[advisory] httpd Timeout detection flaw (mod_proxy_http) CVE-2010-2068

Vulnerability; httpd Timeout detection flaw (mod_proxy_http) CVE-2010-2068

Classification; important

Description;

A timeout detection flaw in the httpd mod_proxy_http module causes
proxied response to be sent as the response to a different request,
and potentially served to a different client, from the HTTP proxy
pool worker pipeline.

This may represent a confidential data revealing flaw.

This affects only Netware, Windows or OS2 builds of httpd version
2.2.9 through 2.2.15, 2.3.4-alpha and 2.3.5-alpha, when the proxy
worker pools have been enabled.  Earlier 2.2, 2.0 and 1.3 releases
were not affected.

Acknowledgements;

We would like to thank Loren Anderson for the thorough research
and reporting of this flaw.

Mitigation;

Apply any one of the following mitigations to avert the possibility
of confidential information disclosure.

* Do not load mod_proxy_http.

* Do not configure/enable any http proxy worker pools with ProxySet
  or ProxyPass optional arguments.

* The straightforward workaround to disable mod_proxy_http's reuse
  of backend connection pipelines is to set the following global
  directive;

    SetEnv proxy-nokeepalive 1

* Replace mod_proxy_http.so with a patched version, for source code
  see http://www.apache.org/dist/httpd/patches/apply_to_2.2.15/ or
  http://www.apache.org/dist/httpd/patches/apply_to_2.3.5/ and for
  binaries see the http://www.apache.org/dist/httpd/binaries/ tree
  for win32 or netware, as appropriate.

* Upgrade to Apache httpd 2.2.16 or higher, once released.  There
  is no tentative release date scheduled.

Update Released; 11th June 2010