The Apache HTTP Server is a popular Web server.
A flaw was found in the way the TLS/SSL (Transport Layer Security/Secure Sockets Layer) protocols handle session renegotiation. A man-in-the-middle attacker could use this flaw to prefix arbitrary plain text to a client's session (for example, an HTTPS connection to a website). This could force the server to process an attacker's request as if authenticated using the victim's credentials. This update partially mitigates this flaw for SSL sessions to HTTP servers using mod_ssl by rejecting client-requested renegotiation. (CVE-2009-3555)
Note: This update does not fully resolve the issue for HTTPS servers. An attack is still possible in configurations that require a server-initiated renegotiation. Refer to the following Knowledgebase article for further information: http://kbase.redhat.com/faq/docs/DOC-20491
A NULL pointer dereference flaw was found in the Apache mod_proxy_ftp module. A malicious FTP server to which requests are being proxied could use this flaw to crash an httpd child process via a malformed reply to the EPSV or PASV commands, resulting in a limited denial of service. (CVE-2009-3094)
A second flaw was found in the Apache mod_proxy_ftp module. In a reverse proxy configuration, a remote attacker could use this flaw to bypass intended access restrictions by creating a carefully-crafted HTTP Authorization header, allowing the attacker to send arbitrary commands to the FTP server. (CVE-2009-3095)
All httpd users should upgrade to these updated packages, which contain backported patches to correct these issues. After installing the updated packages, the httpd daemon must be restarted for the update to take effect.