Bugtraq mailing list archives
SMTP server account probing
From: brett () LARIAT ORG (Brett Glass)
Date: Mon, 8 Mar 1999 12:13:22 -0700
Several ISPs throughout the Net are reporting an attack described at http://www.l8r.com/nwa/nwa1.htm In this attack, an SMTP server is probed for common names, presumably so that spam can the be targeted at them. The attacking machine connects and issues hundreds of RCPT TO: commands, searching a long list of common user names (e.g. susan) for ones that don't cause errors. It then compiles a list of target addresses to spam. Unfortunately, the attack -- besides allowing the perpetrator to spam users -- also brings SMTP servers to their knees. This happens most often if the server maintains lists of user names in a database where looking up a name requires substantial disk activity or computational overhead. Some people whose domain names have been hard-coded into a commercial program designed to implement this attack have responded with outrage, e.g. http://www.junk.org/earthonline/ I'm surprised that I haven't seen this one on the Bugtraq list yet. --Brett Glass
Current thread:
- SMTP server account probing Brett Glass (Mar 08)
- Re: SMTP server account probing Frank Miller (Mar 09)
- Re: SMTP server account probing John E. Martin (Mar 09)
- Re: SMTP server account probing Brett Glass (Mar 09)
- Re: SMTP server account probing Nick Andrew (Mar 09)
- Re: SMTP server account probing Brian Behlendorf (Mar 09)
- Re: SMTP server account probing Valdis.Kletnieks () VT EDU (Mar 09)
- Re: SMTP server account probing Scott Fendley (Mar 09)
- Re: SMTP server account probing Alexander Bochmann (Mar 10)
- Re: SMTP server account probing Alan Cox (Mar 09)
- Re: SMTP server account probing Brett Glass (Mar 09)
- Re: SMTP server account probing Ryan Permeh (Mar 09)