New Database Botnet Leveraged for Bitcoin Mining

An organized group of cybercriminals is currently targeting database services in a new botnet build-up that's being leveraged for cryptocurrency mining, among other more traditional botnet attack patterns.

Discovered by researchers with GuardiCore Labs, the so-called Hex-Men attacks have been slowly evolving since March and remain ongoing. 

The researchers say there are three main variants - Hex, Hanako, and Tayler - each of which target different SQL servers and have their own unique goals, scale, and target servers. Based on the evidence they've gathered, it appears the attackers are based out of China, with a heavy emphasis on Chinese victims but also plenty of other targets located in Thailand, the US, Japan, and other targets globally.

All three variants are difficult to detect as every machine attacking database servers only targets a few IPs at a time. Victim machines are used as a part of the botnet, but rotated out of use within about a month.

The truly unique part of this attack, says Daniel Goldberg, researcher with GuardiCore and a co-author of the report, is the sensitivity of the machines being targeted. These are production Web servers, MS SQL Servers, ElasticSearch management nodes, MySql services, and so on.

Possibly tens of thousands of servers have been compromised at this point, he says, with all of them being used in the rotation to help build a botnet that's "very different" from the ones you typically hear about these days, which primarily target low-profile IoT devices and sensors.

"In a way it's back to old times of attacking strong, powerful servers and abusing their power," he says. "Every single one of these compromised servers is holding real data. It could be, tomorrow the attackers could decide they want to encrypt all this data, turn it into a ransomware attack. They could steal all of it, they could publish it. But what they're doing right now is using the servers for cryptocurrency mining, and they're using the servers to make their botnet bigger."

The attack can be particularly problematic to block in a complex enterprise environment due to the low-level nature of the attack pattern and the difficulty large organizations have in not only controlling, but even having visibility into, which databases are Internet-facing. 

Today, where everything is in the cloud and you have multiple environments and different data centers, it’s really hard to keep track on what is exposed and what is not," says Ofri Ziv, vice president of research for GuardiCore and co-author of the report today.

"The fact that they are targeting databases is pretty amazing to me and it's something that people need to really, really pay more attention to," he says.

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