[Freeswitch-users] TLS SIP packet tracing and visualization

[Giovanni Maruzzelli]

Hello fellows,

after some experimentation with various tools, I come out with a little
shell tool that maybe can be useful to you too.

It can only work with non-forward secrecy ciphers, obviously, and only if
is started before the client do the initial TLS handshake (eg, just restart
the client). Forward secrecy cannot be decrypted after fact, so don't waste
effort.

An example of ciphers that can be decrypted are the "AES256-SHA" openssl
cipher group. You can use ssldump to check what cipher is used by
serverhello.

Enjoy, make it better, and share it :)


#!/bin/bash
# brought to you by Giovanni Maruzzelli
#
SERVERIP="192.168.1.150"
SERVERPORT="5061"
PRIVKEY="/etc/certs/privkey.pem"
STDERR2DEVNULL=" 2>/dev/null "
REGEX="notyet"

if [ -z "$1" ]; then
        REGEX="\\\.*"
else
        REGEX="$1"
fi
FILTER="ssl.app_data and sip matches"
FILTER2="$FILTER \"$REGEX\""
FILTER3="'$FILTER2'"
ARGUMENT="-i 1 -Y $FILTER3 -E header=y -T fields -e frame.number -e
frame.time -e frame.time_delta_displayed -e ip.src -e ip.dst -e
sip.Status-Line -e sip.Request-Line -e sip.msg_hdr -l -d
tcp.port\=\=5061,sip  -o \"ssl.keys_list:
$SERVERIP,$SERVERPORT,sip,$PRIVKEY\" $STDERR2DEVNULL | sed -u 's/\t/\n/g' |
sed -u '/^$/d' | sed -u 's/^[0-9]*$/\n==&==============================/g'"

echo ""
echo "NB: if it do not works, edit script so that STDERR2DEVNULL=\" \" and
try again"
echo ""
echo "NB: remember to quote and escape match patterns, using triple slash"
echo "    eg, for matching 1010 at pbx.example.com, use \"1010 at pbx.example.com
\""
echo "    eg, for matching anything, use \"\\\\\\.*\""
echo "    eg, for matching *98, use \"\\\\\\*98\""
echo "USAGE: $0 \"\\\\\\*98 at pbx.example.com\""
echo ""


case "$1" in
        -help|--help|?)
        exit 0
        ;;
*)
        echo "THIS TIME WE'RE DOING:"
        echo "tshark $ARGUMENT"
        echo ""
        bash -c "tshark $ARGUMENT"
        ;;
esac



-- 

Sincerely,

Giovanni Maruzzelli
OpenTelecom.IT
cell: +39 347 266 56 18
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