cipherscan/cipherscan

#!/usr/bin/env bash

DOBENCHMARK=0
BENCHMARKITER=30
OPENSSLBIN="./openssl"
#OPENSSLBIN="/usr/bin/openssl"
TIMEOUT=10
CIPHERSUITE="ALL:COMPLEMENTOFALL"
TARGET=$1
VERBOSE=0
ALLCIPHERS=0
OUTPUTFORMAT="terminal"
REQUEST="GET / HTTP/1.1
Host: $TARGET
Connection: close


"


usage() {
    echo -e "usage: $0 <target:port>

$0 attempts to connect to a target site using all the ciphersuites it knowns.
Julien Vehent [:ulfr] - https://github.com/jvehent/cipherscan

example: $ $0 www.google.com:443

Use only one of the options below:
-v     increase verbosity
-a     test all known ciphers individually at the end
-json  output results in json format

OpenSSL path can be changed in the OPENSSLBIN variable
Benchmarking can be enabled in the DOBENCHMARK variable
"
    exit 1
}


verbose() {
    if [ $VERBOSE -eq 1 ];then
        echo $@
    fi
}


# Connect to a target host with the selected ciphersuite
test_cipher_on_target() {
    local sslcommand=$@
    cipher=""
    protocols=""
    pfs=""
    for tls_version in "-ssl2" "-ssl3" "-tls1" "-tls1_1" "-tls1_2"
    do
        local tmp=$(mktemp)
        $sslcommand $tls_version 1>"$tmp" 2>/dev/null << EOF
$REQUEST
EOF
        current_cipher=$(grep "New, " $tmp|awk '{print $5}')
        current_pfs=$(grep 'Server Temp Key' $tmp|awk '{print $4$5$6$7}')
        current_protocol=$(grep -E "^\s+Protocol\s+:" $tmp|awk '{print $3}')
        if [[ -z "$current_protocol" || "$current_cipher" == '(NONE)' ]]; then
            # connection failed, try again with next TLS version
            rm "$tmp"
            continue
        fi
        # connection succeeded, add TLS version to positive results
        if [ -z "$protocols" ]; then
            protocols=$current_protocol
        else
            protocols="$protocols,$current_protocol"
        fi
        cipher=$current_cipher
        pfs=$current_pfs
        # grab the cipher and PFS key size
        rm "$tmp"
    done
    # if cipher is empty, that means none of the TLS version worked with
    # the current cipher
    if [ -z "$cipher" ]; then
        verbose "handshake failed, no ciphersuite was returned"
        result='ConnectionFailure'
        return 2

    # if cipher contains NONE, the cipher wasn't accepted
    elif [ "$cipher" == '(NONE)  ' ]; then
        result="$cipher $protocols $pfs"
        verbose "handshake failed, server returned ciphersuite '$result'"
        return 1

    # the connection succeeded
    else
        result="$cipher $protocols $pfs"
        verbose "handshake succeeded, server returned ciphersuite '$result'"
        return 0
    fi
}


# Calculate the average handshake time for a specific ciphersuite
bench_cipher() {
    local ciphersuite="$1"
    local sslcommand="timeout $TIMEOUT $OPENSSLBIN s_client -connect $TARGET -cipher $ciphersuite"
    local t="$(date +%s%N)"
    verbose "Benchmarking handshake on '$TARGET' with ciphersuite '$ciphersuite'"
    for i in $(seq 1 $BENCHMARKITER); do
        $sslcommand 2>/dev/null 1>/dev/null << EOF
$REQUEST
EOF
        if [ $? -gt 0 ]; then
            break
        fi
    done
    # Time interval in nanoseconds
    local t="$(($(date +%s%N) - t))"
    verbose "Benchmarking done in $t nanoseconds"
    # Microseconds
    cipherbenchms="$((t/1000/$BENCHMARKITER))"
}


