Debian: DSA-2141-1 Critical: OpenSSL Insecure Renegotiation Threat

Marsh Ray, Steve Dispensa, and Martin Rex discovered a flaw in the TLS
and SSLv3 protocols. If an attacker could perform a man in the middle
attack at the start of a TLS connection, the attacker could inject
arbitrary content at the beginning of the user's session. This update
adds backported support for the new RFC5746 renegotiation extension
which fixes this issue.

If openssl is used in a server application, it will by default no
longer accept renegotiation from clients that do not support the
RFC5746 secure renegotiation extension. A separate advisory will add
RFC5746 support for nss, the security library used by the iceweasel
web browser. For apache2, there will be an update which allows to
re-enable insecure renegotiation.

This version of openssl is not compatible with older versions of tor.
You have to use at least tor version 0.2.1.26-1~lenny+1, which has
been included in the point release 5.0.7 of Debian stable.

Currently we are not aware of other software with similar compatibility
problems.


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