How to Implement Best Cyber Defense Against BlackMatter Ransomware Attacks

How to Implement Best Cyber Defense Against BlackMatter Ransomware Attacks

Three U.S. government agencies, the Cybersecurity, and Infrastructure Security Agency (CISA), the Federal Bureau of Investigation (FBI), and the National Security Agency (NSA), recently issued a cyber security alert and defense tips against BlackMatter ransomware attacks.

What Is BlackMatter Ransomware?

BlackMatter is a relatively new ransomware. It was first observed in the wild in July 2021. This new ransomware exhibits the typical features of a modern-day ransomware, including the double extortion modus operandi.

In double extortion, the ransomware group steals data from victims. After stealing data, the attackers then encrypt victims’ data, preventing victims from accessing their data. After data encryption, attackers demand from victims ransom payment in exchange for a decryption tool that purportedly would unlock the encrypted data.

In double extortion, failure on the part of the victims to pay the ransom payment for the decryption tool leads to the activation of the second ransom demand, that is, victims are named on a leak site as victims of ransomware attacks. These victims are then threatened that their data will be published in case they won’t pay ransom.

Some ransomware actors still demand the second ransom payment – for the non-publication of the stolen data – despite the payment of the first ransom payment, that is, payment for the decryption tool.

Like other modern-day ransomware, BlackMatter ransomware is operated under the scheme called ransomware-as-service (RaaS). In RaaS, the ransomware developer (the one who creates the ransomware custom exploit code) works with affiliates – a different kind of cyberattackers who have existing access to corporate networks.

In a public advertisement posted on the underground forum Exploit, BlackMatter said it wants to buy access to corporate networks in the U.S., Canada, Australia, and Great Britain.

The group further said that it’s willing to pay $3,000 to $100,000 per network, provided the network passed the following criteria:

• Corporate revenue is $100 million or more
• Corporate network contains 500-15,000 devices
• Network hasn’t been previously targeted by other threat actors.

To signify that it's serious about its offer, BlackMatter has deposited 4 bitcoins ($256,000) on the forum Exploit.

“The [BlackMatter] ransomware is provided for several different operating systems versions and architectures and is deliverable in a variety of formats, including a Windows variant with SafeMode support (EXE / Reflective DLL / PowerShell) and a Linux variant with NAS support: Synology, OpenMediaVault, FreeNAS (TrueNAS). According to BlackMatter, the Windows ransomware variant was successfully tested on Windows Server 2003+ x86/x64 and Windows 7+ x64 / x86,” Recorded Future reported. “The Linux ransomware variant was successfully tested on ESXI 5+, Ubuntu, Debian, and CentOs. Supported file systems for Linux include VMFS, VFFS, NFS, VSAN.”

On BlackMatter website, the group said it doesn't attack hospitals, critical infrastructure, oil and gas industry, defense industry, non-profit companies, and government sector.

According to the joint cybersecurity advisory by CISA, FBI, and NSA, since July 2021, BlackMatter ransomware has targeted multiple U.S. critical infrastructure entities, including two food and agriculture sector organizations in the U.S., and have demanded ransom payments ranging from $80,000 to $15,000,000 in cryptocurrencies Bitcoin and Monero.

In September 2021, BlackMatter attacked the U.S. farmers cooperative NEW Cooperative and demanded from the victim $5.9 million for the decryptor and for the non-publication of the stolen data. 

"Your website says you do not attack critical infrastructure,” a NEW Cooperative representative told BlackMatter during a negotiation chat (screenshots of the said negotiation chat were shared online). “We are critical infrastructure... intertwined with the food supply chain in the US. If we are not able to recover very shortly, there is going to be very very public disruption to the grain, pork, and chicken supply chain."

BlackMatter Ransomware Tactics, Techniques, and Procedures

The CISA, FBI, and NSA advisory said that sample of BlackMatter ransomware analyzed in a sandbox environment as well from trusted third-party reporting showed that BlackMatter ransomware uses the following tactics, techniques, and procedures:

• BlackMatter harvests credentials from Local Security Authority Subsystem Service (LSASS) memory using procmon.
• BlackMatter uses Lightweight Directory Access Protocol (LDAP) and Server Message Block (SMB) protocol to discover all hosts in the Active Directory (AD).
• BlackMatter uses NtQuerySystemInformation to enumerate running processes.
• BlackMatter uses EnumServicesStatusExW to enumerate running services on the network.
• BlackMatter uses srvsvc.NetShareEnumAll MSRPC function to enumerate and SMB to connect to all discovered shares, including ADMIN$, C$, SYSVOL, and NETLOGON.
• BlackMatter uses legitimate remote monitoring and management software and remote desktop software, often by setting up trial accounts, to maintain persistence on victim networks.
• BlackMatter exfiltrates data.
• BlackMatter remotely encrypts shares via SMB protocol and drops a ransomware note in each directory.
• Rather than encrypting backup systems, BlackMatter wipes or reformats backup data stores and appliances.

Cybersecurity Best Practices

The CISA, FBI, and NSA advisory recommends the following cybersecurity defense tips against BlackMatter ransomware attacks:

• Use strong passwords for service account, admin accounts, and domain admin accounts.
• Use multi-factor authentication (MFA) for vital services, including webmail, virtual private networks (VPNs), and accounts that access critical systems.
• Keep all software up to date.
• Eliminate unnecessary access to administrative shares.
• Use a host-based firewall – a firewall installed on a server to monitor and control incoming and outgoing network traffic.
• Implement network segmentation to prevent the spread of ransomware.
• Disable command-line and scripting activities and permissions.
• Keep all backup data offline, encrypted, and immutable.
• Disable the storage of clear text passwords in LSASS memory.
• Disable or limit New Technology Local Area Network Manager (NTLM) and WDigest Authentication.