SpamCannibal blacklist service reanimated by squatters, claims every IP address is spammy

Yes, even yours

Updated SpamCannibal – a defunct service that issued blacklists of known spam servers – was hijacked early on Wednesday morning, spewing its own unwanted crap in the process.

El Reg was tipped off by a reader who told us that SpamCannibal is "pumping out Blacklist notifications for some of our servers and then when you go to spamcannibal.org, you get spam." Visiting the site earlier today flung fake Adobe Flash updates at our sandboxed browser, downloads no doubt riddled with malware, so beware.

The site's blacklisting service has been inactive since last summer. The website's DNS name server settings were changed overnight, though, to deleterious effect, security researchers confirmed.

In short: someone changed SpamCannibal.org's DNS so it pointed at a system controlled by miscreants, so that they could lob dodgy stuff at unsuspecting netizens. And requests to check an IP address to see if it is blacklisted as a spam outlet always returned the same result: true.

If anybody uses spamcannibal's RBL, the domain has been taken over and has a wildcard response - so it returns everything as status spam. https://t.co/wBuzpWLjDR

— Kevin Beaumont 🐈 (@GossiTheDog) May 30, 2018

"A lookup for 1.2.3.4 on the blacklist would require a DNS lookup of 4.3.2.1.bl.spamcannibal.org. When a blacklist is active, a response (usually something like 127.0.0.1) means blacklisted, no record (NXDOMAIN) means not blacklisted," Martijn Grooten, editor of industry journal Virus Bulletin and sometime security researcher, told El Reg.

"In this case, the new 'owners' of the domain have set a wildcard domain, so that any subdomain of spamcannibal.org returns an IP address. This is interpreted as the domain being blacklisted."

Grooten, who cut his teeth testing the effectiveness of anti-spam products, suspected that the attack wasn't targeted.

"This really looks like a standard domain takeover by some dodgy parking service. Doesn't appear particularly targeted to Spamcannibal," he concluded. ®

Updated at 0701 on 5.06/18 to add: Spamhaus told The Reg after SpamCannibal returned to its dormant state: "[There] was no nefarious domain hijacking. The operator just decided to stop doing anti-spam efforts a year ago.

"Then when it was time to renew the domain last week, he decided not to. When it went into "renewal mode" at the registrar, that's when the DNS started returning a value for every query. Although its usage worldwide was relatively small, it was still enough to cause people issues. When in renewal, the domain is pointed to a parking page, normally displaying adverts.

"We at Spamhaus managed to quickly get the domain out of the 'renewal mode' at the registrar which temporarily stopped problem. We then tracked down the operator. Going forward, we've taken over the domain and operation. We'll wind it down over a long period following the proper DNS-blocklist RFC shutdown procedures."