Section 1: Executive Summary: Profiling Arachna

A new threat actor, designated Arachna, was first observed in September 2025 and represents a significant evolution in data extortion tactics. The group is named for the master weaver of Greek myth, reflecting a patient and intricate operational methodology.

Arachna is a financially motivated organized crime entity specializing in data theft and extortion, deliberately forgoing the use of file-encrypting ransomware. Their current operational focus is on the global Retail and Wholesale sectors, targeting the valuable customer and financial data these industries possess.

The group’s modus operandi involves gaining initial access, moving laterally with stealth, and meticulously collecting sensitive data. This stolen information is then exfiltrated to a Tor-based leak site, where victims are publicly named and threatened with data release to compel payment.

Key artifacts include a ransom note named Restore-Files-Guide.txt, which is dropped on compromised systems despite the absence of encryption. The primary impacts on victims are severe data theft, subsequent financial losses, and significant reputational damage stemming from the public disclosure of sensitive information.

Defensive strategies must evolve to counter this threat, shifting focus from preventing file encryption to prioritizing the detection of anomalous data access, aggregation, and exfiltration. Organizations must assume that a breach can be silent and centered entirely on the theft of information, rendering traditional anti-ransomware controls insufficient.

Section 2: Origins and Motivation: The Weaver’s Web

Emergence and Naming

The Arachna group, also known by the variant “Arachne,” surfaced in the threat landscape in September 2025. Its name is a direct reference to the Greek mythological figure Arachne, a mortal woman whose weaving skills were so profound they challenged a goddess.

This choice of name is not arbitrary; it serves as a metaphor for the group’s operational philosophy. Like a spider patiently weaving a complex web, Arachna demonstrates a preference for methodical, intricate network infiltration over the disruptive, brute-force tactics of traditional ransomware. Their attacks are characterized by a “low-and-slow” approach, carefully gathering threads of data from disparate systems to construct a comprehensive and damaging trove of information.

Operational Classification

Based on their extortion-driven business model, Arachna is classified as a financially motivated organized crime group. Their objectives are purely monetary, distinguishing them from state-sponsored actors who typically pursue espionage, intellectual property theft for national gain, or disruptive geopolitical goals.

The selection of targets within the retail sector further solidifies this classification. The primary goal is to acquire data with a high market value for extortion, such as payment card information and personally identifiable information (PII), which can be immediately monetized or used as leverage.

Psychological and Financial Drivers

Arachna’s strategy is rooted in a sophisticated understanding of modern business risk. They have calculated that for many organizations, particularly in consumer-facing industries, the threat of reputational damage and regulatory fines is a more powerful motivator for payment than operational downtime.

By threatening to release sensitive customer data, they weaponize the trust between a company and its clientele. The potential for brand erosion, customer churn, and multi-million dollar fines under data privacy regulations like GDPR or CCPA creates immense pressure to pay the ransom, even if the victim’s systems remain fully operational and their data is securely backed up.

Section 3: Operational Doctrine: Extortion Without Encryption

The Exfiltration-Only Model

Arachna’s core doctrine is a significant departure from the dominant ransomware playbook. They have deliberately uncoupled the act of data theft from data encryption, focusing exclusively on the former to achieve their financial objectives.

This “extortion-without-encryption” model streamlines their operation and enhances their stealth. By forgoing the deployment of a file encryptor, they avoid the noisy, CPU-intensive processes that often trigger alerts from Endpoint Detection and Response (EDR) and antivirus solutions, allowing them to remain undetected for longer periods.

Leveraging Reputational and Regulatory Risk

This operational model fundamentally shifts the battlefield from data availability to data confidentiality. Arachna’s primary weapon is the threat of public exposure, which directly targets a victim’s brand reputation and legal standing.

For a retail company, the public release of millions of customer records, including names, addresses, and purchase histories, can be an extinction-level event. The group leverages this fear, knowing that the cost of the ransom may seem small compared to the potential long-term financial and reputational fallout from a public data leak.

Comparison to Traditional Ransomware Groups

When contrasted with legacy ransomware groups like Conti or LockBit, the advantages of Arachna’s approach become clear. They significantly reduce their development overhead by not needing to create, maintain, and update a complex and often-buggy encryption locker.

Most critically, this model renders a victim’s backup and recovery strategy completely irrelevant to the extortion demand. An organization can have a world-class, air-gapped backup system capable of restoring operations in minutes, but this provides no defense against the threat of having its sensitive data published online.

The Psychology of the Ransom Note

A key element of their methodology is the deployment of a ransom note named Restore-Files-Guide.txt. The name is intentionally misleading, as no files are encrypted or require restoration. This is a calculated psychological tactic designed to sow confusion during the initial stages of incident response.

Upon discovering this note, an incident response team’s first instinct is to follow the standard ransomware playbook: search for encrypted files, identify the scope of encryption, and initiate data recovery from backups. This misdirection wastes critical time and resources, diverting the defenders’ attention from the true nature of the attack. While the security team is hunting for a non-existent encryption event, they are not investigating the real damage—the scope and scale of the data exfiltration—giving Arachna a greater window to cover their tracks or prepare the stolen data for public release.

This choice of filename may also indicate the group’s technical origins. It is plausible that Arachna’s operators are using a modified version of a common ransomware-as-a-service (RaaS) toolkit, in which they have simply disabled the file encryption module. This is a critical clue for threat hunters, as it suggests that other indicators of compromise (IOCs) associated with a known “parent” ransomware family—such as specific registry keys, mutexes, or C2 communication patterns—might also be present in Arachna’s intrusions, providing valuable leads for detection and attribution.

