Telstra BigPond users have been among those targeted. BigPond customers who install insecure mail server software -- which is configured by default to allow spammers to relay their messages -- has been used as a foot-hold for spammers to get on to the BigPond network. Once they've taken over the user's machine they can access the BigPond mail servers, just as Telstra's own customers can.
A spokesperson for Telstra said its servers are appealing to spammers because U.S.-based ISPs such as AOL are configured to always allow mail from BigPond servers.
"Spammers who find broadband vulnerabilities can utilise the BigPond relays in certain instances... and take advantage of BigPond white-listing agreements," the spokesperson told ZDNet Australia.
The technique is nothing new, according to SpamTrap's operations manager Michael Herman. Spammers would rather configure vulnerable mail servers that are configured to act as open-relays to send messages through BigPond's mail servers -- the practice makes it virtually impossible for ISP's receiving the spam to simply drop all messages originating from the telco's mail systems.
"There's less motivation to block Telstra's mail servers because it will hurt their customers more," Herman said.
By mixing their spam with as much legitimate traffic as they can, it makes it harder for the recipients to filter the good from the bad -- if the spammer simply uses the vulnerable open-relay as a one-stop spam relay, then network operators can just blacklist that machine's IP address and the spam will be rejected, he said.
BigPond isn't the only Australian ISP to be targeted. "Has it happened at other ISP's? Definitely," Herman added.
In response to these types of spamming techniques, Telstra scans its customers for vulnerable open-relay configurations. If it finds one, it contacts the customer and instructs them on tightening up their security.
"Proactive checking and shutting down of open-relay and BigPond customers who a using the system fraudulently ensures we remain off the blacklisting sites," the spokesperson said.
Telstra has found itself on the wrong side of an AOL list before. In April this year the company's mail servers were black-listed by the U.S. giant. Telstra at the time believed the action wasn't deliberate but the result of a mistake on the part of AOL.
T(H)elstra would have to be the worlds worst ISP.
1. It cannot tell the truth when things go wrong.
2. It allows open relay servers to blow us out of the water with SPAM.
3. It blames others all the time, for it's own incompetance.
4. It's servers are always being Black Listed, not just by AOL.
5. It does nothing to block deliquent users who don't have a fire wall or anti virus protection.
6. Users on T(H)elstra Broadband IntraNet are among the worlds worst at not keeping their PC's safe. The SPAM & Hacking on the IntraNet is huge.
7. It is the greediest ISP in the world.
8. It's broadband billing system is the worst in the world and it is NOT compatable with the rest of the T(H)elstra system.
9. It's Web site is the messiest in the world. What should only take 1-2 minutes to find, takes >30 minutes if you ever find the information you want at all.
10. Tech support is useless because none of the Engineering departments ever have to face the music (customers) so Tech support never gets the real story from Engineering and therfor never knows what is happening within it's network.
11. Tech support never has enough staff on duty to handle the huge load caused by never ending problems with all T(H)elstra data services.
12. Tech Support recorded messages are useless, because they are always out of date or misleading.
13. Tech Support NEVER believes they have a problem. All the savy user now ignore them when told to unload & rebuild their PC software and Network configuration files. If it were not so serious, it would be a huge joke.
14.Nothing has changed since the monopoly was disbanded (To the tune of) And the beat goes on & on & on & on