Mitigation: Update apphost. Mitigation of httpoxy is available in lighttpd. Notified: July 12, Updated: July 12, View all 87 vendors View less vendors. Sponsored by CISA.
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Vendor Information We are not aware of further vendor information regarding this vulnerability. Vendor Information CVE Vendor References. Arista Networks, Inc. Avaya, Inc. Modify lighttpd. To strip the Proxy header from the request, add the following to lighttpd. For detailed information about mitigating httpoxy on IIS, you should head to the official Microsoft article KB , which covers the below mitigations in greater detail.
Also important to know: httpoxy does not affect any Microsoft Web Frameworks, e. But if you have installed PHP or any other third party framework on top of IIS, we recommend applying mitigation steps to protect from httpoxy attacks. You can either block requests containing a Proxy header, or clear the header. The header is safe to block, because browsers will not generally send it at all.
To block requests that contain a Proxy header the preferred solution , run the following command line. Note: appcmd. You can block any request containing a Proxy header or ban the sending client via the UrlToolkit:. See more information at the hiawatha blog.
See more information at the litespeed blog. More information can be found in this GitHub pull request. Please let us know of other places where httpoxy is found.
Contact contact httpoxy. Or create a PR or issue against the httpoxy-org repo in GitHub. RFC seems to require this meta-variable:. They cannot be distinguished from request headers according to the specification. If you need to configure the proxy of a CGI application via an environment variable, use a variable name that will never conflict with request headers.
But bear in mind that code written for the CLI context often ends up running in a SAPI eventually, particularly utility or library code. And, with open source code, that might not even be your doing. A defense-in-depth strategy that can combat httpoxy and entire classes of other security problems is to severely restrict the outgoing requests your web application can make to an absolute minimum. Using PHP as an example, because it is illustrative.
PHP has a method called getenv 1. There is a common vulnerability in many PHP libraries and applications, introduced by confusing getenv for a method that only returns environment variables.
This is the same information that getenv reads from. Note that these examples require deployment into a vulnerable environment before there is actually a vulnerability e. More complete PoC repos using Docker, and testing with an actual listener for the proxied request have been prepared under the httpoxy Github organization. Under the CGI spec, headers are provided mixed into the environment variables. The goal of the code, in most of the vulnerabilities, is to find the correct proxy to use, when auto-configuring a client for the internal HTTP request made shortly after.
Other instances of the same vulnerability are present in other languages. This indicates the vulnerability is a standard danger in CGI environments. The issue is discovered in libwww-perl and fixed. Reported by Randal L.
The issue is discovered in curl, and fixed there too albeit probably not for Windows. Reported by Cris Bailiff. Nice work Akira Tanaka!
No, Jonathan Matthews, you were exactly right! The issue is mentioned on the Apache httpd-dev mailing list. Spotted by Stefan Fritsch. Scott Geary, an engineer at Vend, found an instance of the bug in the wild. The Vend security team found the vulnerability was still exploitable in PHP, and present in many modern languages and libraries.
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