Repudiation Attack

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A repudiation attack happens when an application or system does not adopt controls to properly track and log users’ actions, thus permitting malicious manipulation or forging the identification of new actions. This attack can be used to change the authoring information of actions executed by a malicious user in order to log wrong data to log files. Its usage can be extended to general data manipulation in the name of others, in a similar manner as spoofing mail messages. If this attack takes place, the data stored on log files can be considered invalid or misleading.

Risk Factors



Consider a web application that makes access control and authorization based on JSESSIONID, but registers user actions based on a user parameter defined on the Cookie header, as follows:

POST http://someserver/Upload_file.jsp HTTP/1.1
Host: tequila:8443
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US; rv: Gecko/20070515 Firefox/
Accept: text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5
Accept-Language: en-us,en;q=0.5
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
Keep-Alive: 300
Connection: keep-alive
Referer: http://someserver/uploads.js
Cookie: JSESSIONID=EE3BD1E764CD6EED280426128201131C; user=leonardo
Content-Type: multipart/form-data; boundary=---------------------------263152394310685
Content-Length: 321

And the log file is composed by:

Date, Time, Source IP, Source port, Request, User

Once user information is acquired from user parameter on HTTP header, a malicious user could make use of a local proxy (eg:paros) and change it by a known or unknown username.


Category:OWASP ASDR Project Category:Resource Manipulation Category:Attack