The value of the mc request parameter is copied into the Location response header. The payload 69389%0d%0aa34d9949d31 was submitted in the mc parameter. 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.
Issue remediation
If possible, applications should avoid copying user-controllable data into HTTP response headers. If this is unavoidable, then the data should be strictly validated to prevent header injection attacks. In most situations, it will be appropriate to allow only short alphanumeric strings to be copied into headers, and any other input should be rejected. At a minimum, input containing any characters with ASCII codes less than 0x20 should be rejected.
Request
GET /?mc=69389%0d%0aa34d9949d31 HTTP/1.1 Host: maildomain.web.de Connection: keep-alive User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/534.16 (KHTML, like Gecko) Chrome/10.0.648.151 Safari/534.16 Accept: application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5 Accept-Encoding: gzip,deflate,sdch Accept-Language: en-US,en;q=0.8 Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3 Cookie: ns_sample=55; emos_webde_sid=AAABLtSNbCqzQSUHnTM4d48JcGoTXg3o:2:AAABLtSSgAj1py4TQXzdSyZvs0NYeL8W:1300646494216; emos_webde_vid=AAABLtSLhHmpABw4zP5PeVODs7dkXu9_:2:AAABLtSNbCqzQSUHnTM4d48JcGoTXg3o:1300646161450:0:true:1; emos1und1d1_jcsid=AAABLtSSgBYgxv1GXnhi2VG16deIh1cG:1:AAABLtSSgBb*PZ34FMHU96KUXqL6aQTD:1300646494230; emos1und1d1_jcvid=AAABLtSSgBYgxv1GXnhi2VG16deIh1cG:1:AAABLtSSgBYgxv1GXnhi2VG16deIh1cG:1300646494230:0:false:10
Response
HTTP/1.1 302 Found Date: Sun, 20 Mar 2011 18:42:17 GMT Server: Apache/2.0.63 (Unix) mod_ssl/2.0.63 OpenSSL/0.9.8h Location: /extern/?si=NvAvynWV8cCjn145XEt*002&mc=69389 a34d9949d31 Cache-control: no-store,max-age=0 Vary: Accept-Encoding Connection: close Content-Type: text/html Content-Length: 115
<HTML><HEAD><TITLE>Found</TITLE></HEAD><BODY><H1>Found</H1>This document has moved to a new location.</BODY></HTML>
2. Cross-site scripting (reflected)previousnext There are 3 instances of this issue:
Reflected cross-site scripting vulnerabilities arise when data is copied from a request and echoed into the application's immediate response in an unsafe way. An attacker can use the vulnerability to construct a request which, if issued by another application user, will cause JavaScript code supplied by the attacker to execute within the user's browser in the context of that user's session with the application.
The attacker-supplied code can perform a wide variety of actions, such as stealing the victim's session token or login credentials, performing arbitrary actions on the victim's behalf, and logging their keystrokes.
Users can be induced to issue the attacker's crafted request in various ways. For example, the attacker can send a victim a link containing a malicious URL in an email or instant message. They can submit the link to popular web sites that allow content authoring, for example in blog comments. And they can create an innocuous looking web site which causes anyone viewing it to make arbitrary cross-domain requests to the vulnerable application (using either the GET or the POST method).
The security impact of cross-site scripting vulnerabilities is dependent upon the nature of the vulnerable application, the kinds of data and functionality which it contains, and the other applications which belong to the same domain and organisation. If the application is used only to display non-sensitive public content, with no authentication or access control functionality, then a cross-site scripting flaw may be considered low risk. However, if the same application resides on a domain which can access cookies for other more security-critical applications, then the vulnerability could be used to attack those other applications, and so may be considered high risk. Similarly, if the organisation which owns the application is a likely target for phishing attacks, then the vulnerability could be leveraged to lend credibility to such attacks, by injecting Trojan functionality into the vulnerable application, and exploiting users' trust in the organisation in order to capture credentials for other applications which it owns. In many kinds of application, such as those providing online banking functionality, cross-site scripting should always be considered high risk.
