A hacking group has installed crypto mining malware into a company server through a weakness in Salt, a popular infrastructure tool used by the likes of IBM, LinkedIn and eBay.

Blogging platform Ghost said Sunday an attacker had successfully infiltrated its Salt-based server infrastructure and deployed a crypto-mining virus.

"Our investigation indicates that a critical vulnerability in our server management infrastructure ... was used in an attempt to mine cryptocurrency on our servers," reads an incident report. "The mining attempt spiked CPUs and quickly overloaded most of our systems, which alerted us to the issue immediately."

Ghost said Monday developers had removed the mining malware from its servers and added whole new firewall configurations.

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Salt is an open-source framework, developed by SaltStack, that manages and automates key parts of company servers. Clients, including IBM Cloud, LinkedIn, and eBay, use Salt to configure servers, relay messages from the "master server" and issue commands to a specific time schedule.

SaltStack alerted clients a few weeks ago there was a "critical vulnerability" in the latest version of Salt that allowed a "remote user to access some methods without authentication" and gave "arbitrary directory access to authenticated users."

SaltStack also released a software update fixing the flaw on April 23.

Android mobile operating system LineageOS said hackers had also accessed its core infrastructure via the same flaw, but the breach was quickly detected. In a report Sunday the company admitted it hadn't updated the Salt software.

It remains unknown whether the same group is behind the LineageOS and Ghost attacks. Some attacks have planted crypto mining software, while others have instead planted backdoors into servers.

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It isn't clear if hackers mined a particular cryptocurrency. Hacking groups have generally favored monero (XMR), as it can be mined with just general purpose CPUs, not dedicated mining chips, and can be traded with little risk of detection.

CoinDesk has approached SaltStack for comment, but hadn't heard back by press time.