[Solar-general] el problema debian segun netcraft

Sab Jun 14 15:32:16 CEST 2008

SSL Certificates Vulnerable to OpenSSL Flaw on Debian

Netcraft's June SSL Survey has found that a significant number of SSL
certificates are affected by the Debian OpenSSL vulnerability,
including Extended Validation SSL certificates and certificates
belonging to banks.

The vulnerable certificates afford opportunities to create deceptive
sites which use apparently valid SSL certificates, giving the user the
impression that the site belongs to the certified organisation. In the
case of EV certificates, browsers will also turn the address bar
green, even though the certificate may be cloned.

>From an attacker's point of view, the main limitation is that the
browser will warn the user if the certificate common name does not
match the name used by the user to access the site, so the attacker
would need to affect the user's network or the DNS results to get a
completely seamless attack.

The following screenshot demonstrates the feasibility and
effectiveness of such an attack.

Spoofed EV SSL Certificate
Example based on vulnerable site found via Netcraft's SSL Survey database.

On the 13th May, Debian released a security advisory (also described
in CVE-2008-0166) announcing a vulnerability in Debian's OpenSSL
package, which made it possible to discover private keys from public
SSL and SSH keys. The issue affects all versions of OpenSSL on
Debian-based operating systems over the course of two years — ever
since two lines of code were commented out to prevent compilers
displaying warnings about the use of uninitialized data.

The removal of these two lines of code vastly decreases the entropy of
the seed used by the pseudo-random number generator in OpenSSL, making
it easier to predict the random numbers generated by OpenSSL. This
makes it easy for remote attackers to conduct offline brute force
attacks against the cryptographic keys used in SSL certificates
generated on vulnerable systems. All SSL and SSH keys generated on
Debian-based operating systems since September 2006 may be affected.
Affected operating systems include Ubuntu, Kubuntu, Knoppix, Grml and
the Xandros Linux distribution used by the popular Asus Eee PC.

Spoofed EV SSL Certificate

HD Moore has published an analysis of the Debian OpenSSL issue at
Metasploit, noting how the keys are tied to the process ID. Using 31
Xeon cores clocked at 2.33GHz, Moore was able to generate all 1024-bit
DSA and 2048-bit RSA keys for x86 architectures in only 2 hours, and
all 4096-bit RSA keys in about 6 hours.

Although a number of certificate authorities have offered free
replacement certificates to customers affected by the Debian OpenSSL
vulnerability, it has been reported that they have not been getting a
big response. Comodo is offering a free replacement SSL certificate to
any affected business, regardless of their original provider, while
VeriSign is offering free reissuance for both SSL certificates and
code signing certificates. GeoTrust a! nd Thawte also offer free SSL
certificate reissuance, and RapidSSL certificates can be renewed for
free at GeoTrust's website.
digg_window = 'new'; digg_skin = 'compact'; digg_url =
'http://news.netcraft.com/archives/2008/06/12/ssl_certificates_vulnerable_to_openssl_flaw_on_debian.html';
Posted by Paul Mutton at 04:20 PM UTC on Jun 12, 2008 in Security |
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Diego Saravia
Diego.Saravia en gmail.com
NO FUNCIONA->dsa en unsa.edu.ar