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PYSA: 2020 to Now

Arete Analysis

Cybersecurity Trends

Cyber Threats

PYSA is the newest variant of the Mespinoza Ransomware as a Service (RaaS) family, which was first observed infecting victims in the wild in December 2019. PYSA is likely a reference to the open-source web application auditing tool PYSA (Protect Your System Amigo) released by security engineers at Facebook.

Like Ryuk, PYSA is dubbed a “big game hunter” for their tendency to target large corporations. Based on their advanced encryption methods, double extortion tactics, and desire to distinguish themselves, this up-and-coming ransomware group is “one to watch.”

Since Q3 2020, Arete has responded to 26 total PYSA cases. With an average ransom payment of $346,603, PYSA ranks third highest in average ransom payouts tracked by Arete through July 2021. Additionally, Arete has observed a steady increase in cases sine Q3 2020 (see Figure 1).

Figure 1: PYSA cases over a one-year period.


Figure 2: Arete PYSA cases average ransom payment.

Targeting Big Game 

PYSA targets large companies or organizations susceptible to extortion, where business downtime would pose a significant impact to operations. By extorting companies with the threat of publishing sensitive data, PYSA increases the chances of ransom payments. The top three sectors targeted by PYSA include K-12 school systems (36%), professional services (20%), and healthcare providers (12%). See Figure 3 for all targeted sectors.

Figure 3: Arete PYSA cases, all targeted sectors.

Sophisticated Criminals 

PYSA exhibits discipline by first surveying compromised systems to determine a victim’s potential “extortion value.” Open-source reporting indicates that PYSA searches not only for common keywords (e.g., PII, balance, routing), but also for keywords (e.g., illegal, fraud, criminal) that could be evidence of illegal activities by the victim.

Arete also identified some other key PYSA activity — specifically, that PYSA occasionally publishes data on leak sites after payment, provides decryptors that partially corrupt data, and stops communication for multiple days during negotiations.

Figure 4: Average time of business interruption.

Infection vector and persistence: Human-operated ransomware

Arete identified the following PYSA tactics, techniques, and procedures (TTPs) as being consistent with manually operated ransomware during the initial access phase:

  • Uses brute force remote desktop protocol (RDP) attacks against central management consoles, domain controllers, and Active Directory accounts.

  • Exfiltrates password databases prior to exploitation.

  • Leverages Mimikatz in victim environments, likely to gain access to credentials.

Additionally, Arete observed the following persistence toolset as part of PYSA campaigns:

  • Gasket. A backdoor written in the Go programming language, Gasket is designed as a backup to RDP to maintain access to the network. Gasket has many capabilities (e.g., “MagicSocks”) that allow PYSA to tunnel traffic to an externally controlled server.

Figure 5: Gasket functionality.

  • MagicSocks. Leverages code from the Chisel project to tunnel traffic from the local system to an external, actor-controlled server. Next, uses Chisel code to tunnel traffic out of the local system to a landing page (“creatordampfe[.]xyz”) before routing the traffic to an unknown actor-controlled server.

Advanced encryption techniques

According to open-source data, PYSA uses Crypto++ to encrypt victim files with both RSA-4096 and AES-256-CFB. The group appends the encrypted files with the “.pysa” extension and leverages an allowlist and denylist to determine which files to encrypt.

  • The denylist contains all files to be encrypted.

  • The allowlist includes vital directories, such as Windows and Boot, which, if encrypted, would make recovery via the decryptor impossible. After, PYSA drops the ransom note (Figure 6) in every directory listed in the denylist.

Figure 6: PYSA ransom note.

PYSA threat likely to remain steady 

PYSA utilized the rapid shift of corporations to remote work during COVID-19 for opportunistic targeting against RDP and remote admin infrastructure. Arete asserts that the threat posed by PYSA campaigns will likely remain steady, with PYSA targeting larger corporations across sectors to demand higher ransom payments. PYSA’s discipline, target selection, and advanced encryption techniques make them a credible threat on the ransomware scene.

