some exploit in this case...?? Is this problem dangerous...
I am not sure an exploit is possible or practical. A login name of /etc/passwd or ../../../../../../passwd may not yield desirable results. And there is of course the simple (and possible) DoS on your filesystem where one just trys to login using random strings in an attempt to use all inodes on the filesystem (or disk space, whichever really...) A single log file, using XML or other easily parsible tagging system will yield the same result without the problems from above. Or you could just sanitize usernames before using them as a filename - sanitizing user input before you use it is always a good idea. ----------------------------------------------------------------------- __o Bradley Arlt Security Team Lead _ \<_ arlt () cpsc ucalgary ca University Of Calgary (_)/(_) Joyously Canadian Computer Science --------------------------------------------------------------------------- ----------------------------------------------------------------------------
Current thread:
- Creating file on login Fausto (Nov 27)
- Re: Creating file on login Brad Arlt (Nov 27)
- Re: Creating file on login Vishal (Nov 27)