A new report has revealed that Iranian government agents or supporters are changing entries in Wikipedia to downplay the regime’s crimes and discredit dissidents.
In some circumstances, pages may need to be protected from modification by certain groups of editors. Pages are protected when a specific damaging event has been identified that cannot be prevented through other means such as a block.
https://en.wikipedia.org/wiki/Wikipedia:Protection_policy
edit: also https://en.wikipedia.org/wiki/Vandalism_on_Wikipedia