Sophisticated Trojan loots business bank accounts

German-speaking hacker crew hitting banks in US, UK, Spain and Italy

A German-speaking hacker crew is looting commercial bank accounts in four countries using a custom-built Trojan put in place by expertly crafted and extremely focused phishing attacks, a security researcher said Thursday.

The malware's most distinguishing feature, said Don Jackson, a senior security researcher at SecureWorks, is its ability to mimic the steps the human account owner would take to move money.

A variant of the Prg Banking malware, the new Trojan has stolen hundreds of thousands from accounts at some of the biggest banks in the US, the UK, Spain and Italy, said Jackson. "This is not widespread, but it is very dangerous. They've already stolen more than US$200,000 from the accounts we've monitored, but this has really flown under the radar."

Jackson also said he has found at least four servers that contain Prg configuration files and bogus versions of legitimate banking sites, as well as caches of data harvested by the Trojan.

The cleverness and technical know-how of the attackers was almost breathtaking. "If you were on the bank side of this connection [with the Trojan], it would appear to be a person on the other end running the account," Jackson said. "It would seem as if someone was clicking the keys on the virtual keyboard and sending wire transfers."

According to Jackson, the hackers -- who speak German, though they may not reside in Germany proper -- mined the vast amount of data collected previously by a less powerful generic version of Prg for evidence of commercial banking accounts, including specific URLs of offshore banks or indications of wire transfers.

The crew targeted commercial accounts, said Jackson, both because those accounts typically contain bigger balances and because they usually have the built-in ability to conduct wire transfers. Once they break into a business account, the hackers can quickly plunder it by using wire transfers to move its monies to hacker-controlled accounts.

With victim accounts picked, the hackers then create what Jackson called "very convincing" phishing e-mails and send them to the account owners, who have been identified using data stolen earlier. "They'll usually have the bank account number, and the first and last name of its owner," said Jackson, as well as security details, such as whether the account is protected by a one-time password. "The e-mail will claim that the user needs to download a new one-time password or soft token, but when the user clicks on the link and reaches the phish site, the Prg Trojan is downloaded instead."

From there, the highly automated account thief takes over. The malware alerts the hacker when the account owner is actually online with his bank, "piggybacking" on the session to silently steal the username and password without actually duping the user into entering it. Then using its ability to simulate keystrokes, the Trojan walks through all the steps a human being would take to, for instance, wire funds to another account. An account can be emptied in seconds.

"That's a very clever part of the Trojan," said Jackson. "How it downloads JavaScript from the command-and-control server so it looks like the [account owner] is accessing the account, not a bot." While less-sophisticated malware heads straight to a money transfer page without first appearing to "visit" the pages a real person would view before reaching the transfer page, Prg visits the bank's pages in order, as a person would. Because most antifraud looks for automated, nonhuman behavior, Prg won't trigger a fraud alert.

Each bank site has had customized code written for it, Jackson added, to make updating the Trojan-controlled PCs easier. If the hackers need to change the destination account -- because it's been spotted and frozen by local law enforcement, say -- a new one can be fed to the Trojans from the server.

"Fewer than 20 banks have been hit by this so far," said Jackson, "but they include some of the biggest banks in the US, UK, Spain and Italy.

He came close to praising the criminals. "To me, the automation of this is very, very crafty."

The surest defense against the Prg Trojan, Jackson concluded, is to be suspicious of any e-mail received from a bank. "Even if you recognize the sender, you should confirm that the sender sent that message before clicking on any links."

Join the newsletter!

Or

Sign up to gain exclusive access to email subscriptions, event invitations, competitions, giveaways, and much more.

Membership is free, and your security and privacy remain protected. View our privacy policy before signing up.

Error: Please check your email address.
Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.
Gregg Keizer

Gregg Keizer

Computerworld
Show Comments

Cool Tech

Bang and Olufsen Beosound Stage - Dolby Atmos Soundbar

Learn more >

Toys for Boys

ASUS ROG, ACRONYM partner for Special Edition Zephyrus G14

Learn more >

Sony WF-1000XM3 Wireless Noise Cancelling Headphones

Learn more >

Nakamichi Delta 100 3-Way Hi Fi Speaker System

Learn more >

Family Friendly

Mario Kart Live: Home Circuit for Nintendo Switch

Learn more >

Philips Sonicare Diamond Clean 9000 Toothbrush

Learn more >

Stocking Stuffer

Teac 7 inch Swivel Screen Portable DVD Player

Learn more >

SunnyBunny Snowflakes 20 LED Solar Powered Fairy String

Learn more >

Christmas Gift Guide

Click for more ›

Brand Post

Most Popular Reviews

Latest Articles

Resources

PCW Evaluation Team

Tom Pope

Dynabook Portégé X30L-G

Ultimately this laptop has achieved everything I would hope for in a laptop for work, while fitting that into a form factor and weight that is remarkable.

Tom Sellers

MSI P65

This smart laptop was enjoyable to use and great to work on – creating content was super simple.

Lolita Wang

MSI GT76

It really doesn’t get more “gaming laptop” than this.

Jack Jeffries

MSI GS75

As the Maserati or BMW of laptops, it would fit perfectly in the hands of a professional needing firepower under the hood, sophistication and class on the surface, and gaming prowess (sports mode if you will) in between.

Taylor Carr

MSI PS63

The MSI PS63 is an amazing laptop and I would definitely consider buying one in the future.

Christopher Low

Brother RJ-4230B

This small mobile printer is exactly what I need for invoicing and other jobs such as sending fellow tradesman details or step-by-step instructions that I can easily print off from my phone or the Web.

Featured Content

Product Launch Showcase

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?