Re: Potential HTTP Header Injection in Apache HTTPClient

[Kurt Seifried <kseifried () redhat com>]

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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, As

Has anyone investigated this/can comment on this? thanks.

- -- 
Kurt Seifried Red Hat Security Response Team (SRT)
PGP: 0x5E267993 A90B F995 7350 148F 66BF 7554 160D 4553 5E26 7993

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