Pierluigi Paganini February 01, 2018

Researchers from security firm CrowdStrike spotted a new Monero crypto-mining worm dubbed WannaMine that spreads leveraging the NSA-linked EternalBlue exploit.

This morning I wrote about the Smominru botnet that used NSA exploit to infect more than 526,000 systems, and I explained that other threat actors are using similar techniques to mine cryptocurrency.

This is the case of a strain of the Monero crypto-mining worm dubbed WannaMine that spreads leveraging the EternalBlue exploit.

ETERNALBLUE is the alleged NSA exploit that made the headlines with DOUBLEPULSAR in the WannaCry attack, it targets the SMBv1 protocol and has become widely adopted in the community of malware developers.

In June, following the WannaCry attacks experts discovered that there were at least other 3 different groups have been leveraging the NSA EternalBlue exploit,

Back to the present, WannaMine was developed to mine the Monero cryptocurrency abusing victims’ resources. According to security researchers at CrowdStrike, the malicious code is very sophisticated, it implements a spreading mechanism and persistence model similar to those used by state-sponsored APT groups.

“CrowdStrike has recently seen several cases where mining has impacted business operations, rendering some companies unable to operate for days and weeks at a time. The tools have caused systems and applications to crash due to such high CPU utilization speeds.” reads the analysis published by CrowdStrike. 

“CrowdStrike has observed more sophisticated capabilities built into a cryptomining worm dubbed WannaMine. This tool leverages persistence mechanisms and propagation techniques similar to those used by nation-state actors, demonstrating a trend highlighted in the recent CrowdStrike Cyber Intrusion Services Casebook 2017, which states that “contemporary attacks continue to blur the lines between nation-state and eCrime tactics.”

WannaMine is a fileless that was first reported by researchers at Panda Security.

The malicious code implements so-called “living off the land” techniques to gain persistence on the infected system leveraging Windows Management Instrumentation (WMI) permanent event subscriptions. WannaMine registers a permanent event subscription that would execute every 90 minutes a PowerShell command located in the Event Consumer.

Experts noticed that the malware uses credential harvester Mimikatz to collect users’ credentials that could be used for lateral movements. It also relies on the EternalBlue exploit in case it is not able to move laterally with the above technique.

WannaMine is able to infect systems running all Windows versions starting with Windows 2000, including 64-bit versions and Windows Server 2003.

“While the tactics, techniques, and procedures (TTPs) displayed in WannaMine did not require a high degree of sophistication, the attack clearly stands on the shoulders of more innovative and enterprising nation-state and eCrime threat actors. CrowdStrike anticipates that these threat actors will continue to evolve their capabilities to go undetected,” CrowdStrike concluded.

WannaMine would degrade the performance of the infected machines, in case of laptops the malicious code could cause damages if it runs continuously for several hours.

Sophos experts published an interesting post containing Q&A on WannaMine.

Pierluigi Paganini

(Security Affairs – WannaMine , cryptocurrency miner)

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