Re: Conficker scanning with nmap

[Brandon Enright <bmenrigh () ucsd edu>]

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On Wed, 1 Apr 2009 10:34:52 +0200 or thereabouts Lionel Cons
<lionel.cons () cern ch> wrote:

> Brandon Enright <bmenrigh () ucsd edu> writes:
> > evp_enc.c(282): OpenSSL internal error, assertion failed: inl > 0
>
> Brandon,
>
> I managed to isolate the problem. It lies in nse_openssl.cc, in the
> function l_encrypt which is sometimes called with an empty string.
> In this case, data_len is 0 and the following:
>
>   EVP_EncryptUpdate( &cipher_ctx, out, &out_len, data, data_len )
>
> triggers the fatal error from OpenSSL:
>
>   evp_enc.c(261): OpenSSL internal error, assertion failed: inl > 0
>
> Cheers,
>
> Lionel

Excellent digging.  I'll probably be able to work backwards from here
to figure out why tomorrow.

I'm assuming that the error is triggered in "NSE: SMB: Creating NTLMv1
response".  Ron might be able to think of a case where this would happen too.

I've never been able to reproduce the problem myself and I've tested
against a *lot* of machines/devices so either the version of OpenSSL
I'm running doesn't have the same assert() or the error condition to
trigger data_len = 0 is somewhat involved.

Brandon



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