Modifying SQL Queries Before Execution

We have the following case: an application modifies a table in an Oracle db (10.2.0.3.0).

Unfortunately the update SQL statements from the application always use the condition "where Column1 = 'some given value'" which is wrong (never mind why).

It should be instead "where Column1 = 'some value' and Column2 = 'val for Column2'. The 'val for Column2 will be taken from the very SQL query being issued (we can make the application do an update for Column2 even if the value in it never changes).

So all the update queries from the application look at the moment like that:

"update my_table set Column2 = 'val for Column2', Column3 = 'some other values', Column4 = 'some other value' where Column1 = 'some given value'".

We would like to capture them and somehow on the fly modify them to look like that:

"update my_table set Column2 = 'val for Column2', Column3 = 'some other values', Column4 = 'some other value' where Column1 = 'some given value' and Column2 = 'val for Column2'".

Can a trigger "before update" do it? For some reason we cannot at the moment ask the vendor to change the hard code of the application so we are looking for a temporary workaround.