Section 4: The Attack Lifecycle: A Detailed TTP Analysis (Aligned with MITRE ATT&CK®)

The following analysis provides a detailed, plausible reconstruction of Arachna’s attack chain, mapped to the MITRE ATT&CK® framework. This model is based on their observed targeting of the retail sector and their exfiltration-focused operational doctrine.

4.1 Initial Access (TA0001)

Arachna’s entry into a target network likely relies on exploiting the perimeter’s weakest points. This is often achieved through common, yet effective, techniques tailored to their target industry.

• T1190 – Exploit Public-Facing Application: The group is assessed to heavily favor the exploitation of unpatched vulnerabilities in internet-facing systems common to retail and e-commerce. This includes known CVEs in e-commerce platforms like Magento or PrestaShop, content management systems (CMS), and remote access infrastructure such as VPN concentrators or RDP gateways.
• T1566 – Phishing: Targeted spear-phishing campaigns remain a high-probability access vector. These campaigns would be carefully crafted to appeal to employees in corporate roles with access to valuable data, such as finance, HR, or marketing departments. Lures would be contextually relevant, masquerading as supplier invoices, shipping notifications, or customer complaints to entice a user to open a malicious attachment or click a credential-harvesting link.

4.2 Execution & Persistence (TA0002, TA0003)

Once inside, Arachna prioritizes stealth and maintaining long-term access. They achieve this by leveraging built-in system tools to blend in with normal administrative activity.

• T1059.001 – PowerShell / T1059.003 – Windows Command Shell: The group makes extensive use of “living-off-the-land” binaries (LOLBins). PowerShell and the Windows Command Shell are used to execute commands, download additional tools from actor-controlled infrastructure, and perform initial reconnaissance without writing new malicious binaries to disk, thereby evading simple signature-based detection.
• T1547.001 – Registry Run Keys / Startup Folder & T1053.005 – Scheduled Task: To ensure their access survives a system reboot, Arachna establishes persistence through common Windows mechanisms. They may create new registry keys under Run or RunOnce hives or create a scheduled task configured to launch their backdoor or C2 beacon at regular intervals, often disguised with a legitimate-sounding name like “SystemUpdate” or “AdobeUpdater.”

4.3 Privilege Escalation & Defense Evasion (TA0004, TA0005)

To gain full control of the network, the actor must escalate privileges and neutralize security controls. This phase is critical for enabling unrestricted lateral movement and data access.

• T1068 – Exploitation for Privilege Escalation: On internal systems that may not be as rigorously patched as the perimeter, Arachna likely uses known local privilege escalation exploits. Vulnerabilities like PrintNightmare (CVE-2021-34527) or ZeroLogon (CVE-2020-1472) could be used to escalate from a compromised standard user account to the all-powerful NT AUTHORITY\SYSTEM or Domain Admin level.
• T1562.001 – Disable or Modify Tools: With elevated privileges, a key objective is to operate unobserved. The group will actively attempt to terminate or disable security agents, such as EDR clients and antivirus software, by killing their processes or stopping their associated services, effectively blinding the security team to their subsequent actions.

4.4 Credential Access & Discovery (TA0006, TA0007)

With elevated rights and disabled defenses, Arachna begins the core intelligence-gathering phase of the operation. Their goal is to map the network and locate the most valuable data repositories.

• T1003 – OS Credential Dumping: The actor almost certainly uses credential dumping tools to harvest credentials from memory. A tool like Mimikatz would be deployed to target the Local Security Authority Subsystem Service (LSASS) process on key servers, extracting plaintext passwords, NTLM hashes, and Kerberos tickets that allow them to impersonate legitimate users and access other systems.
• T1087.002 – Domain Account Discovery: Using built-in tools like net user /domain, they enumerate all accounts within the Active Directory domain. This allows them to identify high-privilege service accounts, domain administrators, and the accounts of key personnel in finance or database administration.
• T1016 – System Network Configuration Discovery & T1049 – System Network Connections Discovery: To understand the network topology, they execute basic commands like ipconfig /all, netstat -an, and arp -a. This helps them identify subnet ranges, active network connections, and the locations of critical infrastructure like domain controllers and file servers.
• T1213 – Data from Information Repositories: This is the central objective of the discovery phase. The group actively scans the network for database servers (listening on ports like 1433 for MSSQL or 1521 for Oracle), open SMB file shares, and SharePoint sites. They search for file shares named “Finance,” “HR,” or “Customer Data,” and query databases for tables containing PII or payment card information.

4.5 Collection & Staging (TA0009)

Before exfiltration, the stolen data must be consolidated and prepared for extraction. This is done carefully to avoid triggering network data flow alerts.

• T1074 – Data Staged: Arachna creates a hidden staging directory on a compromised server, preferably one with high uptime but low user traffic to avoid discovery. Common locations include C:\ProgramData\Temp\, C:\Users\Public\Downloads\, or similarly innocuous-looking paths.
• T1560.001 – Archive via Utility: To manage the large volume of data and provide a layer of obfuscation, the group uses legitimate archiving utilities. They would use the command-line versions of 7-Zip or WinRAR to compress the collected files into a single or multiple password-protected archives (e.g., .zip, .rar, .7z). The data is often split into smaller, uniformly sized chunks to evade detection rules based on large file transfers.

4.6 Command and Control (C2) (TA0011)

Throughout the operation, Arachna maintains communication with compromised systems for command execution and tool delivery. Their C2 traffic is designed to be difficult to distinguish from legitimate network activity.

• T1071.001 – Web Protocols: