(mozilla-projects-nss-reference-nss-tools-ssltab)=

# NSS tools : ssltab

:::{container}
Name

ssltap — Tap into SSL connections and display the data going by

Synopsis

libssltap [-vhfsxl] [-p port] [hostname:port]

Description

The SSL Debugging Tool ssltap is an SSL-aware command-line proxy. It

watches TCP connections and displays the data going by. If a connection is

SSL, the data display includes interpreted SSL records and handshaking

Options

-v

Print a version string for the tool.

-h

Turn on hex/ASCII printing. Instead of outputting raw data, the

command interprets each record as a numbered line of hex values,

followed by the same data as ASCII characters. The two parts are

separated by a vertical bar. Nonprinting characters are replaced

by dots.

-f

Turn on fancy printing. Output is printed in colored HTML. Data

sent from the client to the server is in blue; the server's reply

is in red. When used with looping mode, the different connections

are separated with horizontal lines. You can use this option to

upload the output into a browser.

-s

Turn on SSL parsing and decoding. The tool does not automatically

detect SSL sessions. If you are intercepting an SSL connection,

use this option so that the tool can detect and decode SSL

structures.

If the tool detects a certificate chain, it saves the DER-encoded

certificates into files in the current directory. The files are

named cert.0x, where x is the sequence number of the certificate.

If the -s option is used with -h, two separate parts are printed

for each record: the plain hex/ASCII output, and the parsed SSL

output.

-x

Turn on hex/ASCII printing of undecoded data inside parsed SSL

records. Used only with the -s option. This option uses the same

output format as the -h option.

-l prefix

Turn on looping; that is, continue to accept connections rather

than stopping after the first connection is complete.

-p port

Change the default rendezvous port (1924) to another port.

The following are well-known port numbers:

\* HTTP 80

\* HTTPS 443

\* SMTP 25

\* FTP 21

\* IMAP 143

\* IMAPS 993 (IMAP over SSL)

\* NNTP 119

\* NNTPS 563 (NNTP over SSL)

Usage and Examples

You can use the SSL Debugging Tool to intercept any connection

information. Although you can run the tool at its most basic by issuing

the ssltap command with no options other than hostname:port, the

information you get in this way is not very useful. For example, assume

your development machine is called intercept. The simplest way to use the

debugging tool is to execute the following command from a command shell:

\$ ssltap <www.netscape.com>

The program waits for an incoming connection on the default port 1924. In

your browser window, enter the URL

<http://intercept:1924>

. The browser

retrieves the requested page from the server at <www.netscape.com>, but the

page is intercepted and passed on to the browser by the debugging tool on

intercept. On its way to the browser, the data is printed to the command

shell from which you issued the command. Data sent from the client to the

server is surrounded by the following symbols: --> [ data ] Data sent from

the server to the client is surrounded by the following symbols: "left

arrow"-- [ data ] The raw data stream is sent to standard output and is

not interpreted in any way. This can result in peculiar effects, such as

sounds, flashes, and even crashes of the command shell window. To output a

basic, printable interpretation of the data, use the -h option, or, if you

are looking at an SSL connection, the -s option. You will notice that the

page you retrieved looks incomplete in the browser. This is because, by

default, the tool closes down after the first connection is complete, so

the browser is not able to load images. To make the tool continue to

accept connections, switch on looping mode with the -l option. The

following examples show the output from commonly used combinations of

options.

Example 1

\$ ssltap.exe -sx -p 444 interzone.mcom.com:443 > sx.txt

Output

Connected to interzone.mcom.com:443

-->; \[

alloclen = 66 bytes

[ssl2] ClientHelloV2 {

version = {0x03, 0x00}

cipher-specs-length = 39 (0x27)

sid-length = 0 (0x00)

challenge-length = 16 (0x10)

cipher-suites = {

(0x010080) SSL2/RSA/RC4-128/MD5

(0x020080) SSL2/RSA/RC4-40/MD5

(0x030080) SSL2/RSA/RC2CBC128/MD5

(0x040080) SSL2/RSA/RC2CBC40/MD5

(0x060040) SSL2/RSA/DES64CBC/MD5

(0x0700c0) SSL2/RSA/3DES192EDE-CBC/MD5

(0x000004) SSL3/RSA/RC4-128/MD5

(0x00ffe0) SSL3/RSA-FIPS/3DES192EDE-CBC/SHA

(0x00000a) SSL3/RSA/3DES192EDE-CBC/SHA

(0x00ffe1) SSL3/RSA-FIPS/DES64CBC/SHA

(0x000009) SSL3/RSA/DES64CBC/SHA

(0x000003) SSL3/RSA/RC4-40/MD5

(0x000006) SSL3/RSA/RC2CBC40/MD5

}

session-id = { }

challenge = { 0xec5d 0x8edb 0x37c9 0xb5c9 0x7b70 0x8fe9 0xd1d3

0x2592 }

}

\]