Issue remediation
In most situations where user-controllable data is copied into application responses, cross-site scripting attacks can be prevented using two layers of defences:
Input should be validated as strictly as possible on arrival, given the kind of content which it is expected to contain. For example, personal names should consist of alphabetical and a small range of typographical characters, and be relatively short; a year of birth should consist of exactly four numerals; email addresses should match a well-defined regular expression. Input which fails the validation should be rejected, not sanitised.
User input should be HTML-encoded at any point where it is copied into application responses. All HTML metacharacters, including < > " ' and =, should be replaced with the corresponding HTML entities (< > etc).
In cases where the application's functionality allows users to author content using a restricted subset of HTML tags and attributes (for example, blog comments which allow limited formatting and linking), it is necessary to parse the supplied HTML to validate that it does not use any dangerous syntax; this is a non-trivial task.
The value of the mc request parameter is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload 7ac13"><a>35bd5f6b2af was submitted in the mc parameter. This input was echoed unmodified in the application's response.
This behaviour demonstrates that it is possible to inject new HTML tags into the returned document. An attempt was made to identify a full proof-of-concept attack for injecting arbitrary JavaScript but this was not successful. You should manually examine the application's behaviour and attempt to identify any unusual input validation or other obstacles that may be in place.
Note that a redirection occurred between the attack request and the response containing the echoed input. It is necessary to follow this redirection for the attack to succeed. When the attack is carried out via a browser, the redirection will be followed automatically.
Request
GET /?mc=hp@fm@reiter.produkte@freemail7ac13"><a>35bd5f6b2af HTTP/1.1 Host: maildomain.web.de Connection: keep-alive User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/534.16 (KHTML, like Gecko) Chrome/10.0.648.151 Safari/534.16 Accept: application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5 Accept-Encoding: gzip,deflate,sdch Accept-Language: en-US,en;q=0.8 Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3 Cookie: ns_sample=55; emos_webde_sid=AAABLtSNbCqzQSUHnTM4d48JcGoTXg3o:2:AAABLtSSgAj1py4TQXzdSyZvs0NYeL8W:1300646494216; emos_webde_vid=AAABLtSLhHmpABw4zP5PeVODs7dkXu9_:2:AAABLtSNbCqzQSUHnTM4d48JcGoTXg3o:1300646161450:0:true:1; emos1und1d1_jcsid=AAABLtSSgBYgxv1GXnhi2VG16deIh1cG:1:AAABLtSSgBb*PZ34FMHU96KUXqL6aQTD:1300646494230; emos1und1d1_jcvid=AAABLtSSgBYgxv1GXnhi2VG16deIh1cG:1:AAABLtSSgBYgxv1GXnhi2VG16deIh1cG:1300646494230:0:false:10
Response (redirected)
HTTP/1.1 200 OK Date: Sun, 20 Mar 2011 18:53:10 GMT Server: Apache/2.0.63 (Unix) mod_ssl/2.0.63 OpenSSL/0.9.8l Expires: Wed, 01 Jan 1997 00:00:00 GMT Pragma: no-cache Cache-control: no-store,max-age=0,post-check=0,pre-check=0 Vary: Accept-Encoding Connection: close Content-Type: text/html; charset=iso-8859-1 Content-Length: 22628
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="de" lang="de"> <head>
The value of the mc request parameter is copied into a JavaScript string which is encapsulated in single quotation marks. The payload 13688'%3b1a19b92007f was submitted in the mc parameter. This input was echoed as 13688';1a19b92007f in the application's response.
This behaviour demonstrates that it is possible to terminate the JavaScript string into which our data is being copied. An attempt was made to identify a full proof-of-concept attack for injecting arbitrary JavaScript but this was not successful. You should manually examine the application's behaviour and attempt to identify any unusual input validation or other obstacles that may be in place.
Note that a redirection occurred between the attack request and the response containing the echoed input. It is necessary to follow this redirection for the attack to succeed. When the attack is carried out via a browser, the redirection will be followed automatically.
