testssl.sh/utils/prototype.ssl2proto-check.bash
2021-06-01 14:31:31 +08:00

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#!/usr/bin/env bash
# bash socket implementation of checking the availability of SSLv2 protocol
# and ciphers on a remote server (loosely based on my bash-heartbleed implementation).
#
# Author: Dirk Wetter, GPLv2 see https://testssl.sh/LICENSE.txt
# it helps to wireshark:
# /<path>/openssl s_client -state -ssl2 -connect AA.BB.YYY.XXX:443 </dev/null
# /<path>/openssl s_client -state -debug -ssl2 -connect AA.BB.YYY.XXX:443 </dev/null
V2_HELLO_CIPHERSPEC_LENGTH=0 # initialize
IFILE=./mapping-rfc.txt
NODE=""
COL_WIDTH=32
DEBUG=${DEBUG:-0}
USLEEP_REC=${USLEEP_REC:-0.2}
USLEEP_SND=${USLEEP_SND:-0.1} # 1 second wait until otherwise specified
MAX_WAITSOCK=2
SOCK_REPLY_FILE=""
NW_STR=""
# 9 cipher specs SSLv2:
SSLv2_CIPHER_SPECS="
05 00 80
03 00 80
01 00 80
07 00 c0
08 00 80
06 00 40
04 00 80
02 00 80
00 00 00"
# SSLV2 chello:
SSLv2_CLIENT_HELLO="
,80,34 # length (here: 52)
,01 # Client Hello
,00,02 # SSLv2
,00,1b # cipher spec length (here: 27 )
,00,00 # session ID length
,00,10 # challenge length
,05,00,80 # 1st cipher
,03,00,80 # 2nd
,01,00,80 # 3rd
,07,00,c0 # 4th
,08,00,80 # 5th
,06,00,40 # 6th
,04,00,80 # 7th
,02,00,80 # 8th
,00,00,00 # 9th
,29,22,be,b3,5a,01,8b,04,fe,5f,80,03,a0,13,eb,c4 # Challenge
"
# only classical V2 ciphers are used here, see http://max.euston.net/d/tip_sslciphers.html
# there are v3 in v2!!! : https://tools.ietf.org/html/rfc6101#appendix-E
# Cipher specifications introduced in version 3.0 can be included in version 2.0 client hello messages using
# the syntax below. [..]
# V2CipherSpec (see Version 3.0 name) = { 0x00, CipherSuite }; !!!!
# see:
# http://max.euston.net/d/tip_ssldump.html
# https://idea.popcount.org/2012-06-16-dissecting-ssl-handshake/
# https://books.google.de/books?id=LfsC03f8oGsC&pg=PA592&lpg=PA592&dq=sslv2+server+hello+struct&source=bl&ots=JWeSD-9pwH&sig=lMzhxTdybJ3tfWC2p9ltIOKlIso&hl=en&sa=X&ei=U3WmVKzyNoTgOOeigNAP&ved=0CDUQ6AEwAw
help() {
echo
echo "Syntax $0 <hostname>"
echo
exit 1
}
parse_hn_port() {
PORT=443 # unless otherwise auto-determined, see below
NODE="$1"
# strip "https", supposed it was supplied additionally
echo $NODE | grep -q 'https://' && NODE=`echo $NODE | sed -e 's/https\:\/\///' `
# strip trailing urlpath
NODE=`echo $NODE | sed -e 's/\/.*$//'`
# determine port, supposed it was supplied additionally
echo $NODE | grep -q ':' && PORT=`echo $NODE | sed 's/^.*\://'` && NODE=`echo $NODE | sed
's/\:.*$//'`
}
# arg1: formatted string here in the code
code2network() {
NW_STR=`echo "$1" | sed -e 's/,/\\\x/g' | sed -e 's/# .*$//g' -e 's/ //g' -e '/^$/d' | tr -d '\n' | tr -d '\t'`
}
socksend_clienthello() {
code2network "$SSLv2_CLIENT_HELLO"
data=`echo $NW_STR`
[[ "$DEBUG" -ge 3 ]] && echo "\"$data\""
printf -- "$data" >&5 2>/dev/null &
sleep $USLEEP_SND
}
sockread_serverhello() {
[[ "x$2" = "x" ]] && maxsleep=$MAX_WAITSOCK || maxsleep=$2
ret=0
SOCK_REPLY_FILE=`mktemp /tmp/ddreply.XXXXXX` || exit 7
dd bs=$1 of=$SOCK_REPLY_FILE count=1 <&5 2>/dev/null &
pid=$!