\<-- \[

SSLRecord {

0: 16 03 00 03 e5 |.....

type = 22 (handshake)

version = { 3,0 }

length = 997 (0x3e5)

handshake {

0: 02 00 00 46 |...F

type = 2 (server_hello)

length = 70 (0x000046)

ServerHello {

server_version = {3, 0}

random = {...}

0: 77 8c 6e 26 6c 0c ec c0 d9 58 4f 47 d3 2d 01 45 |

wn&l.ì..XOG.-.E

10: 5c 17 75 43 a7 4c 88 c7 88 64 3c 50 41 48 4f 7f |

\\.uC§L.Ç.d\<PAHO.

session ID = {

length = 32

contents = {..}

0: 14 11 07 a8 2a 31 91 29 11 94 40 37 57 10 a7 32 | ...¨\*1.)..@7W.§2

10: 56 6f 52 62 fe 3d b3 65 b1 e4 13 0f 52 a3 c8 f6 | VoRbþ=³e±...R£È.

}

cipher_suite = (0x0003) SSL3/RSA/RC4-40/MD5

}

0: 0b 00 02 c5 |...Å

type = 11 (certificate)

length = 709 (0x0002c5)

CertificateChain {

chainlength = 706 (0x02c2)

Certificate {

size = 703 (0x02bf)

data = { saved in file 'cert.001' }

}

}

0: 0c 00 00 ca |....

type = 12 (server_key_exchange)

length = 202 (0x0000ca)

0: 0e 00 00 00 |....

type = 14 (server_hello_done)

length = 0 (0x000000)

}

}

\]

--> \[

SSLRecord {

0: 16 03 00 00 44 |....D

type = 22 (handshake)

version = { 3,0 }

length = 68 (0x44)

handshake {

0: 10 00 00 40 |...@

type = 16 (client_key_exchange)

length = 64 (0x000040)

ClientKeyExchange {

message = {...}

}

}

}

\]

--> \[

SSLRecord {

0: 14 03 00 00 01 |.....

type = 20 (change_cipher_spec)

version = { 3,0 }

length = 1 (0x1)

0: 01 |.

}

SSLRecord {

0: 16 03 00 00 38 |....8

type = 22 (handshake)

version = { 3,0 }

length = 56 (0x38)

< encrypted >

}

\]

\<-- \[

SSLRecord {

0: 14 03 00 00 01 |.....

type = 20 (change_cipher_spec)

version = { 3,0 }

length = 1 (0x1)

0: 01 |.

}

\]

\<-- \[

SSLRecord {

0: 16 03 00 00 38 |....8

type = 22 (handshake)

version = { 3,0 }

length = 56 (0x38)

< encrypted >

}

\]

--> \[

SSLRecord {

0: 17 03 00 01 1f |.....

type = 23 (application_data)

version = { 3,0 }

length = 287 (0x11f)

< encrypted >

}

\]

\<-- \[

SSLRecord {

0: 17 03 00 00 a0 |....

type = 23 (application_data)

version = { 3,0 }

length = 160 (0xa0)

< encrypted >

}

\]

\<-- \[

SSLRecord {

0: 17 03 00 00 df |....ß

type = 23 (application_data)

version = { 3,0 }

length = 223 (0xdf)

< encrypted >

}

SSLRecord {

0: 15 03 00 00 12 |.....

type = 21 (alert)

version = { 3,0 }

length = 18 (0x12)

< encrypted >

}

\]

Server socket closed.

Example 2

The -s option turns on SSL parsing. Because the -x option is not used in

this example, undecoded values are output as raw data. The output is

routed to a text file.

\$ ssltap -s -p 444 interzone.mcom.com:443 > s.txt

Output

Connected to interzone.mcom.com:443

--> \[

alloclen = 63 bytes

[ssl2] ClientHelloV2 {

version = {0x03, 0x00}

cipher-specs-length = 36 (0x24)

sid-length = 0 (0x00)

challenge-length = 16 (0x10)

cipher-suites = {

(0x010080) SSL2/RSA/RC4-128/MD5

(0x020080) SSL2/RSA/RC4-40/MD5

(0x030080) SSL2/RSA/RC2CBC128/MD5

(0x060040) SSL2/RSA/DES64CBC/MD5

(0x0700c0) SSL2/RSA/3DES192EDE-CBC/MD5

(0x000004) SSL3/RSA/RC4-128/MD5

(0x00ffe0) SSL3/RSA-FIPS/3DES192EDE-CBC/SHA

(0x00000a) SSL3/RSA/3DES192EDE-CBC/SHA

(0x00ffe1) SSL3/RSA-FIPS/DES64CBC/SHA

(0x000009) SSL3/RSA/DES64CBC/SHA

(0x000003) SSL3/RSA/RC4-40/MD5

}

session-id = { }

challenge = { 0x713c 0x9338 0x30e1 0xf8d6 0xb934 0x7351 0x200c

0x3fd0 }

\]

