Re: Strange SMTP sessions with 'helo=<large negative number>' syntax
Michel Arboi <[email protected]>
| Newsgroups | gmane.comp.security.incidents |
|---|---|
| Message-ID | <[email protected]> |
On 28/12/05, max <[email protected]> wrote: > to=<[email protected]> proto=SMTP helo=<-1217882552> > Notice that helo section is a negative number (which is why my postfix rejects the message) Spammers sometimes hide IP addresses (in URL) by using a 32 bits integer. And also that they often use buggy tools.<grin> Maybe they tried to use this trick in the HELO command? -1217882552+2^32 = 3077084744 = 183.104.150.72 -1218008120+2^32 = 3076959176 = 183.102.171.200 Both addresses seems to be unassigned, my hypothesis looks wrong :-( > Has anyone noticed this as well? I don't have this in my logs.