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Ubuntu Security Notice USN-3279-1
May 09, 2017

apache2 vulnerabilities
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 16.10
- Ubuntu 16.04 LTS
- Ubuntu 14.04 LTS

Summary:

Several security issues were fixed in Apache HTTP Server.

Software Description:
- apache2: Apache HTTP server

Details:

It was discovered that the Apache mod_session_crypto module was encrypting
data and cookies using either CBC or ECB modes. A remote attacker could
possibly use this issue to perform padding oracle attacks. (CVE-2016-0736)

Maksim Malyutin discovered that the Apache mod_auth_digest module
incorrectly handled malicious input. A remote attacker could possibly use
this issue to cause Apache to crash, resulting in a denial of service.
(CVE-2016-2161)

David Dennerline and RA(c)gis Leroy discovered that the Apache HTTP Server
incorrectly handled unusual whitespace when parsing requests, contrary to
specifications. When being used in combination with a proxy or backend
server, a remote attacker could possibly use this issue to perform an
injection attack and pollute cache. This update may introduce compatibility
issues with clients that do not strictly follow HTTP protocol
specifications. A new configuration option "HttpProtocolOptions Unsafe" can
be used to revert to the previous unsafe behaviour in problematic
environments. (CVE-2016-8743)

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 16.10:
  apache2-bin                     2.4.18-2ubuntu4.1

Ubuntu 16.04 LTS:
  apache2-bin                     2.4.18-2ubuntu3.2

Ubuntu 14.04 LTS:
  apache2-bin                     2.4.7-1ubuntu4.14

In general, a standard system update will make all the necessary changes.

References:
  http://www.ubuntu.com/usn/usn-3279-1
  CVE-2016-0736, CVE-2016-2161, CVE-2016-8743

Package Information:
  https://launchpad.net/ubuntu/+source/apache2/2.4.18-2ubuntu4.1
  https://launchpad.net/ubuntu/+source/apache2/2.4.18-2ubuntu3.2
  https://launchpad.net/ubuntu/+source/apache2/2.4.7-1ubuntu4.14