[Pkg-openssl-devel] Bug#529221: Bug#529221: Netscape/OpenSSL Cipher Forcing Bug

[Kurt Roeckx]

Hi,

It seems that some other vendors like redhat have already addressed
this years ago, but there doesn't seem to be a CVE for it.  Could
someone get a CVE assigned to this?

I don't plan to make the same change to the header, since
we would need to rebuild everything to get that option turned
off.  I plan to just change the library to make that option do
nothing.


Kurt

On Mon, May 18, 2009 at 08:49:39AM +0200, Jürgen Heil wrote:
> Hi!
> 
> We ran into this bug during our last Qualys security scan. It is reported as
> a Level 3 Vulnerability and as such not compliant to the Payment Card Data
> Security Standard (PCI DSS) as required by Visa and Mastercard. 
> 
> =============================================
> = Here is the Qualys vulnerability description:
> ==
> 
> # Diagnosis
> Netscape's SSLv3 implementation had a bug where if a SSLv3 connection is
> initially established, the first available cipher is used. If a session is
> resumed, a different cipher may be chosen if it appears in the passed cipher
> list before the session's current cipher. This bug can be used to change
> ciphers on the server. OpenSSL contains this bug if the
> SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG option is enabled during runtime.
> This option was introduced for compatibility reasons. The problem arises
> when different applications using OpenSSL's libssl library enable all
> compatibility options including SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG,
> thus enabling the bug.
> 
> # Consequence
> A malicious legitimate client can enforce a ciphersuite not supported by the
> server to be used for a session between the client and the server. This can
> result in disclosure of sensitive information.
> 
> # Solution
> This problem can be fixed by disabling the SSL OP NETSCAPE REUSE
> CIPHER_CHANGE_BUG option from the options list of OpenSSL's libssl library.
> This can be done by replacing the SSL OP ALL definition in the openssl/ssl.h
> file with the following line:
> 
> #define SSL OP ALL (0x00000FFFL^SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG)
> 
> Unfortunately there is no CVE number. I've found a discussion of this bug on
> the OpenSSL developer mailing list.
> http://marc.info/?l=openssl-dev&m=109532567028570&w=2
> 
> Could you be so kind to address this issue in a future openssl/libssl0.9.8
> release?
> 
> Thank you very much!
> 
> Best regards,
> 
> Juergen Heil
> 
> 
> 
> 
> 
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