Bugtraq mailing list archives
Re: Security Problem ftpd (includes wu.ftpd 2.4 and 2.4.2 beta 4)
From: jseng () stf org sg (James Seng)
Date: Thu, 13 Jul 1995 00:43:17 +0800
On Wed, 12 Jul 1995, Henri Karrenbeld wrote:
l-wx------ 1 <yourname> 64 Jul 12 13:07 5 -> [0301]:24718
[snip]
So normal access for wtmp is 644, however this 'hard link' into the filesystem points directly to the inode (24718) and gives you write access to this file by writing to /proc/2728/fd/5 instead of to /var/adm/wtmp.
Just like to ask a stupid question. Is "5 -> [0301]:24718" a hard link or is it a soft link? (sorry..i dont have the spec for /proc filesystem..) If it is a soft link, then it is no bug. The soft link maybe own you you but this doesnt means that inode 24718 is own by you. The ftp daemon may continue to access /var/adm/utmp even though it has euid itself to <yourname> since it has open() the file while it is still root. If it is a hard link, then we are in deep trouble. If i am not wrong, /proc/<processid>/exe is also a link which actually points to the inode of the program of the process. This means that anyone can overwrite or modify any program they run by 1. run the program and then suspend it 2. ps and look for process id 3. Overwrite /proc/<processid>/exe with their trojan version. I maybe wrong about the whole thing however...feel free to correct me. -James Seng
Current thread:
- Jul 9 08:06:03 all inetd[122]: httpd/tcp server failing, (continued)
- Jul 9 08:06:03 all inetd[122]: httpd/tcp server failing Dr. Frederick B. Cohen (Jul 09)
- Re: Jul 9 08:06:03 all inetd[122]: httpd/tcp server failing Darren Reed (Jul 09)
- updated-secure-w#-daemons Dr. Frederick B. Cohen (Jul 09)
- Re: Jul 9 08:06:03 all inetd[122]: httpd/tcp server failing Kent Fitch (Jul 09)
- Re: Jul 9 08:06:03 all inetd[122]: httpd/tcp server failing Casper Dik (Jul 10)
- Re: Jul 9 08:06:03 all inetd[122]: httpd/tcp server failing Ken Wilcox (Jul 11)
- Exploit+fix for Linux SIGURG Marek Michalkiewicz (Jul 11)
- The FTP Bounce Attack *Hobbit* (Jul 11)
- Security Problem ftpd (includes wu.ftpd 2.4 and 2.4.2 beta 4) Henri Karrenbeld (Jul 12)
- Re: Security Problem ftpd (includes wu.ftpd 2.4 and 2.4.2 beta 4) Marek Michalkiewicz (Jul 12)
- Re: Security Problem ftpd (includes wu.ftpd 2.4 and 2.4.2 beta 4) James Seng (Jul 12)
- Re: Security Problem ftpd (includes wu.ftpd 2.4 and 2.4.2 beta 4) Henri Karrenbeld (Jul 12)
- Re: Security Problem ftpd (includes wu.ftpd 2.4 and 2.4.2 beta 4) Aleph One (Jul 13)
- Re: Security Problem ftpd (includes wu.ftpd 2.4 and 2.4.2 beta 4) Jeremy Fitzhardinge (Jul 13)
- Re: Security Problem ftpd (includes wu.ftpd 2.4 and 2.4.2 beta 4) James W. Abendschan (Jul 12)
- Re: Security Problem ftpd (includes wu.ftpd 2.4 and 2.4.2 beta 4) Lyndon Nerenberg (Jul 12)
- Re: Security Problem ftpd (includes wu.ftpd 2.4 and 2.4.2 beta 4) Aleph One (Jul 13)
- Re: Jul 9 08:06:03 all inetd[122]: httpd/tcp server failing Karl Strickland (Jul 10)
- Re: Jul 9 08:06:03 all inetd[122]: httpd/tcp server failing Perry E. Metzger (Jul 10)
- Re: Jul 9 08:06:03 all inetd[122]: httpd/tcp server failing BioH (Jul 10)
- Re: Exploit for Linux wu.ftpd hole Nathan Lawson (Jul 09)