>-- \[

SSLRecord {

type = 22 (handshake)

version = { 3,0 }

length = 997 (0x3e5)

handshake {

type = 2 (server_hello)

length = 70 (0x000046)

ServerHello {

server_version = {3, 0}

random = {...}

session ID = {

length = 32

contents = {..}

}

cipher_suite = (0x0003) SSL3/RSA/RC4-40/MD5

}

type = 11 (certificate)

length = 709 (0x0002c5)

CertificateChain {

chainlength = 706 (0x02c2)

Certificate {

size = 703 (0x02bf)

data = { saved in file 'cert.001' }

}

}

type = 12 (server_key_exchange)

length = 202 (0x0000ca)

type = 14 (server_hello_done)

length = 0 (0x000000)

}

}

\]

--> \[

SSLRecord {

type = 22 (handshake)

version = { 3,0 }

length = 68 (0x44)

handshake {

type = 16 (client_key_exchange)

length = 64 (0x000040)

ClientKeyExchange {

message = {...}

}

}

}

\]

--> \[

SSLRecord {

type = 20 (change_cipher_spec)

version = { 3,0 }

length = 1 (0x1)

}

SSLRecord {

type = 22 (handshake)

version = { 3,0 }

length = 56 (0x38)

> encrypted >

}

\]

>-- \[

SSLRecord {

type = 20 (change_cipher_spec)

version = { 3,0 }

length = 1 (0x1)

}

\]

>-- \[

SSLRecord {

type = 22 (handshake)

version = { 3,0 }

length = 56 (0x38)

> encrypted >

}

\]

--> \[

SSLRecord {

type = 23 (application_data)

version = { 3,0 }

length = 287 (0x11f)

> encrypted >

}

\]

\[

SSLRecord {

type = 23 (application_data)

version = { 3,0 }

length = 160 (0xa0)

> encrypted >

}

\]

>-- \[

SSLRecord {

type = 23 (application_data)

version = { 3,0 }

length = 223 (0xdf)

> encrypted >

}

SSLRecord {

type = 21 (alert)

version = { 3,0 }

length = 18 (0x12)

> encrypted >

}

\]

Server socket closed.

Example 3

In this example, the -h option turns hex/ASCII format. There is no SSL

parsing or decoding. The output is routed to a text file.

\$ ssltap -h -p 444 interzone.mcom.com:443 > h.txt

Output

Connected to interzone.mcom.com:443

--> \[

0: 80 40 01 03 00 00 27 00 00 00 10 01 00 80 02 00 | .@....'.........

10: 80 03 00 80 04 00 80 06 00 40 07 00 c0 00 00 04 | .........@......

20: 00 ff e0 00 00 0a 00 ff e1 00 00 09 00 00 03 00 | ........á.......

30: 00 06 9b fe 5b 56 96 49 1f 9f ca dd d5 ba b9 52 | ..þ\[V.I.xd9 ...º¹R

40: 6f 2d |o-

\]

\<-- \[

0: 16 03 00 03 e5 02 00 00 46 03 00 7f e5 0d 1b 1d | ........F.......

10: 68 7f 3a 79 60 d5 17 3c 1d 9c 96 b3 88 d2 69 3b | h.:y\`..\<..³.Òi;

20: 78 e2 4b 8b a6 52 12 4b 46 e8 c2 20 14 11 89 05 | x.K.¦R.KFè. ...

30: 4d 52 91 fd 93 e0 51 48 91 90 08 96 c1 b6 76 77 | MR.ý..QH.....¶vw

40: 2a f4 00 08 a1 06 61 a2 64 1f 2e 9b 00 03 00 0b | \*ô..¡.a¢d......

50: 00 02 c5 00 02 c2 00 02 bf 30 82 02 bb 30 82 02 | ..Å......0...0..

60: 24 a0 03 02 01 02 02 02 01 36 30 0d 06 09 2a 86 | \$ .......60...\*.

70: 48 86 f7 0d 01 01 04 05 00 30 77 31 0b 30 09 06 | H.÷......0w1.0..

80: 03 55 04 06 13 02 55 53 31 2c 30 2a 06 03 55 04 | .U....US1,0\*..U.

