diff --git a/doc/testssl.1 b/doc/testssl.1 index 66ac0ac..c6c3bea 100644 --- a/doc/testssl.1 +++ b/doc/testssl.1 @@ -385,7 +385,7 @@ Security headers (X\-Frame\-Options, X\-XSS\-Protection, Expect\-CT,\.\.\. , CSP \fB\-L, \-\-lucky13\fR Checks for LUCKY13 vulnerability\. It checks for the presence of CBC ciphers in TLS versions 1\.0 \- 1\.2\. . .P -\fB\-WS, \-\-winshock\fR Checks for Winshock vulnerability\. It tests for absence of GCM ciphers which were introduced in the fix and correlates that with the server banner\. +\fB\-WS, \-\-winshock\fR Checks for Winshock vulnerability\. It tests for the absence of a lot of ciphers, some TLS extensions and ec curves which were introduced later in Windows\. In the end the server banner is being looked at\. . .P \fB\-4, \-\-rc4, \-\-appelbaum\fR Checks which RC4 stream ciphers are being offered\. diff --git a/doc/testssl.1.html b/doc/testssl.1.html index c299029..0ab379a 100644 --- a/doc/testssl.1.html +++ b/doc/testssl.1.html @@ -340,7 +340,7 @@ Also for multiple server certificates are being checked for as well as for the c

-L, --lucky13 Checks for LUCKY13 vulnerability. It checks for the presence of CBC ciphers in TLS versions 1.0 - 1.2.

-

-WS, --winshock Checks for Winshock vulnerability. It tests for absence of GCM ciphers which were introduced in the fix and correlates that with the server banner.

+

-WS, --winshock Checks for Winshock vulnerability. It tests for the absence of a lot of ciphers, some TLS extensions and ec curves which were introduced later in Windows. In the end the server banner is being looked at.

-4, --rc4, --appelbaum Checks which RC4 stream ciphers are being offered.

diff --git a/doc/testssl.1.md b/doc/testssl.1.md index 73341d3..e9012bf 100644 --- a/doc/testssl.1.md +++ b/doc/testssl.1.md @@ -254,7 +254,7 @@ Also for multiple server certificates are being checked for as well as for the c `-L, --lucky13` Checks for LUCKY13 vulnerability. It checks for the presence of CBC ciphers in TLS versions 1.0 - 1.2. -`-WS, --winshock` Checks for Winshock vulnerability. It tests for absence of GCM ciphers which were introduced in the fix and correlates that with the server banner. +`-WS, --winshock` Checks for Winshock vulnerability. It tests for the absence of a lot of ciphers, some TLS extensions and ec curves which were introduced later in Windows. In the end the server banner is being looked at. `-4, --rc4, --appelbaum` Checks which RC4 stream ciphers are being offered. diff --git a/testssl.sh b/testssl.sh index 164c2ba..b102f48 100755 --- a/testssl.sh +++ b/testssl.sh @@ -759,6 +759,10 @@ debugme() { [[ "$DEBUG" -ge 2 ]] && "$@" return 0 } +debugme1() { + [[ "$DEBUG" -ge 1 ]] && "$@" + return 0 +} hex2dec() { echo $((16#$1)) @@ -7436,9 +7440,14 @@ determine_tls_extensions() { [[ $success -eq 0 ]] && extract_new_tls_extensions $TMPFILE tmpfile_handle ${FUNCNAME[0]}.txt fi + + # Keep it "on file" for debugging purposes + debugme1 safe_echo "$TLS_EXTENSIONS" >"$TEMPDIR/$NODE.$NODEIP.tls_extensions.txt" + return $success } + extract_certificates() { local version="$1" local savedir @@ -10150,6 +10159,8 @@ run_fs() { fi CURVES_OFFERED="$curves_offered" CURVES_OFFERED=$(strip_trailing_space "$CURVES_OFFERED") + # Keep it "on file" for debugging purposes + debugme1 safe_echo "$CURVES_OFFERED" >"$TEMPDIR/$NODE.