Empirical Analysis of Valid Values for VirtualHost ssl_ciphers for Testing TLS 1.2

[kurtkanaskie]

Problem Statement

Apigee is retiring TLS 1.0 and TLS 1.1 protocols on June 18th, 2018.

https://docs.apigee.com/release/notes/tls-retirement

Documentation for Virtual Host “ssl_ciphers” property does not provide a definitive list of valid values, it merely states valid openssl values can be used from the openssl man page.

https://docs.apigee.com/api-platform/fundamentals/virtual-host-property-reference

https://www.openssl.org/docs/man1.0.2/apps/ciphers.html

Use Case

As a Cloud Edge Orgadmin, I need to know the valid SSL cipher values to configure Virtual Hosts to use TLS 1.2 values so I can test my Apps before the TLS retirement on June 18th.

TL;DR

Based on empirical analysis, the valid individual values (one value in ssl_ciphers property) in a paid org deployed in Amazon us-east-1 and eu-west-1 using curl as the test client are:

AES128-GCM-SHA256
AES128-SHA256
AES256-GCM-SHA384
AES256-SHA256
DHE-RSA-AES128-GCM-SHA256
DHE-RSA-AES128-SHA256
DHE-RSA-AES256-GCM-SHA384
DHE-RSA-AES256-SHA256
ECDHE-RSA-AES128-GCM-SHA256
ECDHE-RSA-AES128-SHA256
ECDHE-RSA-AES256-GCM-SHA384
ECDHE-RSA-AES256-SHA384

NOTE: See very end of this document for Virtual Host management API call using these values.

Tests

• Tests via curl --tlsv1.0, --tlsv1.1 - failed
• Tests via curl --tlsv1 (used TLS 1.2) and --tlsv1.2 - worked

Observations

1. Some “valid” values were rejected by the management API as invalid.
2. Some “valid” values where accepted by the management API but curl commands for 1.2 failed.
3. Invalid values are accepted by the management API as long as one valid value was present (e.g. “foo:AES128-GCM-SHA256”).

Details

Test Setup

Org: paid org

Env: test

Deployment - Public Cloud - Amazon us-east-1 and eu-west-1

Procedure:

Configure Virtual Host with all possible values both as aggregate values and as single value.

Run curl with --tlsv1.0, --tlsv1.1 and tlsv1.2

Background

OpenSSL command strings

The following command can be used to get the list of ciphers suite names:

openssl ciphers -v -tls1 | grep TLSv1.2 | sort | cut -d ' ' -f1

AES128-GCM-SHA256
AES128-SHA256
AES256-GCM-SHA384
AES256-SHA256
<omitted for brevity - see test result for complete list>

Man page values

In addition, the “cipher strings” (e.g. HIGH) and the cipher suite values from the “TLS v1.2 cipher suites” section (right hand column) can be used from the openssl man page here:

https://www.openssl.org/docs/man1.0.2/apps/ciphers.html

ADH-AES128-GCM-SHA256
ADH-AES128-SHA256
ADH-AES256-GCM-SHA384
ADH-AES256-SHA256
<omitted for brevity - see test result for complete list>

NOTE: there are differences in each list.

Testing

Given the “valid” values from above, each unique value was used to set a single value for the "ssl_cipher" property.

These curl commands will work:

curl -v --tlsv1.2 {PROXY-URL}

curl -v --tlsv1 {PROXY-URL} - uses 1.2

And these will fail:

curl -v --tlsv1.0 {PROXY-URL}

curl -v --tlsv1.1 {PROXY-URL}

curl: (35) error:14077410:SSL routines:SSL23_GET_SERVER_HELLO:sslv3 alert handshake failure

Virtual Host setup using single values

curl -X PUT \
https://api.enterprise.apigee.com/v1/organizations/{{ORG}}/environments/{{ENV}}/virtualhosts/secure \
  ...
    "properties": {
        "property": [
            {
                "name": "ssl_ciphers",
                "value": "NULL-SHA256"
            }
        ]
    },
    ...
}'

