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Law Enforcement Actions Leave ALPHV/BlackCat Scrambling to Salvage Operations

Cyber Threats

Threat Actors

Combating Ransomware

Through a coordinated law enforcement effort spearheaded by the FBI, ALPHV/BlackCat infrastructure was disrupted on December 7, 2023, in an operation publicly announced on December 19, 2023. After terrorizing businesses and organizations for over two years, the notorious ransomware group may have finally met its match.

What happened to BlackCat’s Infrastructure?

On December 7, 2023, the data leak website for ALPHV/BlackCat went offline and remained offline for more than 30 hours. This is one of the most prolonged disruptions the group has faced, as it previously only experienced periodic outages due to technical hosting issues. The BlackCat data leak site came back online with all data from previous victims removed before apparently being taken down for good on December 19, 2023, when existing BlackCat branding was replaced by an FBI banner including a TOR-based tip line for information on BlackCat and its affiliates.

Figure 1: Law Enforcement Seizure Banner Displayed on Known ALPHV/BlackCat Data Leak Sites on December 19, 2023

The BlackCat Decryptor

Prior to the takedown of BlackCat’s infrastructure, law enforcement maintained access to the threat actor’s environment for months and was able to obtain victim-specific decryption keys to BlackCat’s ransomware executable by monitoring the environment. The FBI used these decryption keys to offer decryption to 500 BlackCat victims as the FBI neared publicizing the takedown. The FBI estimated they were able to save organizations a total of $68 million in ransom demands.

However, based on Arete data, this is likely a conservative number. With an average initial ransom demand of $2.28 million in 2023, BlackCat demands observed by Arete are significantly higher than the demands calculated by law enforcement. While ransom payments are often significantly discounted from the original $2.28 million demand following a negotiation process, it is possible that this action taken by law enforcement could have saved victim organizations as much as five times as what was assessed by the FBI. Alternatively, the gap between Arete and the FBI’s estimated ransom payments may indicate how many organizations had either already paid a ransom before the decryption keys were available or were able to recover without paying the ransom.

The After-Action Report

While the initial data leak site (DLS) disruption nearly two weeks ago caused BlackCat’s operations to decrease significantly, three new victims were posted to the DLS between when the site came back online and when it was finally seized by the FBI. In one of those postings, BlackCat claimed to have reported a new victim to the Securities and Exchange Commission (SEC). In the intervening period, Arete also responded to a BlackCat engagement in which the threat actors utilized an old BlackCat encryptor. Therefore, while the infrastructure takedown certainly disrupted the scale and speed of BlackCat operations, it did not stop the operations of all affiliates.  

Shortly after the FBI announced the website seizure on December 19, 2023, ALPHV/BlackCat’s operators stood up a new data leak site and claimed their website was “unseized.” Security researchers assess that BlackCat operators maintained access to the keys used to sign the original data leak site but lost access to their original servers. After standing up the new data leak site, BlackCat made a new post about a victim and stated they will no longer give victims additional time to conduct negotiations. The operators also stated they will harass executive teams and their children, report companies to the SEC and US Department of Health and Human Services (HHS), and release a clearnet (regular internet) link to data on victims.


Figure 2 ALPHV/BlackCat Post Excerpt Uploaded December 19, 2023

With a lack of trust in their own infrastructure, BlackCat affiliates began communicating with victims directly via email rather than relying on typical communication methods. While attempting to continue operations to the best of their ability, BlackCat operators reportedly later discovered that law enforcement gained access to a compromised domain controller and issued a concerning statement to their affiliates, giving them permission to “take the gloves off” in future operations.

The statement shared that all previously observed rules, minus the inability to target CIS* countries, no longer apply to BlackCat affiliates, and an increased percentage of ransom payments, now 90%, will go to affiliates. Additionally, several targets that were reportedly previously forbidden, such as hospitals and nuclear power plants, are now fair game for affiliates to target with the BlackCat encryptor. Finally, BlackCat stated they will no longer accept discounts from the original ransom demand. With an average negotiated discount of 63% off the original ransom demand observed by Arete, the inability to negotiate could cost BlackCat victims millions of dollars if they choose to make ransom payments.

Who is ALPHV/BlackCat?

ALPHV/BlackCat is a ransomware-as-a-service (RaaS) group that first emerged in November 2021. The group operates by providing ransomware software and infrastructure to other cybercriminals, who then use it to launch attacks on various targets. The group takes a cut of the ransom payments and leaks the stolen data of its victims on its Dark Web site. The group is also known for its unique extortion methods, which include reporting its victims to the SEC and creating false domains to impersonate victims and leak data.

