Security experts are claiming to have uncovered a huge online banking botnet of 500,000 compromised computers which may already have stolen credentials for 800,000 transactions from some of the biggest US banks.
Proofpoint claimed in a new report, Analysis of a Cybercrime Infrastructure, that the attackers used admin credentials bought on the black market to access WordPress accounts and upload malware to legitimate looking sites as well as distributing infected newsletter content.
Said compromised sites contain a link to a Traffic Distribution System (TDS) which will ensure the incoming browser is a legitimate target, and that URLs won’t be blocked by anti-virus. It will then exploit a browser vulnerability to insert a 'dropper' – in this case, Qbot – to download additional malware.
Qbot also connects back to C&C severs to give the attacker visibility into what they have compromsied
The report continued:
“Proofpoint has seen that these systems are not only effective, but flexible: because of the use of an emplaced ‘dropper’ rather than a single piece of malware, the compromised computer can be stocked with multiple elements of malware, assisting the malware in avoiding signature detection (if one element is detected, others may not be) as well as in ensuring the compromised system can be used in multiple way.”
Wayne Huang, vice president of engineering at Proofpoint, told Infosecurity that the Russian cyber-criminals behind the campaign have “been spreading this qbot for more than a year" and a "purely financially" motivated.
He highlighted the use of SocksFabric as a particularly interesting element of the attacks.
Aside from merely using Qbot to steal banking credentials, the malware includes another module – SocksFabric – which builds up a tunneling network that lets attackers build their own ‘private cloud’ to run encrypted communications and transfer stolen data, or “use the compromised end points as infiltration points into targeted organizations.”
This service can be rented to other attackers in order to offer another source of revenue for the attackers.
Thus far, 500,000 systems have been compromised thanks to WorldPress, stealing online credentials for up to 800,000 bank accounts which could generate millions, not counting the extra revenue from the SocksFabric service.