The Shadow Brokers are back again after their summer hiatus, advertising new leaks. The hacker group posted a new message, promising to deliver two data dumps a month as part of its monthly dumps of alleged stolen NSA exploits.

The hacker group made headlines after publicly leaking NSA exploits in April, some of which were later used to launch the massive global WannaCry and NotPetya ransomware attacks. The mysterious hacker group is now only accepting payments in ZCash and has also raised the rates for exploits, demanding nearly $4m (£3m).

The amount marks a substantial increase, when compared to the group's initial demand of 100 ZEC, when the hackers started their first monthly dump in June. Now, the hackers are demanding 16,000 ZEC, which amounts to $3,914,080.

According to security researcher Rickey Gevers, the founder of the non-profit organisation, the GDI Foundation, the hackers leaked the manual for an NSA exploit dubbed UNITEDRAKE, which according to the leaked manual, is a "fully extensible remote collection system designed for Windows targets".

According to documents previously leaked by Edward Snowden, the UNITEDRAKE implant was designed to be used by the NSA's elite hacking unit TAO (Tailored Access Operations).

According to a 2011 report by Kaspersky, UNITEDRAKE, which they identified as EquationDrug, was the "main espionage platform" of the NSA's Equation Group hacker unit.

Although the Shadow Brokers are believed to have raked in an estimated $90,000 from their monthly dumps, some security experts have cast doubts on whether the group is financially motivated.

Although it still remains unclear as to how the Shadow Brokers managed to obtain the NSA's cyberweapons, US authorities investigating the leaks are reportedly looking into former insiders who may have links to the hacker group. Authorities suspect that a former disgruntled NSA agent or an insider within the US intelligence community may have been involved in the theft and leak of the NSA hacking tools. However, the latest message indicates that the Shadow Brokers continue to evade the authorities.