$NODEIP.curves_offered.txt" # find out what groups are supported. if "$using_sockets" && ( "$fs_tls13_offered" || "$ffdhe_offered" ); then @@ -13333,6 +13344,7 @@ parse_tls_serverhello() { [[ $DEBUG -ge 1 ]] && tmpfile_handle ${FUNCNAME[0]}.txt return 1 fi + # https://www.iana.org/assignments/tls-extensiontype-values/tls-extensiontype-values.xhtml case $extension_type in 0000) tls_extensions+="TLS server extension \"server name\" (id=0), len=$extension_len\n" ;; 0001) tls_extensions+="TLS server extension \"max fragment length\" (id=1), len=$extension_len\n" ;; @@ -17441,26 +17453,33 @@ run_beast(){ # This vulnerability affected all SChannel services -- most notably RDP (port 3398 normally). See # https://support.microsoft.com/en-us/help/2992611/ms14-066-vulnerability-in-schannel-could-allow-remote-code-execution-n # and http://www.securitysift.com/exploiting-ms14-066-cve-2014-6321-aka-winshock for "exploiting"/crashing lsass.exe. +# What we do here is giving a strong hint. # -# What we do here is giving a hint, as with the Rollup patch MS introduced later is to supply the additional ciphers +# First we check whether TLS 1.3 is available. Then with the fix MS introduced came additional ciphers # TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 TLS_DHE_RSA_WITH_AES_128_GCM_SHA256 TLS_RSA_WITH_AES_256_GCM_SHA384 TLS_RSA_WITH_AES_128_GCM_SHA256 # = DHE-RSA-AES256-GCM-SHA384 DHE-RSA-AES128-GCM-SHA256 AES256-GCM-SHA384 AES128-GCM-SHA256. -# We check for those (in sockets only to avoid overhead) and for port 443 we also grab the server banner to be more sure. -# Also we check whether TLS 1.3 is available and some ciphers (ARIA, CCM, CAMELLIA and CHACHAPOLY). Those ciphers could -# also be retrieved from our array TLS_CIPHER_RFC_NAME[i] and using TLS_CIPHER_HEXCODE[i]. The latter will be done later. +# We also check for the absence of ciphers which came in way later (ECDHE-RSA-AES128-GCM-SHA256 / ECDHE-RSA-AES256-GCM-SHA384), or +# more ciphers like ARIA, CCM, CAMELLIA and CHACHAPOLY. (Those ciphers could also be retrieved from our array TLS_CIPHER_RFC_NAME[i] +# and using TLS_CIPHER_HEXCODE[i]. We may want to # do that later. We check for all this in sockets only to avoid overhead.) +# Then we check for absence of elliptical curves and TLS extensions. +# That all should minimize false # positives because of middle boxes, proxies and later Windows versions. +# The last straw then is to check for webserver banners (http.sys, IIS/8.0 and IIS/8.5). # run_winshock() { - local ws_ciphers_hex='00,9F, 00,9D, 00,9E, 00,9C' + local wsfixed_ciphers='00,9F, 00,9D, 00,9E, 00,9C' local aria_ciphers='C0,3D,C0,3F,C0,41,C0,43,C0,45,C0,47,C0,49,C0,4B,C0,4D,C0,4F,C0,51,C0,53,C0,55,C0,57,C0,59,C0,5B,C0,5D,C0,5F,C0,61,C0,63,C0,65,C0,67,C0,69,C0,6B,C0,6D,C0,6F,C0,71,C0,3C,C0,3E,C0,40,C0,42,C0,44,C0,46,C0,48,C0,4A,C0,4C,C0,4E,C0,50,C0,52,C0,54,C0,56,C0,58,C0,5A,C0,5C,C0,5E,C0,60,C0,62,C0,64,C0,66,C0,68,C0,6A,C0,6C,C0,6E,C0,70' local