oss-sec mailing list archives
Re: Potential HTTP Header Injection in Apache HTTPClient
From: David Jorm <djorm () redhat com>
Date: Fri, 15 Feb 2013 13:08:07 +1000
On 02/13/2013 07:54 PM, Kurt Seifried wrote:
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 01/10/2013 07:38 AM, chevalier 3as wrote:Hi, As I'm not sure if this is a vulnerability or simply a 'feature', I'm posting the details for more information. The addRequestHeader method of the Apache HTTPClient module version 3.x seems to allow the injection of more than a header (potentilally the latest version 4.x too for addHeader method): Using the following code, it includes a third header in the request: HttpClient client = new HttpClient(); PostMethod method = new PostMethod("http://www.google.fr"); method.addRequestHeader("header1", "value1\r\nheader3: value3"); method.addRequestHeader("header2","value2"); The real risk is adding a second request using a similar code: req.addRequestHeader("Content-Length:0\r\n\r\n" + "POST\t/anotherpath\tHTTP/1.1\r\n" + "Host:host\r\n" + "Referer:faked\r\n" + "User-Agent:faked\r\n" + "Content-Type:faked\r\n" + "Content-Length:3\r\n" + "\r\n" + "foo\n", "bar"); Because of the Content-Length header, the sever will consider it as a seperate request. Iis this an expected behavior ? if so developpers should be aware of the risk letting a user input values. A similar advisory for Flash is available here: http://www.rapid7.com/resources/advisories/R7-0026.jsp My 2 cents, AsHas anyone investigated this/can comment on this? thanks.
I do not think this qualifies as a vulnerability. The addRequestHeader method isn't stripping out CRLF, allowing for a potential header splitting attack if an application passes unsanitized user input to addRequestHeader. The onus should be on the application to sanitize user input appropriately. If we called this a vulnerability, then we'd have to say a database interface that lets you pass an SQL string might allow for SQL injection, or something that lets you print a string to the body of a HTTP response might allow for XSS.
Having an optional parameter to addRequestHeader to sanitize CRLF values might be a nice feature, but I'd call it a feature request rather than a vulnerability.
Thanks David
Current thread:
- Potential HTTP Header Injection in Apache HTTPClient chevalier 3as (Jan 10)
- Re: Potential HTTP Header Injection in Apache HTTPClient Kurt Seifried (Feb 13)
- Re: Potential HTTP Header Injection in Apache HTTPClient David Jorm (Feb 14)
- Re: Potential HTTP Header Injection in Apache HTTPClient Kurt Seifried (Feb 13)