Hive Ransomware

It has been reported that Hive ransomware is employing a wide variety of tactics, techniques, and procedures (TTPs) to compromise business networks. Hive RaaS owners build personalized ransomware kit, customized for various operating systems.

Infection Mechanism

Hive affiliates resort to various initial compromise methods, such as vulnerable RDP servers, compromised VPN credentials, as well as phishing emails with malicious attachments. Hive generally uses applications like Cobalt Strike, ConnectWise, ADrecon during the attack. Hive ransomware attempts to dump credentials, cache clear text credential data and use tools like ADrecon to “map, traverse, and enumerate” the Active Directory (AD) environment. It seeks processes related to backups, anti-virus/anti-spyware, and file copying and terminates them to facilitate file encryption. The encrypted files commonly end with a .hive extension. The Hive ransomware then drops a hive.bat script into the directory, which enforces an execution timeout delay of one second in order to perform cleanup after the encryption is finished by deleting the Hive executable and the hive.bat script. A second file, shadow.bat, is dropped into the directory to delete shadow copies, including disc backup copies or snapshots, without notifying the victim and then deletes the shadow.bat file. During the encryption process, encrypted files are renamed with the double final extension of *.key.hive or *.key.*.

The ransom note, “HOW_TO_DECRYPT.txt” is dropped into each affected directory and states the *key.* file cannot be modified, renamed, or deleted, otherwise the encrypted files cannot be recovered. The note contains a “sales department” link, accessible through a TOR browser, enabling victims to contact the actors through a live chat. The ransom note also contains URL of the public disclosure / leak site, which is accessible on a TOR browser.

Fig.1 Ransom note by Hive Ransomware

Indicator of Compromise:

Winlo.exe

• MD5: b5045d802394f4560280a7404af69263
• SHA256: 321d0c4f1bbb44c53cd02186107a18b7a44c840a9a5f0a78bdac06868136b72c
• File Path Observed C:\Windows\SysWOW64\winlo.exe
• Drops 7zG.exe

7zG.exe

• MD5: 04FB3AE7F05C8BC333125972BA907398
• This is a legitimate 7zip, version 19.0.0
• Drops Winlo_dump_64_SCY.exe

Winlo_dump_64_SCY.exe

• MD5: BEE9BA70F36FF250B31A6FDF7FA8AFEB
• Encrypts files with *.key.* extension
• Drops HOW_TO_DECRYPT.txt

Other IOCs:

• *.key.hive
• *.key.*
• HOW_TO_DECRYPT.txt
• hive.bat
• shadow.bat
• vssadmin.exe delete shadows /all /quiet
• wmic.exe SHADOWCOPY /nointeractive
• wmic.exe shadowcopy delete
• wevtutil.exe cl system
• wevtutil.exe cl security
• wevtutil.exe cl application
• bcdedit.exe /set {default} bootstatuspolicy ignoreallfailures
• bcdedit.exe /set {default} recoveryenabled no

Anonymous File Sharing Links:

• hxxps://anonfiles[.]com
• hxxps://mega[.]nz
• hxxps://send[.]exploit[.]in
• hxxps://ufile[.]io
• hxxps://www[.]sendspace[.]com

Best Practices and Recommendations:

• Maintain offline backups of data, and regularly maintain backup and restoration. This practice will ensure the organization will not be severely interrupted, have irretrievable data.
• Ensure all backup data is encrypted, immutable (i.e., cannot be altered or deleted) and covers the entire organization’s data infrastructure
• Implement all accounts with password logins (e.g., service account, admin accounts, and domain admin accounts) to have strong, unique passwords.
• Implement multi-factor authentication for all services to the extent possible, particularly for webmail, virtual private networks, and accounts that access critical systems.
• Remove unnecessary access to administrative shares
• Use a host-based firewall to only allow connections to administrative shares via server message block (SMB) from a limited set of administrator machines
• Enable protected files in the Windows Operating System to prevent unauthorized changes to critical files
• Disable remote Desktop Connections, employ least-privileged accounts. Limit users who can log in using Remote Desktop, set an account lockout policy. Ensure proper RDP logging and configuration
• Check regularly for the integrity of the information stored in the databases
• Ensure integrity of the codes /scripts being used in database, authentication and sensitive system
• Establish Domain-based Message Authentication, Reporting, and Conformance (DMARC), Domain Keys Identified Mail (DKIM) and Sender Policy Framework (SPF) for your domain, which is an email validation system designed to prevent spam by detecting email spoofing by which most of the ransomware samples successfully reaches the corporate email boxes.
• Keep the operating system third party applications (MS office, browsers, browser Plugins) up-to-date with the latest patches
• Application white listing/Strict implementation of Software Restriction Policies (SRP)to block binaries running from %APPDATA% and %TEMP% paths. Ransomware sample drops and executes generally from these locations.
• Maintain updated Antivirus software on all systems
• Don't open attachments in unsolicited e-mails, even if they come from people in your contact list, and never click on a URL contained in an unsolicited e-mail, even if the link seems benign. In cases of genuine URLs close out the e-mail and go to the organization's website directly through browser
• Follow safe practices when browsing the web. Ensure the web browsers are secured enough with appropriate content controls.
• Network segmentation and segregation into security zones - help protect sensitive information and critical services. Separate administrative network from business processes with physical controls and Virtual Local Area Networks.
• Disable ActiveX content in Microsoft Office applications such as Word, Excel, etc.
• Restrict access using firewalls and allow only to selected remote endpoints, VPN may also be used with dedicated pool for RDP access
• Use strong authentication protocol, such as Network Level Authentication (NLA) in Windows.
• Additional Security measures that may be considered are
• Use RDP Gateways for better management
• Change the listening port for Remote Desktop
• Tunnel Remote Desktop connections through IPSec or SSH
• Two-factor authentication may also be considered for highly critical systems
• If not required consider disabling, PowerShell / windows script hosting.
• Restrict users' abilities (permissions) to install and run unwanted software applications.
• Enable personal firewalls on workstations.
• Implement strict External Device (USB drive) usage policy.
• Employ data-at-rest and data-in-transit encryption.
• Consider installing Enhanced Mitigation Experience Toolkit, or similar host-level anti-exploitation tools.
• Block the attachments of file types, exe|pif|tmp|url|vb|vbe|scr|reg|cer|pst|cmd|com|bat|dll|dat|hlp|hta|js|wsf
• Carry out vulnerability Assessment and Penetration Testing (VAPT) and information security audit of critical networks/systems, especially database servers from CERT-IN empanelled auditors. Repeat audits at regular intervals.
• Individuals or organizations are not encouraged to pay the ransom, as this does not guarantee files will be released. Report such instances of fraud to CERT-In and Law Enforcement agencies

References:

• https://www.cisa.gov/uscert/ncas/current-activity/2021/08/27/fbi-releases-indicators-compromise-associated-hive-ransomware
• https://blog.group-ib.com/hive