Bugtraq: Re: sendmail 8.9.3 patches to curb RCPT harvesters

[achurch () DRAGONFIRE NET (Andy Church)]

> > Per Joseph's suggestion. Use these patches against sendmail 8.9.3 and add
> >
> > O RCPTFailDelay=30
> >
> > to sendmail.cf to make sendmail sleep() for 30 seconds before reporting any
> > "550" errors. Set the value to 0 for "normal"  behavior.
> According to the reports I'm seeing, GeoList Pro does not wait for a
> response from the server -- instead, it streams the RCPT TO commands
> continuously and then reads the results at the end of transmission.
> If that is the case, it doesn't sound like this patch will have any
> effect.
     It should work fine, because (1) sendmail won't process anything while
it's sleep()ing, and (2) GeoList will stop sending data when the socket
buffer fills up (because sendmail isn't reading from it).

  --Andy Church
    achurch () dragonfire net
    http://achurch.dragonfire.net/