What ciphers are used by your smtp server? Well that’s a question I got asked today.
Take a look at this testssl.sh - it spawned a whole report about my SMTP server that included ciphers and a whole lot more:
https://github.com/drwetter/testssl.sh
bash ./testssl.sh -t smtp smtp.server.com:587
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testssl.sh 3.1dev from https://testssl.sh/dev/
(19f2c28 2020-07-15 11:51:34 -- )
This program is free software. Distribution and
modification under GPLv2 permitted.
USAGE w/o ANY WARRANTY. USE IT AT YOUR OWN RISK!
Please file bugs @ https://testssl.sh/bugs/
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Using "OpenSSL 1.0.2-chacha (1.0.2k-dev)" [~183 ciphers]
on detective:./bin/openssl.Linux.x86_64
(built: "Jan 18 17:12:17 2019", platform: "linux-x86_64")
Start 2020-07-16 16:19:43 -->> 136.143.182.56:587 (smtp.server.com) <<--
rDNS (136.143.182.56): --
Service set: STARTTLS via SMTP
Testing protocols via sockets
SSLv2 not offered (OK)
SSLv3 not offered (OK)
TLS 1 offered (deprecated)
TLS 1.1 offered (deprecated)
TLS 1.2 offered (OK)
TLS 1.3 not offered and downgraded to a weaker protocol
Testing cipher categories
NULL ciphers (no encryption) not offered (OK)
Anonymous NULL Ciphers (no authentication) not offered (OK)
Export ciphers (w/o ADH+NULL) not offered (OK)
LOW: 64 Bit + DES, RC[2,4], MD5 (w/o export) offered (NOT ok)
Triple DES Ciphers / IDEA not offered
Obsoleted CBC ciphers (AES, ARIA etc.) offered
Strong encryption (AEAD ciphers) with no FS offered (OK)
Forward Secrecy strong encryption (AEAD ciphers) offered (OK)
Testing server's cipher preferences
Has server cipher order? no (NOT ok)
Negotiated protocol TLSv1.2
Negotiated cipher AES128-GCM-SHA256 -- inconclusive test, matching cipher in list missing, better see below
Cipher per protocol
Hexcode Cipher Suite Name (OpenSSL) KeyExch. Encryption Bits Cipher Suite Name (IANA/RFC)
-----------------------------------------------------------------------------------------------------------------------------
SSLv2
-
SSLv3
-
TLSv1 (no server order, thus listed by strength)
xc014 ECDHE-RSA-AES256-SHA ECDH 521 AES 256 TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA
x35 AES256-SHA RSA AES 256 TLS_RSA_WITH_AES_256_CBC_SHA
xc013 ECDHE-RSA-AES128-SHA ECDH 521 AES 128 TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
x2f AES128-SHA RSA AES 128 TLS_RSA_WITH_AES_128_CBC_SHA
x05 RC4-SHA RSA RC4 128 TLS_RSA_WITH_RC4_128_SHA
TLSv1.1 (no server order, thus listed by strength)
xc014 ECDHE-RSA-AES256-SHA ECDH 521 AES 256 TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA
x35 AES256-SHA RSA AES 256 TLS_RSA_WITH_AES_256_CBC_SHA
xc013 ECDHE-RSA-AES128-SHA ECDH 521 AES 128 TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
x2f AES128-SHA RSA AES 128 TLS_RSA_WITH_AES_128_CBC_SHA
x05 RC4-SHA RSA RC4 128 TLS_RSA_WITH_RC4_128_SHA
TLSv1.2 (no server order, thus listed by strength)
xc030 ECDHE-RSA-AES256-GCM-SHA384 ECDH 521 AESGCM 256 TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
xc014 ECDHE-RSA-AES256-SHA ECDH 521 AES 256 TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA
x9d AES256-GCM-SHA384 RSA AESGCM 256 TLS_RSA_WITH_AES_256_GCM_SHA384
x35 AES256-SHA RSA AES 256 TLS_RSA_WITH_AES_256_CBC_SHA
xc02f ECDHE-RSA-AES128-GCM-SHA256 ECDH 521 AESGCM 128 TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
xc027 ECDHE-RSA-AES128-SHA256 ECDH 521 AES 128 TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256
xc013 ECDHE-RSA-AES128-SHA ECDH 521 AES 128 TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
x9c AES128-GCM-SHA256 RSA AESGCM 128 TLS_RSA_WITH_AES_128_GCM_SHA256
x3c AES128-SHA256 RSA AES 128 TLS_RSA_WITH_AES_128_CBC_SHA256
x2f AES128-SHA RSA AES 128 TLS_RSA_WITH_AES_128_CBC_SHA
x05 RC4-SHA RSA RC4 128 TLS_RSA_WITH_RC4_128_SHA
TLSv1.3
-
Testing robust forward secrecy (FS) -- omitting Null Authentication/Encryption, 3DES, RC4
FS is offered (OK) ECDHE-RSA-AES256-GCM-SHA384 ECDHE-RSA-AES256-SHA ECDHE-RSA-AES128-GCM-SHA256 ECDHE-RSA-AES128-SHA256
ECDHE-RSA-AES128-SHA
Elliptic curves offered: prime256v1 secp384r1 secp521r1
Testing server defaults (Server Hello)
TLS extensions (standard) "renegotiation info/#65281" "extended master secret/#23"
Session Ticket RFC 5077 hint no -- no lifetime advertised
SSL Session ID support yes