Test Results

AES128-GCM-SHA256
AES128-SHA256
AES256-GCM-SHA384
AES256-SHA256
CAMELLIA128-SHA256 - Not accepted
CAMELLIA256-SHA256 - Not accepted
DHE-DSS-AES128-GCM-SHA256 - Accepted but doesnt work
DHE-DSS-AES128-SHA256 - Accepted but doesnt work
DHE-DSS-AES256-GCM-SHA384 - Accepted but doesnt work
DHE-DSS-AES256-SHA256 - Accepted but doesnt work
DHE-DSS-CAMELLIA128-SHA256 - Not accepted
DHE-DSS-CAMELLIA256-SHA256 - Not accepted
DHE-RSA-AES128-GCM-SHA256
DHE-RSA-AES128-SHA256
DHE-RSA-AES256-GCM-SHA384
DHE-RSA-AES256-SHA256
DHE-RSA-CAMELLIA128-SHA256 - Not accepted
DHE-RSA-CAMELLIA256-SHA256 - Not accepted
DHE-RSA-CHACHA20-POLY1305 - Not accepted
ECDH-ECDSA-AES128-GCM-SHA256 - Accepted but doesnt work
ECDH-ECDSA-AES128-SHA256 - Accepted but doesnt work
ECDH-ECDSA-AES256-GCM-SHA384 - Accepted but doesnt work
ECDH-ECDSA-AES256-SHA384 - Accepted but doesnt work, hangs curl
ECDH-RSA-AES128-GCM-SHA256 - Accepted but doesnt work
ECDH-RSA-AES128-SHA256 - Not accepted
ECDH-RSA-AES256-GCM-SHA384 - Accepted but doesnt work
ECDH-RSA-AES256-SHA384 - Accepted but doesnt work
ECDHE-ECDSA-AES128-GCM-SHA256 - Accepted but doesnt work
ECDHE-ECDSA-AES128-SHA256 - Accepted but doesnt work
ECDHE-ECDSA-AES256-GCM-SHA384 - Accepted but doesnt work
ECDHE-ECDSA-AES256-SHA384 - Accepted but doesnt work
ECDHE-ECDSA-CHACHA20-POLY1305 - Not accepted
ECDHE-RSA-AES128-GCM-SHA256
ECDHE-RSA-AES128-SHA256
ECDHE-RSA-AES256-GCM-SHA384
ECDHE-RSA-AES256-SHA384
ECDHE-RSA-CHACHA20-POLY1305 - Not accepted

Additional values from man page section
DH-AES128-GCM-SHA256 - Accepted but doesnt work
ADH-AES128-SHA256 - Accepted but doesnt work
ADH-AES256-GCM-SHA384 - Accepted but doesnt work
ADH-AES256-SHA256 - Accepted but doesnt work
DH-DSS-AES128-GCM-SHA256 - Accepted but doesnt work
DH-DSS-AES128-SHA256 - Accepted but doesnt work
DH-DSS-AES256-GCM-SHA384 - Accepted but doesnt work
DH-DSS-AES256-SHA256 - Accepted but doesnt work
DH-RSA-AES128-GCM-SHA256 - Accepted but doesnt work
DH-RSA-AES128-SHA256 - Accepted but doesnt work
DH-RSA-AES256-GCM-SHA384 - Accepted but doesnt work
DH-RSA-AES256-SHA256 - Accepted but doesnt work
NULL-SHA256 - Accepted but doesnt work

Virtual Host setup for all valid values

curl -X PUT \
https://api.enterprise.apigee.com/v1/organizations/{{ORG}}/environments/{{ENV}}/virtualhosts/secure \
  -H 'accept: application/json' \
  -H 'authorization: Basic ******' \
  -H 'content-type: application/json' \
  -d '{
    "hostAliases": [
        "{{ORG}}-{{ENV}}.apigee.net"
    ],
    "interfaces": [],
    "listenOptions": [],
    "name": "secure",
    "port": "443",
    "properties": {
        "property": [
            {
                "name": "ssl_ciphers",
                "value": "AES128-GCM-SHA256:AES128-SHA256:AES256-GCM-SHA384:AES256-SHA256:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES128-SHA256:DHE-RSA-AES256-GCM-SHA384:DHE-RSA-AES256-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-SHA256:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-SHA384"
            }
        ]
    },
    "retryOptions": [],
    "sSLInfo": {
        "ciphers": [],
        "clientAuthEnabled": "false",
        "enabled": "true",
        "ignoreValidationErrors": false,
        "keyAlias": "freetrial",
        "keyStore": "ref://freetrialref",
        "protocols": []
    }
}'

end.