90: 0a 13 23 4e 65 74 73 63 61 70 65 20 43 6f 6d 6d | ..#Netscape Comm

a0: 75 6e 69 63 61 74 69 6f 6e 73 20 43 6f 72 70 6f | unications Corpo

b0: 72 61 74 69 6f 6e 31 11 30 0f 06 03 55 04 0b 13 | ration1.0...U...

c0: 08 48 61 72 64 63 6f 72 65 31 27 30 25 06 03 55 | .Hardcore1'0%..U

d0: 04 03 13 1e 48 61 72 64 63 6f 72 65 20 43 65 72 | ....Hardcore Cer

e0: 74 69 66 69 63 61 74 65 20 53 65 72 76 65 72 20 | tificate Server

f0: 49 49 30 1e 17 0d 39 38 30 35 31 36 30 31 30 33 | II0...9805160103

\<additional data lines>

\]

\<additional records in same format>

Server socket closed.

Example 4

In this example, the -s option turns on SSL parsing, and the -h option

turns on hex/ASCII format. Both formats are shown for each record. The

output is routed to a text file.

\$ ssltap -hs -p 444 interzone.mcom.com:443 > hs.txt

Output

Connected to interzone.mcom.com:443

--> \[

0: 80 3d 01 03 00 00 24 00 00 00 10 01 00 80 02 00 | .=....\$.........

10: 80 03 00 80 04 00 80 06 00 40 07 00 c0 00 00 04 | .........@......

20: 00 ff e0 00 00 0a 00 ff e1 00 00 09 00 00 03 03 | ........á.......

30: 55 e6 e4 99 79 c7 d7 2c 86 78 96 5d b5 cf e9 |U..yÇxb0 ,.x.\]µÏé

alloclen = 63 bytes

[ssl2] ClientHelloV2 {

version = {0x03, 0x00}

cipher-specs-length = 36 (0x24)

sid-length = 0 (0x00)

challenge-length = 16 (0x10)

cipher-suites = {

(0x010080) SSL2/RSA/RC4-128/MD5

(0x020080) SSL2/RSA/RC4-40/MD5

(0x030080) SSL2/RSA/RC2CBC128/MD5

(0x040080) SSL2/RSA/RC2CBC40/MD5

(0x060040) SSL2/RSA/DES64CBC/MD5

(0x0700c0) SSL2/RSA/3DES192EDE-CBC/MD5

(0x000004) SSL3/RSA/RC4-128/MD5

(0x00ffe0) SSL3/RSA-FIPS/3DES192EDE-CBC/SHA

(0x00000a) SSL3/RSA/3DES192EDE-CBC/SHA

(0x00ffe1) SSL3/RSA-FIPS/DES64CBC/SHA

(0x000009) SSL3/RSA/DES64CBC/SHA

(0x000003) SSL3/RSA/RC4-40/MD5

}

session-id = { }

challenge = { 0x0355 0xe6e4 0x9979 0xc7d7 0x2c86 0x7896 0x5db

0xcfe9 }

}

\]

\<additional records in same formats>

Server socket closed.

Usage Tips

When SSL restarts a previous session, it makes use of cached information

to do a partial handshake. If you wish to capture a full SSL handshake,

restart the browser to clear the session id cache.

If you run the tool on a machine other than the SSL server to which you

are trying to connect, the browser will complain that the host name you

are trying to connect to is different from the certificate. If you are

using the default BadCert callback, you can still connect through a

dialog. If you are not using the default BadCert callback, the one you

supply must allow for this possibility.

See Also

The NSS Security Tools are also documented at

[1]

[http://www.mozilla.org/projects/security/pki/nss/](https://www.mozilla.org/projects/security/pki/nss/)

.

Additional Resources

NSS is maintained in conjunction with PKI and security-related projects

through Mozilla dn Fedora. The most closely-related project is Dogtag PKI,

with a project wiki at [2]

<http://pki.fedoraproject.org/wiki/>

.

For information specifically about NSS, the NSS project wiki is located at

[3]

[http://www.mozilla.org/projects/security/pki/nss/](https://www.mozilla.org/projects/security/pki/nss/)

.
The NSS site relates

directly to NSS code changes and releases.

Mailing lists: <mailto:pki-devel@redhat.com> and <mailto:pki-users@redhat.com>

IRC: Freenode at #dogtag-pki

Authors

The NSS tools were written and maintained by developers with Netscape and

now with Red Hat and Sun.

Authors: Elio Maldonado \<

<mailto:emaldona@redhat.com>

>, Deon Lackey

\<

<mailto:dlackey@redhat.com>

>.

Copyright

1. 2010, Red Hat, Inc. Licensed under the GNU Public License version 2.

References

Visible links

1.

[http://www.mozilla.org/projects/secu.../pki/nss/tools](https://www.mozilla.org/projects/security/pki/nss/tools)

1.

<http://pki.fedoraproject.org/wiki/>

1.

[http://www.mozilla.org/projects/security/pki/nss/](https://www.mozilla.org/projects/security/pki/nss/)
:::
