Exclusive Cybaze ZLab – Yoroi – Hunting Cozy Bear, new campaign, old habits

The experts at Cybaze ZLab – Yoroi continue the analysis of new strain of malware used by the Russia-linked APT29 cyberespionage group (aka Cozy Bear)

The experts at Cybaze ZLab – Yoroi continue the analysis of new strain of malware used by the Russia-linked APT29 cyberespionage group (aka The Dukes, Cozy Bear, and Cozy Duke).

The researchers of Yoroi ZLab, on 16 November, accessed to a new APT29’s dangerous malware which seems to be involved in the recent wave of attacks aimed at many important US entities, such as military agencies, law enforcement, defense contractors, media companies and pharmaceutical companies.

Threat actors carried out spear phishing attacks impersonating a State Department official to attempt compromising targets

The experts discovered that Cozy Bear cyberspies used in the last campaign a technique to drop malicious code that was already employed by threat actors.

APT29 along with APT28 cyber espionage group was involved in the Democratic National Committee hack and the wave of attacks aimed at the 2016 US Presidential Elections.

The same technique has been used by the APT group back in 2016 when the Cozy Bear in the aftermath of the US Presidential Election.

At the time, Cozy Bear hackers carried out spear-phishing attack using a zip file containing a weaponized self-extracting link file that drops a decoy document and the final payload.

The researchers at Cybaze ZLab – Yoroi pointed out that the technique used to avoid detection is very sophisticated.

“The usage of a link file containing the complete payload is a powerful technique, still hard to detect by several common anti-virus solutions. Despite the effectiveness of this strategy, the creation of the weaponized LINK such the one analyzed is quite easy,  many publicly available resources could help crooks to abuse it.” reads the analysis published by Cybaze ZLab – Yoroi researchers.

The C2C “pandorasong[.]com” recalls the legit “pandora.com” domain name, one of the most popular music streaming service in the US. Moreover, the requests sent by the malware are forged to look like as legit Pandora traffic, using information publicly available on GitHub.

According to FireEye’s report the final DLL contains a beaconing payload generated with Cobalt Strike, a well-known post-exploitation framework typically used by Red-Teams.

The complete analysis conducted by Cybaze ZLab – Yoroi, including the Yara rules, are reported in a blog post on the Yoroi blog.

https://blog.yoroi.company/research/new-cozy-bear-campaign-old-habits/

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Pierluigi Paganini

(Security Affairs – Cozy Bear APT, cyberespionage)

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