testssl(1) Command line tool to check TLS/SSL ciphers, protocols and cryptographic flaws


testssl is a free command line tool which checks a server's service on any port for the support of TLS/SSL ciphers, protocols as well as recent cryptographic flaws and more.

Key features:

* Clear output: you can tell easily whether anything is good or bad

* Ease of installation: It works for Linux, Darwin, FreeBSD and MSYS2/Cygwin out of the box: no need to install or configure something, no gems, CPAN, pip or the like.

* Flexibility: You can test any SSL/TLS enabled and STARTTLS service, not only webservers at port 443

* Toolbox: Several command line options help you to run YOUR test and configure YOUR output

* Reliability: features are tested thoroughly

* Verbosity: If a particular check cannot be performed because of a missing capability on your client side, you'll get a warning

* Privacy: It's only you who sees the result, not a third party

* Freedom: It's 100% open source. You can look at the code, see what's going on and you can change it. Heck, even the development is open (github)

-h, --help
what you're looking at
-b, --banner
displays banner + version of testssl
-v, --version
same as previous
-V, --local
pretty print all local ciphers
-V, --local <pattern>
which local ciphers with <pattern> are available? (if pattern not a number: word match)

testssl <options> URI ("testssl URI" does everything except -E)

-e, --each-cipher
checks each local cipher remotely
-E, --cipher-per-proto
checks those per protocol
-f, --ciphers
checks common cipher suites
-p, --protocols
checks TLS/SSL protocols
-S, --server_defaults
displays the servers default picks and certificate info
-P, --preference
displays the servers picks: protocol+cipher
-y, --spdy, --npn
checks for SPDY/NPN
-x, --single-cipher <pattern> tests matched <pattern> of ciphers
(if <pattern> not a number: word match)
-U, --vulnerable
tests all vulnerabilities
-B, --heartbleed
tests for heartbleed vulnerability
-I, --ccs, --ccs-injection
tests for CCS injection vulnerability
-R, --renegotiation
tests for renegotiation vulnerabilities
-C, --compression, --crime
tests for CRIME vulnerability
-T, --breach
tests for BREACH vulnerability
-O, --poodle
tests for POODLE (SSL) vulnerability
-Z, --tls-fallback
checks TLS_FALLBACK_SCSV mitigation
-F, --freak
tests for FREAK vulnerability
-A, --beast
tests for BEAST vulnerability
-J, --logjam
tests for LOGJAM vulnerability
-s, --pfs, --fs,--nsa
checks (perfect) forward secrecy settings
-4, --rc4, --appelbaum
which RC4 ciphers are being offered?
-H, --header, --headers
tests HSTS, HPKP, server/app banner, security headers, cookie, reverse proxy, IPv4 address
special invocations:
-t, --starttls <protocol>
does a default run against a STARTTLS enabled <protocol>
--xmpphost <to_domain>
for STARTTLS enabled XMPP it supplies the XML stream to-'' domain -- sometimes needed
--mx <domain/host>
tests MX records from high to low priority (STARTTLS, port 25)
--ip <ipv4>
a) tests the supplied <ipv4> instead of resolving host(s) in URI b) arg "one" means: just test the first DNS returns (useful for multiple IPs)
--file <file name>
mass testing option: Just put multiple testssl command lines in <file name>, one line per instance. Comments via # allowed, EOF signals end of <file name>.

partly mandatory parameters:

host|host:port|URL|URL:port (port 443 is assumed unless otherwise specified)
an ignore case word pattern of cipher hexcode or any other string in the name, kx or bits
is one of ftp,smtp,pop3,imap,xmpp,telnet,ldap (for the latter two you need e.g. the supplied openssl)

tuning options:

if protocol check fails it assumes HTTP protocol and enforces HTTP checks
fallback to checks with OpenSSL where sockets are normally used
--openssl <PATH>
use this openssl binary (default: look in $PATH, $RUN_DIR of testssl
--proxy <host>:<port>
connect via the specified HTTP proxy
be less verbose wrt referer headers
don't output the banner. By doing this you acknowledge usage terms normally appearing in the banner
wide output for tests like RC4, BEAST. PFS also with hexcode, kx, strength, RFC name
for wide outputs: display all ciphers tested -- not only succeeded ones
--warnings <batch|off|false>
"batch" doesn't wait for keypress, "off" or "false" skips connection warning
--color <0|1|2>
0: no escape or other codes, 1: b/w escape codes, 2: color (default)
--debug <0-6>
1: screen output normal but debug output in temp files. 2-6: see line ~105

All options requiring a value can also be called with '=' (e.g. testssl -t=,smtp/ --wide --openssl=/usr/bin/openssl <URI>. <URI> is always the last parameter.

Need HTML output? Just pipe through "aha" (Ansi HTML Adapter: github.com/theZiz/aha) like

"testssl <options> <URI> | aha >output.html"


This manual page was written by ChangZhuo Chen <[email protected]> for the Debian GNU/Linux system (but may be used by others).