Tracked through issue 65 (http://code.google.com/p/naxsi/issues/detail?id=65), fixed at check-in R545 (http://code.google.com/p/naxsi/source/detail?spec=svn545&r=545).
On Mon, Mar 25, 2013 at 10:00 PM, <saf...@gmail.com> wrote: > OWASP WAF Naxsi bypass Vulnerability > > Certain unspecified input is not properly handed in > naxsi_src/naxsi_utils.c naxsi_unescape_uri(u_char **dst, u_char **src, > size_t size, ngx_uint_t type) before being used to filtered. This can > be exploited to bypass some WAF rules. > > Naxsi site > https://code.google.com/p/naxsi/ > > Affected > All the version > > My site > http://safe3.com.cn/ > > My nick name is Safe3 > > It happens like that,the naxsi_unescape_uri function process the % url > decode,if the next char after the % is a hex char and not after the > hex char,then it will drop the % and the next char.So if we input a > sql keyword "s%elect",it will come to "slect" instead,this is not the > standard url decode way.Such as the IIS asp,it will process the > "s%elect" as a result of "select",so we can bypass some > WAF rules just like that. > > I afford a standard url decode function patch as the follow to fix this issue: > ...