Session Resumption Tickets no, ID: no
TLS clock skew -1 sec from localtime
Signature Algorithm SHA256 with RSA
Server key size RSA 2048 bits (exponent is 65537)
Server key usage Digital Signature, Key Encipherment
Server extended key usage TLS Web Server Authentication, TLS Web Client Authentication
Serial / Fingerprints 025A65A6DF2A63F2D67DE9E5363A1058 / SHA1 6A870FB27C3AE522AF1C8FDB02D022C65E24E0E9
SHA256 569557FA02E5E88E2C0193B7094FD11641497F6F3871799BFD92869286E45831
Common Name (CN) *.server.com
subjectAltName (SAN) *.server.com server.com
Issuer Thawte RSA CA 2018 (DigiCert Inc from US)
Trust (hostname) Ok via SAN wildcard and CN wildcard (same w/o SNI)
Chain of trust Ok
EV cert (experimental) no
Bad OCSP intermediate (exp.) Ok
ETS/"eTLS", visibility info not present
Certificate Validity (UTC) 248 >= 60 days (2019-03-23 00:00 --> 2021-03-22 12:00)
# of certificates provided 3
Certificate Revocation List http://cdp.thawte.com/ThawteRSACA2018.crl
OCSP URI http://status.thawte.com
OCSP stapling not offered
OCSP must staple extension --
DNS CAA RR (experimental) not offered
Certificate Transparency yes (certificate extension)
Testing vulnerabilities
Heartbleed (CVE-2014-0160) not vulnerable (OK), no heartbeat extension
CCS (CVE-2014-0224) not vulnerable (OK)
ROBOT not vulnerable (OK)
Secure Renegotiation (RFC 5746) supported (OK)
Secure Client-Initiated Renegotiation VULNERABLE (NOT ok), potential DoS threat
CRIME, TLS (CVE-2012-4929) not vulnerable (OK) (not using HTTP anyway)
POODLE, SSL (CVE-2014-3566) not vulnerable (OK), no SSLv3 support
TLS_FALLBACK_SCSV (RFC 7507) Rerun including POODLE SSL check. Downgrade attack prevention NOT supported
SWEET32 (CVE-2016-2183, CVE-2016-6329) not vulnerable (OK)
FREAK (CVE-2015-0204) not vulnerable (OK)
DROWN (CVE-2016-0800, CVE-2016-0703) not vulnerable on this host and port (OK)
make sure you don't use this certificate elsewhere with SSLv2 enabled services
https://censys.io/ipv4?q=569557FA02E5E88E2C0193B7094FD11641497F6F3871799BFD92869286E45831 could help you to find out
LOGJAM (CVE-2015-4000), experimental not vulnerable (OK): no DH EXPORT ciphers, no DH key detected with <= TLS 1.2
BEAST (CVE-2011-3389) TLS1: ECDHE-RSA-AES256-SHA AES256-SHA ECDHE-RSA-AES128-SHA AES128-SHA
VULNERABLE -- but also supports higher protocols TLSv1.1 TLSv1.2 (likely mitigated)
LUCKY13 (CVE-2013-0169), experimental potentially VULNERABLE, uses cipher block chaining (CBC) ciphers with TLS. Check patches
RC4 (CVE-2013-2566, CVE-2015-2808) VULNERABLE (NOT ok): RC4-SHA
Running client simulations via sockets
Android 8.1 (native) TLSv1.2 ECDHE-RSA-AES128-GCM-SHA256, 256 bit ECDH (P-256)
Android 9.0 (native) TLSv1.2 ECDHE-RSA-AES128-GCM-SHA256, 256 bit ECDH (P-256)
Android 10.0 (native) TLSv1.2 ECDHE-RSA-AES128-GCM-SHA256, 256 bit ECDH (P-256)
Java 6u45 TLSv1.0 AES128-SHA, No FS
Java 7u25 TLSv1.0 ECDHE-RSA-AES128-SHA, 256 bit ECDH (P-256)
Java 8u161 TLSv1.2 ECDHE-RSA-AES256-SHA, 256 bit ECDH (P-256)
Java 11.0.2 (OpenJDK) TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384, 256 bit ECDH (P-256)
Java 12.0.1 (OpenJDK) TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384, 256 bit ECDH (P-256)
OpenSSL 1.0.2e TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384, 256 bit ECDH (P-256)
OpenSSL 1.1.0l (Debian) TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384, 256 bit ECDH (P-256)
OpenSSL 1.1.1d (Debian) TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384, 256 bit ECDH (P-256)
Thunderbird (68.3) TLSv1.2 ECDHE-RSA-AES128-GCM-SHA256, 256 bit ECDH (P-256)
Rating (experimental)
Rating specs (not complete) SSL Labs's 'SSL Server Rating Guide' (version 2009q from 2020-01-30)
Specification documentation https://github.com/ssllabs/research/wiki/SSL-Server-Rating-Guide
Protocol Support (weighted) 0 (0)
Key Exchange (weighted) 0 (0)
Cipher Strength (weighted) 0 (0)
Final Score 0
Overall Grade T
Grade cap reasons Grade capped to T. Encryption via STARTTLS is not mandatory (opportunistic).
Grade capped to B. TLS 1.1 offered
Grade capped to B. TLS 1.0 offered
Grade capped to B. RC4 ciphers offered
Grade capped to A. Does not support TLS_FALLBACK_SCSV
Done 2020-07-16 16:24:05 [ 266s] -->> 136.143.182.56:587 (smtp.server.com) <<--Not output from one of our servers - just a random smtp server.