Remediation detail
Echoing user-controllable data within a script context is inherently dangerous and can make XSS attacks difficult to prevent. If at all possible, the application should avoid echoing user data within this context.
Request
GET /?mc=hp@fm@reiter.produkte@freemail13688'%3b1a19b92007f HTTP/1.1 Host: maildomain.web.de Connection: keep-alive User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/534.16 (KHTML, like Gecko) Chrome/10.0.648.151 Safari/534.16 Accept: application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5 Accept-Encoding: gzip,deflate,sdch Accept-Language: en-US,en;q=0.8 Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3 Cookie: ns_sample=55; emos_webde_sid=AAABLtSNbCqzQSUHnTM4d48JcGoTXg3o:2:AAABLtSSgAj1py4TQXzdSyZvs0NYeL8W:1300646494216; emos_webde_vid=AAABLtSLhHmpABw4zP5PeVODs7dkXu9_:2:AAABLtSNbCqzQSUHnTM4d48JcGoTXg3o:1300646161450:0:true:1; emos1und1d1_jcsid=AAABLtSSgBYgxv1GXnhi2VG16deIh1cG:1:AAABLtSSgBb*PZ34FMHU96KUXqL6aQTD:1300646494230; emos1und1d1_jcvid=AAABLtSSgBYgxv1GXnhi2VG16deIh1cG:1:AAABLtSSgBYgxv1GXnhi2VG16deIh1cG:1300646494230:0:false:10
Response (redirected)
HTTP/1.1 200 OK Date: Sun, 20 Mar 2011 18:42:12 GMT Server: Apache/2.0.63 (Unix) mod_ssl/2.0.63 OpenSSL/0.9.8h Expires: Wed, 01 Jan 1997 00:00:00 GMT Pragma: no-cache Cache-control: no-store,max-age=0,post-check=0,pre-check=0 Vary: Accept-Encoding Connection: close Content-Type: text/html; charset=iso-8859-1 Content-Length: 22565
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="de" lang="de"> <head>
The value of the mc request parameter is copied into a JavaScript string which is encapsulated in single quotation marks. The payload bc3dc'%3balert(1)//55453b69201 was submitted in the mc parameter. This input was echoed as bc3dc';alert(1)//55453b69201 in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
Remediation detail
Echoing user-controllable data within a script context is inherently dangerous and can make XSS attacks difficult to prevent. If at all possible, the application should avoid echoing user data within this context.
Request
GET /extern/?si=-gDyMoImWgeBWMcZ8IW*001&mc=hp@fm@reiter.produkte@freemailbc3dc'%3balert(1)//55453b69201 HTTP/1.1 Host: maildomain.web.de Connection: keep-alive User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/534.16 (KHTML, like Gecko) Chrome/10.0.648.151 Safari/534.16 Accept: application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5 Accept-Encoding: gzip,deflate,sdch Accept-Language: en-US,en;q=0.8 Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3 Cookie: emos_webde_sid=AAABLtSNbCqzQSUHnTM4d48JcGoTXg3o:2:AAABLtSSgAj1py4TQXzdSyZvs0NYeL8W:1300646494216; emos_webde_vid=AAABLtSLhHmpABw4zP5PeVODs7dkXu9_:2:AAABLtSNbCqzQSUHnTM4d48JcGoTXg3o:1300646161450:0:true:1; emos1und1d1_jcsid=AAABLtSSgBYgxv1GXnhi2VG16deIh1cG:1:AAABLtSSgBb*PZ34FMHU96KUXqL6aQTD:1300646494230; emos1und1d1_jcvid=AAABLtSSgBYgxv1GXnhi2VG16deIh1cG:1:AAABLtSSgBYgxv1GXnhi2VG16deIh1cG:1300646494230:0:false:10; NGCount=X0712311Ecvg017X; psid=babhddd.1300646537.2912.d7ftmlktr3.73.ggc; ns_sample=55
Response
HTTP/1.1 200 OK Date: Sun, 20 Mar 2011 18:42:29 GMT Server: Apache/2.0.63 (Unix) mod_ssl/2.0.63 OpenSSL/0.9.8h Expires: Wed, 01 Jan 1997 00:00:00 GMT Pragma: no-cache Cache-control: no-store,max-age=0,post-check=0,pre-check=0 Vary: Accept-Encoding Connection: close Content-Type: text/html; charset=iso-8859-1 Content-Length: 22214
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="de" lang="de"> <head>
When a web browser makes a request for a resource, it typically adds an HTTP header, called the "Referer" header, indicating the URL of the resource from which the request originated. This occurs in numerous situations, for example when a web page loads an image or script, or when a user clicks on a link or submits a form.
