CRLF Injections and HTTP Response Splitting

Hello, Khabrovites! In anticipation of the start of classes in the next group of the professional course "Web Application Security" , we have prepared for you another useful translation.

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What is CRLF?

-, , HTTP- , . HTTP- HTML- ( ) , (carriage return) (line feed). CRLF.

- CRLF, , HTTP- . CRLF - , . CRLF – HTTP/1.1, -, Apache, Microsoft IIS .

CRLF-?

CRLF- , , - , , , . , CRLF- , HTTP- (HTTP Response Splitting).

CRLF- -

- CRLF- , , . , -. CRLF- - , OWASP Top 10. , , .

CRLF-

IP — – , :

123.123.123.123 - 08:15 - /index.php?page=home

CRLF- HTTP-, . - - :

/index.php?page=home&%0d%0a127.0.0.1 - 08:15 - /index.php?page=home&restrictedaction=edit

%0d %0a – URL CR LF. , , , :

IP — –

123.123.123.123 - 08:15 - /index.php?page=home&
127.0.0.1 - 08:15 - /index.php?page=home&restrictedaction=edit

, CRLF-, , . hijacking . , , restrictedaction, .

, , IP restrictedaction, , - . , localhost (, , , -, , , ), .

, %0d%0a . & restrictedaction, , . , , :

/index.php?page=home&restrictedaction=edit

HTTP Response Splitting

HTTP- CRLF, . CRLFCRLF , . , HTML-. .

HTTP Response Splitting, XSS

, , :

X-Your-Name: Bob

GET- «name». URL- , CRLFCRLF, . , , XSS:

?name=Bob%0d%0a%0d%0a<script>alert(document.domain)</script>

.

HTTP-

CRLF-, HTTP-, , XSS- (same-origin-policy). , CSRF-. cookie, (XSS).

HTTP-

HTTP-, CORS (Cross Origin Resource Sharing), javascript , SOP (Same Origin Policy), .

CRLF-

CRLF- XSS . , XSS Same Origin Policy , .

CRLF/HTTP- -

– . , CRLF. – , CR LF , HTTP-.

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