Since its inception, ALPHV/BlackCat listed over 650 companies on its data leak site, making it one of the most prolific and dangerous ransomware groups active today. Throughout 2023, BlackCat was the most frequently observed ransomware group in Arete’s industry data. Among 56 different ransomware and extortion groups observed in 2023, BlackCat accounted for nearly a quarter of Arete’s overall engagements.

Figure 3: Visual from Arete’s Q3 2023 Crimeware Report

Affiliates of ALPHV/BlackCat include Scattered Spider, the ransomware group behind the brazen cyberattacks against MGM Resorts, Caesars, and more. The FBI and CISA issued a joint advisory about Scattered Spider in November 2023, warning of their use of ALPHV/BlackCat ransomware. 

What are the implications of this takedown? 

While the full implications of this takedown are currently unknown, it could have significant implications for the ransomware landscape. The takedown may disrupt the activities of many affiliates relying on ALPHV/BlackCat’s ransomware encryptor and infrastructure, likely forcing existing affiliates to move on to other ransomware programs or develop their own. Notably, LockBit ransomware quickly seized the opportunity to advertise that BlackCat affiliates could continue their current operations under LockBit’s RaaS operation. Additionally, this could lead to the emergence of new ransomware variants and groups, with affiliates bringing experience from previous programs. This happened before when law enforcement actions against other ransomware groups, such as DarkSide and REvil, resulted in the formation of new groups, like BlackMatter and Haron. Even before the FBI takedown, Arete observed a splintering of BlackCat affiliates, with groups like Scattered Spider conducting solo operations alongside operations using the BlackCat encryptor.  

While the takedown of ALPHV/BlackCat’s websites is a positive development in the fight against ransomware, it is not a definitive victory. Ransomware remains a persistent and evolving threat that requires constant vigilance and collaboration from all stakeholders, including governments, businesses, and individuals. 

BlackCat has been a widely impactful ransomware group, in part because it relied on affiliates with diverse means of compromising victims. Arete observed a wide variety of initial access measures in engagements involving ALPHV/BlackCat affiliates, including a sophisticated capability to exploit software and hardware vulnerabilities. Preventing BlackCat attacks and future ransomware attacks from affiliates that escape law enforcement requires a strong patch management program that prioritizes vulnerabilities with publicly released exploit code. Additionally, managing remote management tools in an environment is critical in preventing similar attacks. Arete identified third-party remote access tools as the initial intrusion method in more than eight percent of ALPHV/BlackCat engagements, but analysis of the full lifecycle of an ALPHV/BlackCat engagement showed those tools being used throughout the attacks to enable attacker operations. Neither method is unique to BlackCat operators and remains an important focus for defenders.   


Footnotes

*The Commonwealth of Independent States (CIS) is a regional intergovernmental organization formed following the dissolution of the Soviet Union, including Russia, Belarus, Kazakhstan, Moldova, Armenia, Tajikistan, Uzbekistan, Kyrgyzstan, Azerbaijan, and Turkmenistan.

 

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Red alert symbols and warning icons spreading across a digital network, representing firewall compromise and widespread cyber intrusion.
Red alert symbols and warning icons spreading across a digital network, representing firewall compromise and widespread cyber intrusion.

Article

FortiGate Exploits Enable Network Breaches and Credential Theft

A recent security report indicates that threat actors are actively exploiting FortiGate Next-Generation Firewall (NGFW) appliances as initial access vectors to compromise enterprise networks. The activity leverages recently disclosed vulnerabilities or weak credentials to gain unauthorized access and extract configuration files, which often contain sensitive information, including service account credentials and detailed network topology data. 

Analysis of these incidents shows significant variation in attacker dwell time, ranging from immediate lateral movement to delays of up to two months post-compromise. Since these appliances often integrate with authentication systems such as Active Directory and Lightweight Directory Access Protocol (LDAP), their compromise can grant attackers extensive access, substantially increasing the risk of widespread network intrusion and data exposure. 

What’s Notable and Unique 

  • The activity involves the exploitation of recently disclosed security vulnerabilities, including CVE-2025-59718, CVE-2025-59719, and CVE-2026-24858, or weak credentials, allowing attackers to gain administrative access, extract configuration files, and obtain service account credentials and network topology information. 


  • In one observed incident, attackers created a FortiGate admin account with unrestricted firewall rules and maintained access over time, consistent with initial access broker activity. After a couple of months, threat actors extracted and decrypted LDAP credentials to compromise Active Directory. 

  • In another case, attackers moved from FortiGate access to deploying remote access tools, including Pulseway and MeshAgent, while also utilizing cloud infrastructure such as Google Cloud Storage and Amazon Web Services (AWS). 

