Added code to skip suspicious looking query variables
On openacs.org, we are experiencing numerous requests with multiply very long and strange query variables like in the example below. So far, it is not clear, whether these requests are the consequence of a double encoding or a deliberate attack. Many (most) of the requests contain the query variable names containing the (decoded) pattern "*amp;*".
This is a relatively new phenomenon. I cannot exclude that this is a bug introduced lately in OpenACS, or a bug in an external bot, or whatever. The problem with these query variables is that OpenACS propagates these further, e.g., when updating query variables in ad_dimensional, via export_vars, or return_urls.
Since OpenACS never uses these query-variables, these can be safely skipped, without loosing functionality in OpenACS. It is possible to construct examples, where skipping such variables can change the semantics. Therefore, the change introduces a single function util::suspicious_query_variable where in case of problems, the skipping feature can be deactivated.
GET /api-doc/proc-browse?amp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3btype=All&amp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3borderby=name&type=All&amp%3btype=All&amp%3bamp%3btype=All&amp%3bamp%3bamp%3btype=All&amp%3bamp%3bamp%3bamp%3btype=All&amp%3bamp%3bamp%3bamp%3bamp%3btype=All&amp%3bamp%3bamp%3bamp%3bamp%3bamp%3btype=All&amp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3btype=All&amp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3btype=All&amp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3borderby=name&amp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3btype=Private&amp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3btype=All&amp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3btype=All&amp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3btype=All&amp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3borderby=name&amp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3bamp%3btype=All HTTP/1.1" 200 62378 "" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/605.1.15 (KHTML, like Gecko; compatible; FriendlyCrawler/1.0) Chrome/120.0.6099.216 Safari/605.1.15" "1729029614.331581 0.109805 0.000434 0.004026 0.215927