If the update of the stats via web front-end is allowed,
a remote attacker can execute arbitrary code on the server
using a specially crafted request involving the migrate
parameter. Input starting with a pipe character ("|")
leads to an insecure call to Perl's open function and the
rest of the input being executed in a shell. The code is
run in the context of the process running the AWStats
CGI.
Arbitrary code can be executed by uploading a specially
crafted configuration file if an attacker can put a file
on the server with chosen file name and content (e.g. by
using an FTP account on a shared hosting server). In this
configuration file, the LogFile directive can be used to
execute shell code following a pipe character. As above,
an open call on unsanitized input is the source of this
vulnerability.