Security firm Kaspersky has confirmed that the malware supposedly being auctioned by the previously unknown Shadow Brokers group is almost certainly among tools used by the US National Security Agency-linked Equation Group.
Kaspersky was the first security company to identify the Equation Group and some of its tools in a report published in 2015. It conjectured that Equation Group, which had a 15-year history of highly targeted attacks against nation states, was a front for the NSA.
The security firm claimed that a rare implementation of RC5/RC6 symmetric encryption-key block ciphers is one of a number of factors linking the Shadow Brokers dump with the Equation Group malware.
"Along with some non-native rants against ‘Wealthy Elites', the Shadow Brokers provided links to two PGP-encrypted archives. The first was provided for free as a presumptive show of good faith, the second remains encrypted at the time of writing," said Kaspersky's Global Research & Analysis Team in a blog post.
The pass-phrase is supposedly being ‘auctioned', but with a reserve price of one million bitcoins, more than $570m at the current price.
Initial tests of the released archive of malware indicate that the exploits do work.
"The first archive contains close to 300MB of firewall exploits, tools and scripts under cryptonyms like BANANAUSURPER, BLATSTING and BUZZDIRECTION. Most files are at least three years old, with change entries pointing to August 2013 as the newest timestamp dating to October 2013," said the team.
"While we cannot surmise the attacker's identity or motivation nor where or how this pilfered trove came to be, we can state that several hundred tools from the leak share a strong connection with our previous findings from the Equation Group."
The basis for the claims are the use of RC5 and RC6 symmetric encryption-key block ciphers, which will have been used to protect the malware when stored on a server ‘in the field' rather than on a server directly controlled by the NSA, assuming that the NSA was ultimately responsible for devising the malware.
"The Shadow Brokers' free trove includes 347 different instances of RC5/RC6 implementations. Comparing the older, known Equation RC6 code and the code used in most of the binaries from the new leak we observe that they are functionally identical and share rare specific traits in their implementation," said Kaspersky.
So rare is the RC6 implementation in particular, that it has been seen before only in Equation Group malware.
"There are more than 300 files in the Shadow Brokers' archive which implement this specific variation of RC6 in 24 different forms. The chances of all these being faked or engineered is highly unlikely," said the post.
"This code similarity makes us believe with a high degree of confidence that the tools from the Shadow Brokers leak are related to the malware from the Equation Group."
The evidence may go some way to firming up NSA whistleblower Edward Snowden's conjecture that the auction is intended as a coded message from Russian intelligence to the US.
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