camellia_ciphers='C0,9B,C0,99,C0,97,C0,95,C0,77,C0,73,00,C4,00,C3,00,C2,00,C1,00,88,00,87,00,86,00,85,00,C5,00,89,C0,79,C0,75,00,C0,00,84,C0,7B,C0,7D,C0,7F,C0,81,C0,83,C0,85,C0,87,C0,89,C0,8B,C0,8D,C0,8F,C0,91,C0,93,C0,76,C0,72,00,BE,00,BD,00,BC,00,BB,00,45,00,44,00,43,00,42,00,BF,00,46,C0,78,C0,74,00,BA,00,41,C0,9A,C0,98,C0,96,C0,94,C0,7A,C0,7C,C0,7E,C0,80,C0,82,C0,84,C0,86,C0,88,C0,8A,C0,8C,C0,8E,C0,90,C0,92' local chacha_ccm_ciphers='CC,14,CC,13,CC,15,CC,A9,CC,A8,CC,AA,C0,AF,C0,AD,C0,A3,C0,9F,CC,AE,CC,AD,CC,AC,C0,AB,C0,A7,C0,A1,C0,9D,CC,AB,C0,A9,C0,A5,16,B7,16,B8,13,04,13,05,C0,AE,C0,AC,C0,A2,C0,9E,C0,AA,C0,A6,C0,A0,C0,9C,C0,A8,C0,A4' # TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 / TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 = ECDHE-RSA-AES128-GCM-SHA256 / ECDHE-RSA-AES256-GCM-SHA384 # came in Server 2016, see https://notsomany.com/2016/08/26/achieve-a-on-sslabs-iis-8-5-windows-2012-r2/ # https://docs.microsoft.com/en-us/windows/win32/secauthn/cipher-suites-in-schannel - local more_excluded_ciphers='C0,2f, C0,30' + local more_excluded_ciphers='C0,2F, C0,30' + # These are the three NIST curves allowed only. Keep in mind prime256v1=secp256r1 and MS labels them as P256, P384 and P521 + local allowed_curves="prime256v1 secp384r1 secp521r1" + local curve="" tls_ext="" local -i sclient_success=0 - local is_iis8=true local server_banner="" + local check_patches=" - check patches locally to confirm" local cve="CVE-2014-6321" local cwe="CWE-94" local jsonID="winshock" @@ -17475,49 +17494,36 @@ run_winshock() { if [[ "$(has_server_protocol "tls1_3")" -eq 0 ]] ; then # There's no MS server supporting TLS 1.3. Winshock was way back in time pr_svrty_best "not vulnerable (OK)" - debugme echo " - TLS 1.3 found" + debugme1 echo " - TLS 1.3 found" fileout "$jsonID" "OK" "not vulnerable " "$cve" "$cwe" outln return 0 fi - # Next we weed out is whether we run HTTP or RDP (on standard port) - if [[ $SERVICE != HTTP ]] && [[ $PORT != 3389 ]]; then - prln_svrty_best "not vulnerable (OK) - no HTTP or RDP" - fileout "$jsonID" "OK" "not vulnerable - no HTTP or RDP" "$cve" "$cwe" - return 0 - fi - # Now we check whether any CAMELLIA, ARIA, CCM or CHACHA cipher is available. # We do this in two shots in order to stay below the 128 cipher limit tls_sockets "03" "${aria_ciphers},${chacha_ccm_ciphers}, 00,ff" sclient_success=$? if [[ $sclient_success -eq 0 ]] || [[ "$sclient_success" -eq 2 ]]; then - pr_svrty_best "not vulnerable (OK)" - debugme echo " - ARIA, CHACHA or CCM ciphers found" + pr_svrty_best "not vulnerable (OK)" ; outln " - ARIA, CHACHA or CCM ciphers found" fileout "$jsonID" "OK" "not vulnerable " "$cve" "$cwe" - outln return 0 fi tls_sockets "03" "${camellia_ciphers},${more_excluded_ciphers}, 00,ff" sclient_success=$? if [[ $sclient_success -eq 0 ]] || [[ "$sclient_success" -eq 2 ]]; then - pr_svrty_best "not vulnerable (OK)" - debugme echo " - CAMELLIA or ECDHE_RSA GCM ciphers found" + pr_svrty_best "not vulnerable (OK)"; outln " - CAMELLIA or ECDHE_RSA GCM ciphers found" fileout "$jsonID" "OK" "not vulnerable " "$cve" "$cwe" - outln return 0 fi - # Now we have RDP and HTTP left and need to check the fixed ciphers - tls_sockets "03" "${ws_ciphers_hex}, 00,ff" + # Now we need to check the fixed ciphers + tls_sockets "03" "${wsfixed_ciphers}, 00,ff" sclient_success=$? if [[ $sclient_success -eq 0 ]] || [[ "$sclient_success" -eq 2 ]]; then # has rollup ciphers - pr_svrty_best "not vulnerable (OK)" - debugme echo " - GCM rollup ciphers found" + pr_svrty_best "not vulnerable (OK)"; outln " - GCM rollup ciphers found" fileout "$jsonID" "OK" "not vulnerable" "$cve" "$cwe" - outln return 0 elif [[ $sclient_success -ne 1 ]]; then prln_warning "check failed, connect problem" @@ -17525,12 +17531,71 @@ run_winshock() { return 1 fi + # Basic idea: https://en.wikipedia.org/wiki/Comparison_of_TLS_implementations#Supported_elliptic_curves + # [[ -z "$CURVES_OFFERED" ]] && sub_check_curves + if [[ -n "$CURVES_OFFERED" ]]; then + # Check whether there are any additional curves besides $allowed_curves + for curve in $CURVES_OFFERED; do + if ! [[ $allowed_curves =~ $curve ]]; then + pr_svrty_best "not vulnerable (OK)"; outln " - curve $curve detected" + fileout "$jsonID" "OK" "not vulnerable - curve $curve detected" "$cve" "$cwe" + return 0 + fi + done + fi + #FIXME: The catch is that when a user didn't invoke run_fs() before, this wasn't processed + CURVES_OFFERED + # is empty. So we could call it like above but need to move curves detection into a seperate function + # (~ sub_check_curves) which is some work. But also for the sake of clean code this needs to be done. + + + [[ -z "$TLS_EXTENSIONS" ]] && determine_tls_extensions + # Basis of the following https://en.wikipedia.org/wiki/Comparison_of_TLS_implementations#Extensions + # Our standard: https://www.iana.org/assignments/tls-extensiontype-values/tls-extensiontype-values.xhtml + + # According to Wikipedia above these are the ones which can be detected unders version of Windows + # Secure Renegotiation, Server Name Indication, Certificate Status Request, Supplemental Data, Extended Master Secret, ALPN + # supplemental_data(23) (RFC 4680) seems to have been overwritten by extended master secret(23) RFC 7627 + # local -a allowed_tls_ext=("server name" "status_request" "extended master secret" "application layer protocol negotiation") + # Instead we rather focus on the ones which according to that source weren't available + # Encrypt-then-MAC, Maximum Fragment Length, Keying Material Exporter, TLS Fallback SCSV, ClientHello Padding + # Padding is client side. Don't know what they mean by the fallback SCSV. That is not an extension + local -a forbidden_tls_ext=("encrypt-then-mac" "max fragment length") + # Open whether ec_point_formats, supported_groups(=elliptic_curves), heartbeat are supported under windows <=2012 + # key_share and supported_versions are extensions which came with TLS 1.3. We checked the protocol before. + if [[ -n "$TLS_EXTENSIONS" ]]; then + # Check whether there are any TLS extension which should not be available under <= Windows 2012 R2 + for tls_ext in $TLS_EXTENSIONS; do + # We use the whole array, got to be careful when the array becomes bigger (unintented match) + if [[ ${forbidden_tls_ext[@]} =~ $tls_ext ]]; then + pr_svrty_best "not vulnerable (OK)"; outln " - TLS extension $tls_ext detected" + fileout "$jsonID" "OK" "not vulnerable - TLS extension $tls_ext detected" "$cve" "$cwe" + return 0 + fi + done + fi + + # More would be possible if we look @ the following: + # See also