TOTVS RM Portal Login.aspx cross site scripting

A vulnerability classified as problematic has been found in TOTVS RM 12.1. Affected is an unknown function of the file Login.aspx of the component Portal. The manipulation of the argument VIEWSTATE leads to cross site scripting. It is possible to launch the attack remotely. The complexity of an attack is rather high. The exploitability is told to be difficult. It is possible to mitigate the problem by applying the configuration setting <pages validateRequest="true" [...] viewStateEncryptionMode="Always" />. It is recommended to change the configuration settings. The vendor was initially contacted early about this disclosure but did not respond in any way. In a later statement he explains, that "the behavior described [...] is related to specific configurations that are not part of the default application setup. In standard production environments, the relevant feature (VIEWSTATE) is disabled by default, which effectively mitigates the risk of exploitation."