CVE-2016-5387

The Apache HTTP Server through 2.4.23 follows RFC 3875 section 4.1.18 and therefore does not protect applications from the presence of untrusted client data in the HTTP_PROXY environment variable, which might allow remote attackers to redirect an application's outbound HTTP traffic to an arbitrary proxy server via a crafted Proxy header in an HTTP request, aka an "httpoxy" issue. NOTE: the vendor states "This mitigation has been assigned the identifier CVE-2016-5387"; in other words, this is not a CVE ID for a vulnerability.

The Apache HTTP Server through 2.4.23 follows RFC 3875 section 4.1.18 and therefore does not protect applications from the presence of untrusted client data in the HTTP_PROXY environment variable, which might allow remote attackers to redirect an application's outbound HTTP traffic to an arbitrary proxy server via a crafted Proxy header in an HTTP request, aka an "httpoxy" issue. NOTE: the vendor states "This mitigation has been assigned the identifier CVE-2016-5387"; in other words, this is not a CVE ID for a vulnerability.

It was discovered that httpd used the value of the Proxy header from HTTP requests to initialize the HTTP_PROXY environment variable for CGI scripts, which in turn was incorrectly used by certain HTTP client implementations to configure the proxy for outgoing HTTP requests. A remote attacker could possibly use this flaw to redirect HTTP requests performed by a CGI script to an attacker-controlled proxy via a malicious HTTP request (CVE-2016-5387).

This update removes the setting of the HTTP_PROXY environment value. This works around the httproxy vulnerability (aka CVE-2016-5387)

These are all security issues fixed in the apache2-2.4.49-1.1 package on the GA media of openSUSE Tumbleweed.

This update for apache2 fixes the following issues:

• It used to be possible to set an arbitrary $HTTP_PROXY environment variable for request handlers -- like CGI scripts -- by including a specially crafted HTTP header in the request (CVE-2016-5387). As a result, these server components would potentially direct all their outgoing HTTP traffic through a malicious proxy server. This patch fixes the issue: the updated Apache server ignores such HTTP headers and never sets $HTTP_PROXY for sub-processes (unless a value has been explicitly configured by the administrator in the configuration file). (bsc#988488)

This update for apache2 fixes the following issues:

• It used to be possible to set an arbitrary $HTTP_PROXY environment variable for request handlers -- like CGI scripts -- by including a specially crafted HTTP header in the request (CVE-2016-5387). As a result, these server components would potentially direct all their outgoing HTTP traffic through a malicious proxy server. This patch fixes the issue: the updated Apache server ignores such HTTP headers and never sets $HTTP_PROXY for sub-processes (unless a value has been explicitly configured by the administrator in the configuration file). (bsc#988488)

This update for apache2 fixes the following issues:

• It used to be possible to set an arbitrary $HTTP_PROXY environment variable for request handlers -- like CGI scripts -- by including a specially crafted HTTP header in the request (CVE-2016-5387). As a result, these server components would potentially direct all their outgoing HTTP traffic through a malicious proxy server. This patch fixes the issue: the updated Apache server ignores such HTTP headers and never sets $HTTP_PROXY for sub-processes (unless a value has been explicitly configured by the administrator in the configuration file). (bsc#988488)

• Ignore SIGINT signal in child processes. This fixes a race condition in signals handling when httpd is running on foreground and the user hits ctrl+c. (bsc#970391)

• Don't put the backend in error state (by default) when 500/503 is overridden. (bsc#951692)

• Remove obsolete /usr/share/apache2/rc.apache2 sample script. (bsc#973381)

It was discovered that the Apache HTTP Server would set the HTTP_PROXY environment variable based on the contents of the Proxy header from HTTP requests. A remote attacker could possibly use this issue in combination with CGI scripts that honour the HTTP_PROXY variable to redirect outgoing HTTP requests.