The Anubis Backdoor: A Silent Threat Targeting Your Enterprise Through SharePoint

In the proactive cyber threat landscape, organizations must stay alert to advanced persistent threats (APTs) targeting their assets for espionage and direct financial gain. The latest development tied to the infamous threat actor FIN7 raises alarms across industries. On April 2, 2025, cybersecurity researchers uncovered the deployment of a Python-based backdoor dubbed Anubis, designed to hijack Windows systems through compromised Microsoft SharePoint environments. With a history of breaching major organizations and evading detection, FIN7’s revival poses significant financial, operational, and reputational risks to enterprises worldwide.

Anubis Backdoor

Anubis is more than just another backdoor—it’s modular and stealthy malware designed to operate directly in memory, making traditional detection methods ineffective. Distributed via malspam campaigns, victims are lured into opening ZIP archives that contain a Python script. This script decrypts and executes an obfuscated payload in memory, initiating a persistent command-and-control (C2) session with a remote server via Base64-encoded TCP traffic.

FIN7's Persistent Legacy in Cybercrime

FIN7, also known as Carbon Spider or Sangria Tempest, is a Russian-based financially motivated threat group with a long track record of conducting sophisticated cyberattacks. Initially known for targeting the retail, hospitality, and restaurant sectors, FIN7 has continuously evolved its tools, tactics, and procedures (TTPs). In recent years, they have transitioned into ransomware affiliate operations while maintaining their foothold in custom malware development and access-as-a-service operations.

In mid-2024, FIN7 was linked to promoting a tool called AuKill, which disables security tools before malware deployment. Their expertise in weaponizing trusted platforms such as SharePoint shows a deep understanding of enterprise ecosystems and how to exploit them.

Financial Fallout and High-Profile Breaches

FIN7's actions have historically led to catastrophic breaches with tangible financial consequences. One of the most notable incidents involved the compromise of more than 100 U.S. companies, resulting in the theft of over 15 million credit card records and estimated damages exceeding $1 billion. The group has also been linked to the 2017 breach of Chipotle (2,250 restaurants affected), where customer payment data was siphoned and sold on dark web marketplaces.

Compliance Failure: Financial Penalties

Anubis is engineered to stealthily bypass endpoint detection and response (EDR) solutions, particularly in enterprises that underfund cybersecurity or overlook the hardening of platforms like Microsoft SharePoint. A single successful compromise can result in catastrophic consequences: intellectual property theft, ransomware extortion, operational disruption, and regulatory penalties.

Organizations operating in regulated industries—such as healthcare, finance, and critical infrastructure—are particularly vulnerable. Under GDPR, for instance, data breaches involving personally identifiable information (PII) can trigger fines of up to €20 million or 4% of global annual turnover, whichever is higher. The Cyber Resilience Act (CRA) introduces liability for insecure-by-design software, giving regulators the authority to suspend products from the market or impose administrative fines reaching €15 million or 2.5% of the annual global turnover, whichever is higher.

Recommendations to Protect Your Enterprise

To counter threats like Anubis, organizations should implement a multi-layered defense strategy:

• Apply the principle of least privilege across all systems and accounts.

• Regularly patch operating systems, third-party applications, and cloud services.

• Update endpoint protection and perimeter security tools with the latest signatures.

• Monitor for anomalous SharePoint activity and outbound Base64-encoded TCP traffic.

• Educate employees on phishing risks and safe email practices.

• Back up data regularly and test recovery procedures.

• Implement robust intrusion detection and prevention systems (IDPS).

Additionally, compliance with GDPR, HIPPA, and the CRA must be continuously validated to monitor security and regulatory posture across the company.

How Cytopus Can Help Your Business?

Our automated security solutions and proactive threat management ensure your business remains secure and compliant in an ever-changing cyber landscape.

• Compliance & Regulatory Alignment: Cytopus helps organizations meet GDPR, DORA, CRA, and NIS2 security requirements, reducing the risk of compliance penalties, legal consequences, and reputational damage from ransomware-induced data breaches.

• Ransomware Prevention & Threat Intelligence: Our continuous monitoring and AI-driven threat intelligence detect ransomware activities before they escalate. By integrating with SIEM, EDR, and XDR solutions, Cytopus identifies and neutralizes malicious behaviors, preventing unauthorized encryption and data exfiltration.

• Zero Trust & Access Control Enforcement: We implement Zero Trust security policies, ensuring only authorized users and devices access sensitive systems. By restricting access to essential applications and services, Cytopus reduces attack surfaces exploited by threat actors.

• Incident Response & Forensics: In the event of an attack, Cytopus provides rapid response, forensic analysis, and automated containment strategies to mitigate damage, recover compromised systems, and prevent reoccurrence.

• Business Continuity & Disaster Recovery Planning: Our experts help organizations develop, test, and refine Disaster Recovery Plan (DRP) and Business Continuity Plan (BCP) strategies, ensuring resilience against ransomware incidents, supply chain compromises, and cyber extortion tactics.