Grief Ransomware Group

Phishing: Targeted spear-phishing emails containing malicious attachments or links are a common entry vector. These emails might lead to the download of encoded text files or other loaders that execute initial commands.

Exploiting Vulnerabilities: Leveraging unpatched vulnerabilities in public-facing applications or systems.

RDP Compromise: Brute-forcing or using stolen credentials to gain access via Remote Desktop Protocol (RDP). Understanding brute force attacks is essential for securing RDP.

Precursor Malware: Grief intrusions are frequently observed in environments already compromised by the Dridex banking trojan. Dridex often serves as the initial access vector, establishing a foothold.

Dridex Activity: Dridex often uses DLL Search Order Hijacking (T1574.001), relocating legitimate system binaries (like msinfo32.exe, dialer.exe) to non-standard paths (e.g., %APPDATA%) and loading malicious DLLs masquerading as legitimate ones (e.g., mfc42u.dll, version.dll).

Cobalt Strike Deployment: Following a Dridex infection, attackers often deploy Cobalt Strike beacons for enhanced command and control, lateral movement, and privilege escalation. Cobalt Strike frequently uses Process Injection (T1055) into legitimate processes like svchost.exe, often resulting in these processes running without command-line arguments.

Grief Execution: The Grief ransomware payload itself is often executed via rundll32.exe loading a malicious DLL (using DllRegisterServer).

Persistence Mechanisms:

Operators use tools like Cobalt Strike and native Windows utilities (LOLBins) to escalate privileges. Understanding privilege escalation attacks is key to preventing them.

Extensive use of takeown.exe and icacls.exe to take ownership and modify permissions on files and directories, particularly targeting backup-related files to hinder recovery.

Lateral movement is achieved using RDP, SMB protocols, and tools deployed via Cobalt Strike.

Safe Mode Boot: Forcing the system into Safe Mode hinders security software and simplifies encryption.

LOLBins: Using native Windows tools (rundll32.exe, bcdedit.exe, takeown.exe, icacls.exe, powershell.exe, Windows Command Shell) makes malicious activity harder to distinguish from legitimate administration.

Disabling Security Tools: Attempts to modify Windows Defender settings via registry changes.

Code Obfuscation: Internal strings within the malware are encrypted using RSA-2048, AES-256, and RC4.

Backup Deletion: While some analyses didn't observe automatic shadow copy deletion by the ransomware binary itself, operators typically perform this manually using vssadmin or other tools before deploying the final payload. They also target backup files directly using takeown/icacls.

Data Theft: Significant volumes of sensitive data are exfiltrated before encryption, often using legitimate cloud storage services or C2 channels via encrypted HTTPS.

Encryption: Employs a strong combination of RSA-2048 and AES-256 algorithms to encrypt victim files. Encrypted files are typically appended with a specific extension.

Ransom Note & Leak Site: A ransom note (!!!READ_ME!!!.txt) is dropped, directing victims to a Tor-based portal (nearly identical to DoppelPaymer's) for payment instructions and negotiation. The site features a "shaming" list where victim data is leaked if the ransom isn't paid. Grief demands payment in Monero (XMR).

Pressure Tactics: Grief operators have threatened to delete decryption keys if victims engage third-party negotiation firms and leverage GDPR references on their leak site to increase pressure. They may also engage in phishing to further compromise victims.

Data Breach: Exfiltration of sensitive corporate, customer, or employee data, leading to regulatory fines (e.g., GDPR), legal action, and reputational damage. Data breaches can have long-lasting consequences.

Operational Disruption: Encryption of critical systems can halt business operations for extended periods, causing significant revenue loss and recovery costs.

Financial Loss: Costs include ransom payments (if made), incident response, system restoration, legal fees, and potential regulatory penalties.

Healthcare

Financial Services

Government (including municipalities)

Education (including school districts)

Manufacturing

Technology

Entertainment

National Rifle Association (NRA) Attack (October-November 2021): This high-profile incident demonstrated Grief's capabilities and willingness to target prominent organizations. Around October 27, 2021, Grief listed the NRA on its leak site, initially releasing a small subset of documents (meeting minutes, grant applications). After briefly removing the listing (potentially during negotiations or due to unwanted attention), Grief released a larger trove of sensitive data around November 10, allegedly including employee PII like bank details and Social Security numbers. The NRA remained largely silent, neither confirming the breach nor stating if a ransom was paid, drawing criticism. The attack highlighted the complexities involved, including the need for Treasury Department approval if the NRA had chosen to pay, due to Grief's suspected link to the sanctioned Evil Corp.

Attack on Thessaloniki, Greece (Late 2021): Grief targeted the municipality of Thessaloniki, the second-largest city in Greece, causing significant disruption to public services. This attack underscored the group's willingness to impact governmental entities.

Attack on German Government District (Late 2021): Reports indicated Grief successfully targeted a major government district in Germany, further demonstrating their focus on high-value public sector targets.

Multiple Manufacturing and Service Companies: Throughout its operation, Grief has listed numerous victims from the manufacturing, technology, and professional services sectors on its leak site, showcasing its broad reach across various industries. Recent reports have indicated that supply chain attacks are becoming increasingly common.

Security Awareness Training: Educate employees to recognize and report phishing attempts, suspicious attachments, and links. Companies are implementing phishing simulations to better train employees.

Email Security: Implement robust email filtering solutions to block malicious emails, attachments, and URLs.

Patch Management: Maintain a rigorous patch management program to address vulnerabilities in operating systems, applications (especially public-facing ones), and firmware promptly. A comprehensive patch management strategy is essential for mitigating risks.

Access Control: Enforce the principle of least privilege. Use strong, unique passwords for all accounts and mandate Multi-Factor Authentication (MFA), especially for remote access (RDP, VPN) and privileged accounts.

RDP Hardening: Secure RDP access by using strong passwords, MFA, Network Level Authentication (NLA), limiting access via firewalls, and using VPNs. Disable RDP if not required.

Network Segmentation: Segment networks to limit the blast radius if an infection occurs, preventing easy lateral movement.

Disable Unused Services: Reduce the attack surface by disabling unnecessary protocols and services.

Endpoint Detection and Response (EDR/XDR): Deploy advanced EDR/XDR solutions capable of behavioral analysis to detect suspicious activities associated with Grief's TTPs, such as:

Network Monitoring: Monitor network traffic for unusual patterns, C2 communications (Cobalt Strike beacons often have specific patterns), large data exfiltration attempts, and connections to known malicious IPs or domains.

Log Management & SIEM: Collect and analyze logs from endpoints, servers, and network devices. Use a SIEM to correlate events and alert on suspicious sequences indicative of Grief activity (e.g., Dridex indicators followed by Cobalt Strike, then file permission changes). Understanding security logging and monitoring can improve detection capabilities.

Regular Audits: Conduct regular security audits and vulnerability assessments to identify and remediate weaknesses. A strong vulnerability assessment strategy is key.

Incident Response Plan: Develop and regularly test a comprehensive incident response plan. It is important to know why you need a CIRP and how to implement it.

Backup and Disaster Recovery (BDR): Implement a robust BDR strategy:

Isolation: Quickly isolate infected systems from the network to prevent further spread.

Ransom Payment Considerations: Avoid paying the ransom if possible. Payment fuels the ransomware ecosystem, does not guarantee data recovery or prevent data leaks, and may involve legal risks (especially with sanctioned groups like Evil Corp). Consult legal counsel and law enforcement.