If the resource being requested resides on a different domain, then the Referer header is still generally included in the cross-domain request. If the originating URL contains any sensitive information within its query string, such as a session token, then this information will be transmitted to the other domain. If the other domain is not fully trusted by the application, then this may lead to a security compromise.
You should review the contents of the information being transmitted to other domains, and also determine whether those domains are fully trusted by the originating application.
Today's browsers may withhold the Referer header in some situations (for example, when loading a non-HTTPS resource from a page that was loaded over HTTPS, or when a Refresh directive is issued), but this behaviour should not be relied upon to protect the originating URL from disclosure.
Note also that if users can author content within the application then an attacker may be able to inject links referring to a domain they control in order to capture data from URLs used within the application.
Issue remediation
The application should never transmit any sensitive information within the URL query string. In addition to being leaked in the Referer header, such information may be logged in various locations and may be visible on-screen to untrusted parties.
When an application includes a script from an external domain, this script is executed by the browser within the security context of the invoking application. The script can therefore do anything that the application's own scripts can do, such as accessing application data and performing actions within the context of the current user.
If you include a script from an external domain, then you are trusting that domain with the data and functionality of your application, and you are trusting the domain's own security to prevent an attacker from modifying the script to perform malicious actions within your application.
Issue remediation
Scripts should not be included from untrusted domains. If you have a requirement which a third-party script appears to fulfil, then you should ideally copy the contents of that script onto your own domain and include it from there. If that is not possible (e.g. for licensing reasons) then you should consider reimplementing the script's functionality within your own code.
The TRACE method is designed for diagnostic purposes. If enabled, the web server will respond to requests which use the TRACE method by echoing in its response the exact request which was received.
Although this behaviour is apparently harmless in itself, it can sometimes be leveraged to support attacks against other application users. If an attacker can find a way of causing a user to make a TRACE request, and can retrieve the response to that request, then the attacker will be able to capture any sensitive data which is included in the request by the user's browser, for example session cookies or credentials for platform-level authentication. This may exacerbate the impact of other vulnerabilities, such as cross-site scripting.
Issue remediation
The TRACE method should be disabled on the web server.
The file robots.txt is used to give instructions to web robots, such as search engine crawlers, about locations within the web site which robots are allowed, or not allowed, to crawl and index.
The presence of the robots.txt does not in itself present any kind of security vulnerability. However, it is often used to identify restricted or private areas of a site's contents. The information in the file may therefore help an attacker to map out the site's contents, especially if some of the locations identified are not linked from elsewhere in the site. If the application relies on robots.txt to protect access to these areas, and does not enforce proper access control over them, then this presents a serious vulnerability.
Issue remediation
The robots.txt file is not itself a security threat, and its correct use can represent good practice for non-security reasons. You should not assume that all web robots will honour the file's instructions. Rather, assume that attackers will pay close attention to any locations identified in the file. Do not rely on robots.txt to provide any kind of protection over unauthorised access.