How Arete can help you “Protect Your Systems Amigo”

Arete has a complete suite of managed security services, including managed detection and response (MDR), SentinelOne Endpoint Detection and Response (EDR) software deployment, and Arsinal threat hunting services for defending against ransomware attacks.

The following rulesets would detect PYSA activity on a client endpoint:

  • PowerShell used to disable Windows Defender Protection.

  • Lsass dump.

  • Firewall Exception for Remote Desktop.

  • MS Windows Defender stopped.

  • Security Tool Services stopped.

  • Volume Shadow Copy deletion.

  • Process Masquerading in Registry – Svchost.

  • Advanced Port Scanner Tool download.

  • Advanced Port Scanner Process Masquerading.

  • Advanced Port Scanner Process.

  • Advanced Port Scanner File detected.

  • Mimikatz Process Execution.

  • Advanced IP Scanner Network Mapping Tool download.

  • Advanced IP Scanner Network Mapping Tool Process.

  • Advanced IP Scanner Network Mapping File detected.

  • Advanced IP Scanner Process Masquerading.

Indicators

Ransom Note Emails

  • johnfitzgerald@onionmail.org

  • cristianpalmerss@protonmail.com

  • wcraijones@protonmail.com

  • dec_restore1@outlook.com

  • zljanczplaizr@onionmail.org

  • EfreTavernia@protonmail.com

  • lizawilkinson@onionmail.org

  • Makailahuff@protonmail.com

  • Davionfinley@protonmail.com

  • joedansereau@onionmail.org

  • m0arc7bdhsohar@onionmail.org

  • david_ansty@protonmail.com

  • t.trstram@protonmail.com

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Current: Misconfigured Server Reveals Multiple Phishing Campaigns

Researchers uncovered three Microsoft 365 phishing campaigns after discovering a misconfigured HTTP server that exposed a threat actor’s phishing tools, configurations, victim logs, and operational infrastructure. The investigation revealed two operators using custom Evilginx-based adversary-in-the-middle (AiTM) phishing frameworks to steal authentication sessions and bypass MFA protections. A third operator abused Microsoft’s OAuth Device Code flow by tricking victims into completing authentication through Microsoft’s legitimate login process, allowing attackers to obtain valid access and refresh tokens without stealing passwords. The largest campaign compromised at least 218 victims across 12 countries, primarily targeting corporate Microsoft 365 accounts, with refresh tokens enabling persistent access. Researchers also identified the use of remote management tools for maintaining access, AI-assisted development of phishing tooling, and links to broader Phishing-as-a-Service (PhaaS) ecosystems, highlighting how commodity frameworks and automation are lowering the barrier for sophisticated identity-based attacks.

What’s Notable and Unique

  • The campaigns demonstrate the continued shift from traditional credential theft to identity- and token-based compromise, in which attackers target authentication sessions, cookies, and OAuth tokens rather than relying solely on password theft. By obtaining valid authentication artifacts, attackers can access Microsoft 365 environments while bypassing conventional MFA protections.


  • The use of Evilginx-based AiTM frameworks highlights how publicly available phishing tools have evolved into effective MFA-bypass platforms. These frameworks proxy legitimate login pages, capture authenticated sessions, and allow attackers to reuse valid sessions without requiring victims’ credentials again.


  • The OAuth Device Code flow abuse represents a different attack method, in which attackers leverage a legitimate Microsoft authentication mechanism to obtain tokens after victims approve the request. This approach bypasses password theft entirely by abusing trusted authentication workflows.


  • The exposed infrastructure provided insight into attacker operations, including phishing configurations, victim tracking data, remote administration tools, and evidence of AI-assisted development. The findings demonstrate how phishing ecosystems now provide reusable tooling and automation that reduce the technical expertise required to conduct large-scale identity attacks.