https://github.com/cisco/joy/blob/master/fingerprinting/resources/fingerprint_db.json.gz + # https://resources.sei.cmu.edu/asset_files/Presentation/2019_017_001_539902.pdf + # https://raw.githubusercontent.com/cisco/joy/master/doc/using-joy-fingerprinting-00.pdf + + + + # Now the solid determination more or less done. What's left now is to detect the service + # and perform an educated guess. + + # Next we weed out is whether we run HTTP or RDP (on standard port). + # Using the experimental flag we can test it also on other ports / services + if [[ $SERVICE != HTTP ]] && [[ $PORT != 3389 ]] && ! "$EXPERIMENTAL"; then + pr_svrty_best "not vulnerable (OK)"; outln " - no HTTP or RDP" + fileout "$jsonID" "OK" "not vulnerable - no HTTP or RDP" "$cve" "$cwe" + return 0 + fi + if [[ $SERVICE != HTTP ]] && [[ $PORT == 3389 ]]; then - # We take a guess here for RDP as we don't have a banner - out "probably " - pr_svrty_critical "vulnerable (NOT ok)" - outln " - check patches locally to confirm" - fileout "${jsonID}" "CRITICAL" "probably vulnerable (NOT OK). Check patches locally to confirm" + # We take a security guess here (better safe than sorry) for RDP as we don't have a banner + out "probably "; pr_svrty_critical "vulnerable (NOT ok)"; outln "$check_patches" + fileout "${jsonID}" "CRITICAL" "probably vulnerable (NOT OK) $check_patches" return 0 fi @@ -17550,15 +17615,27 @@ run_winshock() { fi if [[ $server_banner =~ Microsoft-IIS\/8.5 ]]; then # Windows 2012 R2 is less likely than Windows 2012 - out "probably " - pr_svrty_critical "vulnerable (NOT ok)" - outln " - check patches locally to confirm" - fileout "${jsonID}" "CRITICAL" "probably vulnerable (NOT OK). Check patches locally to confirm" + out "probably "; pr_svrty_critical "vulnerable (NOT ok)"; outln "$check_patches" + fileout "${jsonID}" "CRITICAL" "probably vulnerable (NOT OK) $check_patches" elif [[ $server_banner =~ Microsoft-IIS\/8.0 ]]; then - out "likely " - pr_svrty_critical "VULNERABLE (NOT ok)" - outln " - check patches locally to confirm" - fileout "${jsonID}" "CRITICAL" "likely vulnerable (NOT OK). Check patches locally to confirm" + out "likely "; pr_svrty_critical "VULNERABLE (NOT ok)"; outln "$check_patches" + fileout "${jsonID}" "CRITICAL" "likely vulnerable (NOT OK) $check_patches" + elif [[ $server_banner =~ Microsoft-HTTPAPI\/2.0 ]]; then + # This is http.sys. It may or may not indicate a 2012 server. IIS is not yet configured though. + # So we have a peek on port 80 + http_get $NODE "$TEMPDIR/$NODE.$NODEIP.http-header.txt" + server_banner="$(grep -Eai '^Server:' $TEMPDIR/$NODE.$NODEIP.http-header.txt)" + if [[ $server_banner =~ Microsoft-IIS\/8.5 ]]; then + out "probably "; pr_svrty_critical "vulnerable (NOT ok)"; outln "$check_patches" + fileout "${jsonID}" "CRITICAL" "probably vulnerable (NOT OK) $check_patches" + elif [[ $server_banner =~ Microsoft-IIS\/8.0 ]]; then + out "likely "; pr_svrty_critical "VULNERABLE (NOT ok)"; outln "$check_patches" + fileout "${jsonID}" "CRITICAL" "likely vulnerable (NOT OK) $check_patches" + else + out "likely "; prln_svrty_best "not vulnerable (OK)" + fileout "$jsonID" "OK" "not vulnerable" "$cve" "$cwe" + outln + fi else pr_svrty_best "not vulnerable (OK)" outln " - doesn't seem to be IIS 8.x"