The remote Debian host is missing a security-related update.
A vulnerability has been found in the Apache HTTPD Server : - CVE-2012-4557 A flaw was found when mod_proxy_ajp connects to a backend server that takes too long to respond. Given a specific configuration, a remote attacker could send certain requests, putting a backend server into an error state until the retry timeout expired. This could lead to a temporary denial of service. In addition, this update also adds a server side mitigation for the following issue : - CVE-2012-4929 If using SSL/TLS data compression with HTTPS in an connection to a web browser, man-in-the-middle attackers may obtain plaintext HTTP headers. This issue is known as the 'CRIME' attack. This update of apache2 disables SSL compression by default. A new SSLCompression directive has been backported that may be used to re-enable SSL data compression in environments where the 'CRIME' attack is not an issue. For more information, please refer to the SSLCompression Directive documentation.
Upgrade the apache2 packages. For the stable distribution (squeeze), these problems have been fixed in version 2.2.16-6+squeeze10.