Request
GET /robots.txt HTTP/1.0 Host: maildomain.web.de
Response
HTTP/1.1 200 OK Date: Sun, 20 Mar 2011 18:41:14 GMT Server: Apache/2.0.63 (Unix) mod_ssl/2.0.63 OpenSSL/0.9.8h Expires: Wed, 01 Jan 1997 00:00:00 GMT Pragma: no-cache Cache-control: no-store,max-age=0,post-check=0,pre-check=0 Content-Length: 82 Vary: Accept-Encoding Connection: close Content-Type: text/plain
Unless directed otherwise, browsers may store a local cached copy of content received from web servers. Some browsers, including Internet Explorer, cache content accessed via HTTPS. If sensitive information in application responses is stored in the local cache, then this may be retrieved by other users who have access to the same computer at a future time.
Issue remediation
The application should return caching directives instructing browsers not to store local copies of any sensitive data. Often, this can be achieved by configuring the web server to prevent caching for relevant paths within the web root. Alternatively, most web development platforms allow you to control the server's caching directives from within individual scripts. Ideally, the web server should return the following HTTP headers in all responses containing sensitive content:
Cache-control: no-store
Pragma: no-cache
Request
GET /msg/keine+Session+mehr.htm HTTP/1.1 Host: maildomain.web.de Connection: keep-alive Referer: http://burp/show/16 Cache-Control: max-age=0 User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/534.16 (KHTML, like Gecko) Chrome/10.0.648.151 Safari/534.16 Accept: application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5 Accept-Encoding: gzip,deflate,sdch Accept-Language: en-US,en;q=0.8 Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3 Cookie: emos_webde_vid=AAABLtSLhHmpABw4zP5PeVODs7dkXu9_:2:AAABLtSNbCqzQSUHnTM4d48JcGoTXg3o:1300646161450:0:true:1; emos1und1d1_jcvid=AAABLtSSgBYgxv1GXnhi2VG16deIh1cG:1:AAABLtSSgBYgxv1GXnhi2VG16deIh1cG:1300646494230:0:false:10; NGCount=X0712311Ecvg017X; ns_sample=55
Response
HTTP/1.1 200 OK Date: Sun, 20 Mar 2011 19:49:34 GMT Server: Apache/2.0.63 (Unix) mod_ssl/2.0.63 OpenSSL/0.9.8h Cache-control: private,max-age=66820,pre-check=66820 Vary: Accept-Encoding Connection: close Content-Type: text/html; charset=iso-8859-1 Content-Length: 8571
The server presented a valid, trusted SSL certificate. This issue is purely informational.
The server presented the following certificates:
Server certificate
Issued to:
maildomain.web.de
Issued by:
Thawte SSL CA
Valid from:
Thu Jul 22 19:00:00 CDT 2010
Valid to:
Sun Aug 14 18:59:59 CDT 2011
Certificate chain #1
Issued to:
Thawte SSL CA
Issued by:
thawte Primary Root CA
Valid from:
Sun Feb 07 18:00:00 CST 2010
Valid to:
Fri Feb 07 17:59:59 CST 2020
Certificate chain #2
Issued to:
thawte Primary Root CA
Issued by:
Thawte Premium Server CA
Valid from:
Thu Nov 16 18:00:00 CST 2006
Valid to:
Wed Dec 30 17:59:59 CST 2020
Certificate chain #3
Issued to:
Thawte Premium Server CA
Issued by:
Thawte Premium Server CA
Valid from:
Wed Jul 31 19:00:00 CDT 1996
Valid to:
Fri Jan 01 17:59:59 CST 2021
Issue background
SSL helps to protect the confidentiality and integrity of information in transit between the browser and server, and to provide authentication of the server's identity. To serve this purpose, the server must present an SSL certificate which is valid for the server's hostname, is issued by a trusted authority and is valid for the current date. If any one of these requirements is not met, SSL connections to the server will not provide the full protection for which SSL is designed.
It should be noted that various attacks exist against SSL in general, and in the context of HTTPS web connections. It may be possible for a determined and suitably-positioned attacker to compromise SSL connections without user detection even when a valid SSL certificate is used.Report generated by XSS.CX at Sun Mar 20 15:02:44 CDT 2011.