Crooks appear to be taking advantage of the recent sale of the UK Ministry of Defence’s IPv4 address space to run more convincing scams.

They have purportedly bought blocks of IP addresses with previously pristine records to distribute scams. This malfeasance was enabled, in part, because the relevant Whois database entries were not updated. The issue surfaced via a thread on Reddit.

The fraudsters appear to be attempting to boost the credibility of scams and perhaps get past web filters, at least temporarily, by using a previously trusted and clean IP range to pump out invoice scams.

They are then asking people to pay invoices into accounts under their control, apparently maintained at a pre-paid cash-card firm.

Advanced Payment Solutions (APS) told El Reg that it was investigating the apparent abuse of its payment facilities.

“As an FCA-regulated institution, APS follows the same robust compliance procedures as a high street bank, when carrying out due diligence on every individual or business customer,” Rich Wagner, chief exec of Advanced Payment Solutions, said in a statement. “We take any claims of fraud extremely seriously, and will conduct a thorough investigation of the accounts in question.”

An expert in spam and phishing quizzed by El Reg noted that hackers had previously re-routed legitimate IP addresses using BGP (Border Gateway Protocol), then used those addresses to conduct their nefarious activities before releasing them again. "It may not be quite the same thing, but definitely sounds like a means of bypassing block-lists," the expert told us.

Tests using an IP address-looking tool suggest the IP address at issue is still allocated to the Ministry of Defence, at Woodstock in Oxfordshire.

The Redditor who reported the problem is adamant that the address isn’t faked and that “it shows in the Exchange tracking logs".

El Reg raised the issue to the MoD via its official Twitter profile (@DefenceHQ) but is yet to receive a reply.

Fake invoice scams are a growing problem in the UK and prompted a warning in August 2015 from Action Fraud for firms to be on their guard.

Botnote

Motivations for crooks to obtain second-hand IP addresses with a good reputation could range from boosting their credibility to minimising the chances of the IP being blocked on a blacklist, so that they can send spam, host phishing, or even command and control servers. ®