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Fix ticketbleed

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This commit fixes ticketbleed so that using socksend_clienthello().
can being used.

The function for retrieving the TLS session ticket is now using SNI
and it was renamed to session_ticket_from_openssl() so that this
can be used elsewhere. Also for the sake of better programming
it is using bash only.

In order to ease stripping whitespaces the bash option "extglob"
was IN GENERAL set. This should only add the possibility to do
extended pattern matching when using round brackets:

?(pattern-list)
    Matches zero or one occurrence of the given patterns.
*(pattern-list)
    Matches zero or more occurrences of the given patterns.
+(pattern-list)
    Matches one or more occurrences of the given patterns.
@(pattern-list)
    Matches one of the given patterns.
!(pattern-list)
    Matches anything except one of the given patterns.

... see bash(1). The man page though warns "separate matches against
shorter strings, or using arrays of strings instead of a single long
string, may be faster.". So when using ~100x we should do s.th. else.
It also works under bashv3.

The check_bytestream() function which was previously introduced now
also list the offending string.
This commit is contained in:
Dirk Wetter 2020-03-09 14:03:26 +01:00
parent 16be686adc
commit d1cec5ecd2
1 changed files with 45 additions and 19 deletions
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58
testssl.sh
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@ -67,6 +67,9 @@
#
#################### Stop talking, action now ####################
# This is quite handy. It enables extended pattern matching operators (see bash(1). Works also for bashv3)
shopt -s extglob
########### Definition of error codes
#
@ -10498,13 +10501,13 @@ check_bytestream() {
# first line is empty because this is a LF
:
elif [[ ${#line} -ne 4 ]] && [[ $i != 0 ]]; then
echo "length of byte $i called from $2 is not ok"
echo "length of byte $i (${line/_/}) called from $2 is not ok"
elif [[ ${line:0:1} != _ ]]; then
echo "char $i called from $2 doesn't start with a \"\\\""
echo "char $i (${line/_/}) called from $2 doesn't start with a \"\\\""
elif [[ ${line:1:1} != x ]]; then
echo "char $i called from $2 doesn't have an x in second position"
echo "char $i (${line/_/}) called from $2 doesn't have an x in second position"
elif [[ ${line:2:2} != [0-9a-fA-F][0-9a-fA-F] ]]; then
echo "byte $i called from $2 is not hex"
echo "byte $i (${line/_/}) called from $2 is not hex"
fi
i+=1
done < <( echo -e ${1//\\/\\n_})
@ -15205,17 +15208,40 @@ run_ccs_injection(){
return $ret
}
sub_session_ticket_tls() {
local sessticket_tls=""
#FIXME: we likely have done this already before (either @ run_server_defaults() or at least the output
# from a previous handshake) --> would save 1x connect. We have TLS_TICKET but not yet the ticket itself #FIXME
#ATTENTION: we DO NOT use SNI here as we assume ticketbleed is a vulnerability of the TLS stack. If we'd do SNI here, we'd also need
# it in the ClientHello of run_ticketbleed() otherwise the ticket will be different and the whole thing won't work!
# Generic function to retrieve the session ticket via openssl. It is called via run_ticketbleed() only atm.
# Return value: string with TLS session ticket
# For ticketbleed SNI would not be needed as we assume ticketbleed is a vulnerability of the TLS stack.
# However for a generic function we would need SNI
#FIXME: We should consideer to do this earlier, and save it in a global variable. It would save 1x connect.
#
sessticket_tls="$($OPENSSL s_client $(s_client_options "$BUGS $OPTIMAL_PROTO $PROXY -connect $NODEIP:$PORT") </dev/null 2>$ERRFILE | awk '/TLS session ticket:/,/^$/' | awk '!/TLS session ticket/')"
sessticket_tls="$(sed -e 's/^.* - /x/g' -e 's/ .*$//g' <<< "$sessticket_tls" | tr '\n' ',')"
sed -e 's/ /,x/g' -e 's/-/,x/g' <<< "$sessticket_tls"
session_ticket_from_openssl() {
local sessticket_tls=""
local line=""
local first=true
sessticket_tls="$($OPENSSL s_client $(s_client_options "$BUGS $OPTIMAL_PROTO $PROXY $SNI -connect $NODEIP:$PORT") </dev/null 2>$ERRFILE | awk '/TLS session ticket:/,/^$/' | awk '!/TLS session ticket/')"
# This needs to be on stderr
debugme echo "$sessticket_tls" >&2
# Now we extract the session ticket. First we'll remove the ASCII garbage (len=16chars)
# at the rhs, then we'll sqush all white spaces (normally it's just 3x " " but we're
# tolerant here. Then we remove evryth. up to the address, replace the dash in the middle.
# In the end we want commas between all bytes.
# Note the second expression requires "shopt -s extglob".
while read -r line; do
line="${line:0:$((${#line}-16))}"
line="${line%%+([[:space:]])}"
line="${line#*- }"
line="${line//-/ }"
line="${line// /,}"
if "$first"; then
# No comma in the beginning
printf "%s" "${line}"
first=false
else
printf "%s" ",${line}"
fi
done <<< "$sessticket_tls"
}
@ -15276,7 +15302,7 @@ run_ticketbleed() {
fi
debugme echo "using protocol $tls_hexcode"
session_tckt_tls="$(sub_session_ticket_tls)"
session_tckt_tls="$(session_ticket_from_openssl)"
if [[ "$session_tckt_tls" == , ]]; then
pr_svrty_best "not vulnerable (OK)"
outln ", no session tickets"
@ -15286,7 +15312,7 @@ run_ticketbleed() {
fi
len_tckt_tls=${#session_tckt_tls}
len_tckt_tls=$(( len_tckt_tls / 4))
len_tckt_tls=$(( len_tckt_tls / 3)) # Attention: this also counts commas. So we have two bytes like 32,23,
xlen_tckt_tls="$(dec02hex $len_tckt_tls)"
len_handshake_record_layer="$(( len_sid + len_ch + len_tckt_tls ))"
xlen_handshake_record_layer="$(dec04hex "$len_handshake_record_layer")"
@ -15376,7 +15402,7 @@ run_ticketbleed() {
# length of SessionTicket TLS
00, $xlen_tckt_tls ,
# data, Session Ticket
$session_tckt_tls # we have the comma already
$session_tckt_tls ,
# Extension: Heartbeat
00, 0f, 00, 01, 01"