To better hide card-skimming devices, fraudsters are using 3D printers to craft them to exact specifications.

Such printers emit powder that is heated and then hardened to create 3D sculptures based on computer instructions, and "word is spreading in the cybercrime underworld that 3D printers produce flawless skimmer devices with exacting precision," Brian Krebs reported Tuesday at krebsonsecurity.com.

One group allegedly used this technique to steal $400,000, he wrote.

Skimming devices are placed over card readers on ATMs and point of sale terminals to capture card data as it is swiped. And if the skimming devices "don't match just-so, they're more likely to be discovered and removed" before the thieves can access the stolen card data, Krebs wrote.

Four men were indicted in South Texas for allegedly using a 3D printer to make new skimming devices after their earlier supplier, a Houston resident named Jason Lall, was sent to prison for ATM fraud in 2009, Krebs wrote.