Analyst Comments

These Microsoft 365 phishing campaigns demonstrate the ongoing evolution of identity-focused attacks, as adversaries increasingly target authentication sessions, tokens, and legitimate cloud authorization mechanisms to bypass traditional security controls. The combination of AiTM phishing, OAuth abuse, remote management tools, and PhaaS infrastructure enables threat actors to maintain persistent access while blending into legitimate cloud activity.

The growing availability of phishing frameworks and AI-assisted attack development highlights the need for continuous identity security improvements beyond traditional phishing defenses. Arete recommends that organizations strengthen identity monitoring, adopt phishing-resistant MFA where possible, review OAuth application permissions, monitor token activity, and implement conditional access policies to detect and restrict suspicious Microsoft 365 authentication behavior. Security teams should also monitor post-compromise indicators such as abnormal mailbox access, suspicious application consent, unauthorized remote tools, and unusual sign-in activity.

Sources

  • One Misconfigured Server, Three Active Campaigns: Full exposure of three AiTM Phishing Operators

  • Misconfigured Server Reveals Three Evilginx Phishing Operations Targeting Microsoft 365

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Helix Extortion Group Debuts in SharePoint Data Theft Attacks

A newly identified data-extortion group, Helix, is reportedly conducting targeted campaigns by exploiting identity-based attack techniques to gain access to Microsoft 365 environments and exfiltrate data from SharePoint Online. The group leverages voice phishing (vishing), device code phishing, and multi-factor authentication (MFA) abuse to compromise user accounts and establish unauthorized access. 

  • Helix threat actors reportedly initiate intrusions through vishing campaigns, impersonating trusted individuals—often the target's manager—and leveraging caller ID spoofing to enhance credibility. 


  • The actors then attempt to persuade victims to complete device code phishing workflows, enabling unauthorized access to corporate accounts and Microsoft 365 resources. 


  • Following successful authentication, the actors conduct reconnaissance and enumeration of SharePoint environments before identifying and exfiltrating sensitive data for extortion purposes. 


  • Helix's variable dwell times suggest a flexible, target-specific operational approach, enabling the group to adapt its intrusion timeline to victim environments to maximize data theft and extortion opportunities while minimizing the likelihood of detection. Helix's operations also appear to be focused on large-scale data theft and extortion, with an emphasis on automated SharePoint data exfiltration following successful credential or session compromise.

Overlaps with Other Extortion Groups

Researchers assess that Helix likely emerged from or has operational overlap with the ShinyHunters and BlackFile/Redact cybercriminal ecosystems. ShinyHunters historically focuses on compromising websites, developer repositories, and exposed credentials or API keys to gain access to corporate cloud environments, monetizing stolen victim data on the dark web. BlackFile utilizes identity-centric and social engineering–driven methods of intrusion, relying less on traditional malware and instead leveraging credential theft, privilege escalation, rapid data exfiltration, and coercive tactics such as swatting to maximize extortion pressure. In May 2026, BlackFile announced that it would be rebranding as “Redact” (which may have later rebranded again to “Pink”), yet despite the rebrands, threat actors operating within these groups continued to exhibit similar operational models, victimology, and extortion methodologies.  

Analyst Comments

Collectively, the similarities between the groups suggest the possibility of a shared criminal ecosystem, affiliate network, or loosely connected threat cluster rather than entirely independent operations.  The emergence of Helix further reflects the broader trend of extortion groups rebranding or fragmenting while retaining proven attack techniques and operational infrastructure to support their criminal activities. Despite suspicion of these groups’ connectivity, the exact nature of the relationship remains unconfirmed.  As Helix focuses on identity-based attack techniques to gain access to Microsoft 365 environments, Arete recommends that organizations remain vigilant in using MFA, enforcing strong identity security controls, continuously monitoring authentication activity, and enhancing user awareness of social engineering tactics.

  • Sources

  • Helix, a New Name in the Data Extortion Ecosystem?

  • BlackFile actively extorting data-theft victims in retail and hospitality sector

  • "Pink" Data Extortion Group Hunting With Evasive Phishing Kits