while true; do
if ! ps ax | grep -v grep | grep -q $pid; then
break # didn't reach maxsleep yet
kill $pid >&2 2>/dev/null
fi
sleep $USLEEP_REC
maxsleep=$(($maxsleep - 1))
[[ $maxsleep -le 0 ]] && break
done
if ps ax | grep -v grep | grep -q $pid; then
# time's up and dd is still alive --> timeout
kill $pid >&2 2>/dev/null
wait $pid 2>/dev/null
ret=3 # means killed
fi
return $ret
}
display_sslv2serverhello() {
# server hello: in hex representation, see below
# byte 1+2: length of server hello 0123
# 3: 04=Handshake message, server hello 45
# 4: session id hit or not (boolean: 00=false, this 67
# is the normal case)
# 5: certificate type, 01 = x509 89
# 6+7 version (00 02 = SSLv2) 10-13
# 8+9 certificate length 14-17
# 10+11 cipher spec length 17-20
# 12+13 connection id length
# [certificate length] ==> certificate
# [cipher spec length] ==> ciphers GOOD: HERE ARE ALL CIPHERS ALREADY!
v2_hello_ascii=`hexdump -v -e '16/1 "%02X"' $1`
[[ "$DEBUG" -eq 4 ]] && echo $v2_hello_ascii # one line without any blanks
[[ -z $v2_hello_ascii ]] && return 0 # no server hello received
# now scrape two bytes out of the reply per byte
v2_hello_initbyte="${v2_hello_ascii:0:1}" # normally this belongs to the next, should be 8!
v2_hello_length="${v2_hello_ascii:1:3}" # + 0x8000 see above
v2_hello_handshake="${v2_hello_ascii:4:2}"
v2_hello_cert_length="${v2_hello_ascii:14:4}"
v2_hello_cipherspec_length="${v2_hello_ascii:18:4}"
V2_HELLO_CIPHERSPEC_LENGTH=`printf "%d\n" "0x$v2_hello_cipherspec_length"`
if [[ $v2_hello_initbyte != "8" ]] || [[ $v2_hello_handshake != "04" ]]; then
[[ $DEBUG -ge 1 ]] && echo "$v2_hello_initbyte / $v2_hello_handshake"
return 1
fi
if [[ $DEBUG -ge 2 ]]; then
echo "SSLv2 server hello length: 0x0$v2_hello_length"
echo "SSLv2 certificate length: 0x$v2_hello_cert_length"
echo "SSLv2 cipher spec length: 0x$v2_hello_cipherspec_length"
fi
return 0
}
#### main
[[ -z "$1" ]] && help # hostname
echo
parse_hn_port "$1"
if ! exec 5<> /dev/tcp/$NODE/$PORT; then
echo "`basename $0`: unable to connect to $NODE:$PORT"
exit 2
fi
# socket is now open with fd 5
[[ "$DEBUG" -ge 1 ]] && printf "sending client hello...\n\n"
socksend_clienthello
sockread_serverhello 32768 0
[[ "$DEBUG" -ge 1 ]] && printf "\nreading server hello...\n\n"
if [[ "$DEBUG" -eq 3 ]]; then
#xxd -c$COL_WIDTH $SOCK_REPLY_FILE | head -3
#hexdump -v -e '"%04_ax: " 16/1 "%02X " "\n"' $SOCK_REPLY_FILE | head -6
hexdump -C $SOCK_REPLY_FILE | head -6
echo
fi
display_sslv2serverhello "$SOCK_REPLY_FILE"
# see https://secure.wand.net.nz/trac/libprotoident/wiki/SSL
lines=`cat "$SOCK_REPLY_FILE" 2>/dev/null | hexdump -C | wc -l`
printf "Protocol: "; tput bold
if [[ "$lines" -gt 1 ]] ;then
tput setaf 1; printf "available with $(($V2_HELLO_CIPHERSPEC_LENGTH / 3 )) ciphers"
ret=0
else
tput setaf 2; printf "NOT available"
ret=1
fi
tput sgr0
[[ "$DEBUG" -ge 2 ]] && printf " ($lines lines)"
echo
# closing fd:
exec 5<&-
exec 5>&-
rm $SOCK_REPLY_FILE
echo
exit 0
#test: dragon, simhq.com=gryphon1.gryphoninternet.com misim.gov.il, shop4-heating.co.uk, service.hamburgwasser.de
# 74.116.0.167 147.237.80.2 85.92.77.27
# vim:ts=5:sw=5:expandtab
# $Id: prototype.ssl2proto-check.bash,v 1.10 2015/09/25 19:02:24 dirkw Exp $