# Connect to the target and retrieve the chosen cipher
# recursively until the connection fails
get_cipher_pref() {
    [ "$OUTPUTFORMAT" == "terminal" ] && echo -n '.'
    local ciphersuite="$1"
    local sslcommand="timeout $TIMEOUT $OPENSSLBIN s_client -connect $TARGET -cipher $ciphersuite"
    verbose "Connecting to '$TARGET' with ciphersuite '$ciphersuite'"
    test_cipher_on_target "$sslcommand"
    local success=$?
    # If the connection succeeded with the current cipher, benchmark and store
    if [ $success -eq 0 ]; then
        cipherspref=("${cipherspref[@]}" "$result")
        pciph=$(echo $result|awk '{print $1}')
        get_cipher_pref "!$pciph:$ciphersuite"
        return 0
    fi
}


display_results_in_terminal() {
    # Display the results
    ctr=1
    for cipher in "${cipherspref[@]}"; do
        pciph=$(echo $cipher|awk '{print $1}')
        if [ $DOBENCHMARK -eq 1 ]; then
            bench_cipher "$pciph"
            r="$ctr $cipher $cipherbenchms"
        else
            r="$ctr $cipher"
        fi
        results=("${results[@]}" "$r")
        ctr=$((ctr+1))
    done

    if [ $DOBENCHMARK -eq 1 ]; then
        header="prio ciphersuite protocols pfs_keysize avg_handshake_microsec"
    else
        header="prio ciphersuite protocols pfs_keysize"
    fi
    ctr=0
    for result in "${results[@]}"; do
        if [ $ctr -eq 0 ]; then
            echo $header
            ctr=$((ctr+1))
        fi
        echo $result|grep -v '(NONE)'
    done|column -t
}


display_results_in_json() {
    # Display the results in json
    ctr=0
    echo -n "{\"target\":\"$TARGET\",\"date\":\"$(date -R)\",\"ciphersuite\": ["
    for cipher in "${cipherspref[@]}"; do
        [ $ctr -gt 0 ] && echo -n ','
        echo -n "{\"cipher\":\"$(echo $cipher|awk '{print $1}')\","
        echo -n "\"protocols\":[\"$(echo $cipher|awk '{print $2}'|sed 's/,/","/g')\"],"
        pfs=$(echo $cipher|awk '{print $3}')
        [ "$pfs" == "" ] && pfs="None"
        echo -n "\"pfs\":\"$pfs\"}"
        ctr=$((ctr+1))
    done
    echo ']}'
}


[[ -z $1 || "$1" == "-h" || "$1" == "--help" ]] && usage
if [ ! -z $2 ]; then
    if [ "$2" == "-v" ]; then
        VERBOSE=1
        echo "Loading $($OPENSSLBIN ciphers -v $CIPHERSUITE 2>/dev/null|grep Kx|wc -l) ciphersuites from $(echo -n $($OPENSSLBIN version 2>/dev/null))"
        $OPENSSLBIN ciphers ALL 2>/dev/null
    elif [ "$2" == "-a" ]; then
        ALLCIPHERS=1
    elif [ "$2" == "-json" ]; then
        OUTPUTFORMAT="json"
    else
        echo "ERROR: unknown option '$2'"; echo
        usage
    fi
fi

cipherspref=();
results=()

# Call to the recursive loop that retrieves the cipher preferences
get_cipher_pref $CIPHERSUITE

if [ "$OUTPUTFORMAT" == "json" ]; then
    display_results_in_json
else
    echo
    display_results_in_terminal
fi

# If asked, test every single cipher individually
if [ $ALLCIPHERS -gt 0 ]; then
    echo; echo "All accepted ciphersuites"
    for c in $($OPENSSLBIN ciphers -v ALL:COMPLEMENTOFALL 2>/dev/null |awk '{print $1}'|sort|uniq); do
        r="fail"
        osslcommand="timeout $TIMEOUT $OPENSSLBIN s_client -connect $TARGET -cipher $c"
        test_cipher_on_target "$osslcommand"
        if [ $? -eq 0 ]; then
            r="pass"
        fi
        echo "$c $r"|awk '{printf "%-35s %s\n",$1,$2}'
    done
fi