Re: Using weak ciphers in OpenSSL v 1.1.0e client

[gerritvn <gerritvn@xxxxxxxxxxx>]

Thank you Ben, but I am afraid it does not work unless I'm doing something wrong.

Here is a code snippet:
int CSSL::createCTX(SSL_CTX **ppctx, int &extError)
{
    X509_NAME *xn;
    SSL *ssl;
    X509 *pX509;
    POSITION pos;
    TCHAR name[256], *cert_file = NULL, *CAfile, certInfo[512] = _T("");
    int len, err;
    char *CApath = NULL, caFile[256];
    extError = 0;

    if(!(*ppctx = SSL_CTX_new(SSLv23_client_method()))) {
        ::ShowErrorMsg((DWORD)m_pConfig, 0, 0, SSL_ERROR_CAPTION, _T("Error creating ctx object - SSL_CTX_new() failed"));
        extError = _SSL_CTX_NEW_FAILED;
        return _SSL_ERROR;
    }

    SSL_CTX_set_options(*ppctx, 0);
    SSL_CTX_set_security_level(*ppctx, 0);    // for compatibility with weak ciphers
.
.

Gerrit van Niekerk
GP van Niekerk Ondernemings BK
Roosstraat 211, Meyerspark, 0184, South Africa
Tel: +27(12)8036501 Fax SA: 086 537 4131
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Cell: +27(73)6891370
Email: [hidden email], [hidden email]
Web: http://www.gpvno.co.za

On Wed, Jun 7, 2017 at 6:16 PM, OpenSSL - User mailing list [via OpenSSL] <[hidden email]> wrote:

On 06/07/2017 11:13 AM, gerritvn wrote:

We are using OpenSSL in a terminal emulation product.
We recently upgraded from OpenSSL v 1.0.2g to OpenSSL v 1.1.0e.
Some servers we connect to do not support any of the strong ciphers which
are compiled by default in OpenSSL v 1.1.0e and returns an alert with
"handshake error". 
We recompiled with the option "enable-weak-ssl-ciphers", but that does not
solve the problem.
With OpenSSL v 1.0.2g one specific server selected the Cipher Suite:
TLS_RSA_WITH_3DES_EDE_CBC_SHA (0x000a) which is shown as DES-CBC3-SHA by
OpenSSL
Listing ciphers with our OpenSSL 1.1.0e "enable-weak-ssl-ciphers" build with
the command:
openssl ciphers -v "ALL:@SECLEVEL=0" 
shows this entry:
DES-CBC3-SHA            SSLv3 Kx=RSA      Au=RSA  Enc=3DES(168) Mac=SHA1
This cipher is, however, not offered in the Client Hello when our client
opens the connection.

What do we need to add to our program to get our client to offer the weak
ciphers as well as the strong ones?

https://www.openssl.org/docs/man1.1.0/ssl/SSL_CTX_set_security_level.html

-Ben

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