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Splunk spots malware targeting Windows Server on AWS to mine Monero

Data analysis firm Splunk says it’s found a resurgence of the Crypto botnet – malware that attacks virtual servers running Windows Server inside Amazon Web Services.

Splunk’s Threat Research Team (STRT) posted its analysis of the attack on Monday, suggesting it starts with a probe for Windows Server instances running on AWS, and seeks out those with remote desktop protocol (RDP) enabled.

Once target VMs are identified, the attackers wheel out an old favourite: brute forcing passwords. If that tactic succeeds, the attackers get to work and install cryptomining tools that produce the Monero cryptocurrency.

Secure messaging app Telegram plays a role, too. Attackers install it and use it to carry command and control messages.

Splunk’s security team noticed that one of the Monero wallets used in this campaign was also involved in a 2018 wave of attacks using the same Crypto botnet.

But this time around the attack differs in using resources identifiable as being from China and Iran. China seems the likely location of some malicious domains associated with the attack, and Iran is seen as the source of sites and Telegram channels that have left fingerprints in code and victim machines.

Splunk’s advice for those hoping to avoid the attack is simple: stay up to date with patches, use strong passwords, and enable network-level authentication. Windows admins will also know that RDP is not on by default, for good reasons – advice for those not wanting to avoid the attack is presumably to switch on RDP, use ‘Admin/Passw0rd1234’ as the login credentials and let ‘er rip.

The vendor has published a guide to the attack here. ®