With Bitcoin, and cryptocurrencies in general, growing in popularity, many customers have asked Cato Research Labs about Bitcoin security risks posed to their networks.
Cato Research Labs examined crypto mining and the threats posed to the enterprise. While immediate disruption of the network or loss of data is unlikely to be a direct outcome of crypto mining, increased facility costs may result. Indirectly, the presence of crypto mining software likely indicates a device infection.
Customers of Cato’s IPS as a service are protected against the threats posed by crypto mining. Non-Cato customers should block crypto mining on their networks. This can be done by disrupting the process of joining and communicating with the crypto mining pool either by blocking the underlying communication protocol or by blocking crypto mining pool addresses and domains. For a list of addresses and domains, you should block, click here.
The Risk of Crypto Mining and What You Can Do
Crypto mining is the validating of bitcoin (or other cryptocurrency) transactions and the adding of encrypted blocks to the blockchain. Miners establish valid block by solving a hash, receiving a reward for their efforts. The possibility of compensation is what attracts miners, but it’s the need for compute capacity to solve the hash that leads miners to leverage enterprise resources.
Mining software poses direct and indirect risks to an organization:
- Direct: Mining software is compute intensive, which will impact the performance of an employee’s device. Running processors at a “high-load” for a long time will increase electricity costs. The life of a processor or the battery within a laptop may be shortened.
- Indirect: Some botnets are distributing native mining software, which accesses the underlying operating system in a way similar to how malware exploits a victim’s device. The presence of native mining software may well indicate a compromised device.
Cato Research Labs recommends blocking crypto mining. Preferably, this should be done using the deep packet inspection (DPI) engine in your firewalls. Configure a rule to detect and the block the JSON-RPC messages used by Stratum, the protocol mining pools use to distribute tasks among member computers. DPI rules should be configured to block based on three fields which are required in Stratum subscription requests: id, method, and params.
However, DPI engines may lack the capacity to inspect all encrypted traffic. Blocking browser-based, mining software may be a problem as Stratum often runs over HTTPS. Instead, organizations should block access to the IP addresses and domains used by public blockchain pools.
Despite our best efforts, no such list of pool address or domains could be found, which led Cato Research Labs to develop its own blacklist. Today, the list identifies hundreds of pool addresses. The list can be download here for import into your firewall.
Cryptocurrency mining may not be the gravest threat to enterprise security, but it should not be ignored. The risk of impaired devices, increased costs, and infections means removing mining software warrant immediate attention. The blacklist of addresses provided by Cato Research Labs will block access to existing public blockchain pools, but not new pools or addresses. It’s why Cato Research strongly recommends configuring DPI rules on DPI engine that have sufficient capacity to inspect all encrypted sessions.