mynews.apple.com, Resolved, HTTP Header Injection, Location Response Splitting, CWE-113, CRLF

HTTP Header Injection, Location Response Splitting reported to Apple Product Security on July 20, 2011 and noted resolved on February 21, 2012 via URL http://support.apple.com/kb/ht1318.

Summary

Severity:	High
Confidence:	Certain
Host:	http://mynews.apple.com
Path:	/cgi-bin/WebObjects/Subscriptions.woa/27/wo/2b0nLrEPFOLhjUyNTIlzqM/0.1.21.3.3

Issue detail

The value of the CookieURLDescSubs cookie is copied into the location response header. The payload 6b61f%0d%0a9c98044096b was submitted in the CookieURLDescSubs cookie. This caused a response containing an injected HTTP header.

Issue background

HTTP header injection vulnerabilities arise when user-supplied data is copied into a response header in an unsafe way. If an attacker can inject newline characters into the header, then they can inject new HTTP headers and also, by injecting an empty line, break out of the headers into the message body and write arbitrary content into the application's response.

Various kinds of attack can be delivered via HTTP header injection vulnerabilities. Any attack that can be delivered via cross-site scripting can usually be delivered via header injection, because the attacker can construct a request which causes arbitrary JavaScript to appear within the response body. Further, it is sometimes possible to leverage header injection vulnerabilities to poison the cache of any proxy server via which users access the application. Here, an attacker sends a crafted request which results in a "split" response containing arbitrary content. If the proxy server can be manipulated to associate the injected response with another URL used within the application, then the attacker can perform a "stored" attack against this URL which will compromise other users who request that URL in future.