Analyst Comments 

Arete has identified multiple instances of Fortinet device exploitation for initial access, involving various threat actors, with the Qilin ransomware group notably leveraging Fortinet device exploits. Given their integration with systems like Active Directory, NGFW appliances remain high-value targets for both state-aligned and financially motivated actors. In parallel, Arete has observed recent dark web activity involving leaked FortiGate VPN access, further highlighting the expanding risk landscape. This aligns with the recent reporting from Amazon Threat Intelligence, which identified large-scale compromises of FortiGate devices driven by exposed management ports and weak authentication, rather than vulnerability exploitation. Overall, these developments underscore the increasing focus on network edge devices as entry points, reinforcing the need for organizations to strengthen authentication, restrict external exposure, and address fundamental security gaps to mitigate the risk of widespread compromise. 

Sources 

FortiGate Edge Intrusions | Stolen Service Accounts Lead to Rogue Workstations and Deep AD Compromise

Article

Vulnerability Discovered in Anthropic’s Claude Code

Security researchers discovered two critical vulnerabilities in Anthropic's agentic AI coding tool, Claude Code. The vulnerabilities, tracked as CVE-2025-59536 and CVE-2026-21852, allowed attackers to achieve remote code execution and to compromise a victim's API credentials. The vulnerabilities exploit maliciously crafted repository configurations to circumvent control mechanisms. It should be noted that Anthropic worked closely with the security researchers throughout the process, and the bugs were patched before the research was published. 

What’s Notable and Unique 

  • The configuration files .claude/settings.json and .mcp.json were repurposed to execute malicious commands. Because the configurations could be applied immediately upon starting Claude Code, the commands ran before the user could deny permissions via a dialogue prompt, or they bypassed the authentication prompt altogether. 


  • .claude/settings.json also defines the endpoint for all Claude Code API communications. By replacing the default localhost URL with a URL they own, an attacker could redirect traffic to infrastructure they control. Critically, the authentication traffic generated upon starting Claude Code included the user's full Anthropic API key in plain text and was sent before the user could interact with the trust dialogue. 


  • Restrictive permissions on sensitive files could be bypassed by simply prompting Claude Code to create a copy of the file's contents, which did not inherit the original file's permissions. A threat actor using a stolen API key could gain complete read and write access to all files within a workspace. 

Analyst Comments 

The vulnerabilities and attack paths detailed in the research illustrate the double-edged nature of AI tools. The speed, scale, and convenience characteristics that make AI tools attractive to developer teams also benefit threat actors who use them for nefarious purposes. Defenders should expect adversaries to continue seeking ways to exploit configurations and orchestration logic to increase the impact of their attacks. Organizations planning to implement AI development tools should prioritize AI supply-chain hygiene and CI/CD hardening practices. 

Sources 

  • Caught in the Hook: RCE and API Token Exfiltration Through Claude Code Project Files | CVE-2025-59536 | CVE-2026-21852

Article

Ransomware Trends & Data Insights: February 2026

After a slight lull in January, Akira and Qilin returned to dominating ransomware activity in February, collectively accounting for almost half of all engagements that month. The rest of the threat landscape remained relatively diverse, with a mix of persistent threats like INC and PLAY, older groups like Cl0p and LockBit, and newer groups like BravoX and Payouts King. Given current trends, the first quarter of 2026 will likely remain relatively predictable, with the top groups from the second half of 2025 continuing to operate at fairly consistent levels month to month.

Figure 1. Activity from the top 5 threat groups in February 2026

Throughout the month of February, analysts at Arete identified several trends behind the threat actors perpetrating cybercrime activities: 

  • In February, Arete observed Qilin actively targeting WatchGuard Firebox devices, especially those vulnerable to CVE-2025-14733, to gain initial access to victim environments. CVE-2025-14733 is a critical vulnerability in WatchGuard Fireware OS that allows a remote, unauthenticated threat actor to execute arbitrary code. In addition to upgrading WatchGuard devices to the latest Firebox OS version, which patches the bug, administrators are urged to rotate all shared secrets on affected devices that may have been compromised and may be used in future campaigns.


  • Reports from February suggest that threat actors are increasingly exploring AI-enabled tools and services to scale malicious activities, demonstrating how generative AI is being integrated into both espionage and financially motivated threat operations. The Google Threat Intelligence Group indicated that state-backed threat actors are leveraging Google’s Gemini AI as a force multiplier to support all stages of the cyberattack lifecycle, from reconnaissance to post-compromise operations. Separate reporting from Amazon Threat Intelligence identified a threat actor leveraging commercially available generative AI services to conduct a large-scale campaign against FortiGate firewalls, gaining access through weak or reused credentials protected only by single-factor authentication.


  • The Interlock ransomware group recently introduced a custom process-termination utility called “Hotta Killer,” designed to disable endpoint detection and response solutions during active intrusions. This tool exploits a zero-day vulnerability (CVE-2025-61155) in a gaming anti-cheat driver, marking a significant adaptation in the group’s operations against security tools like FortiEDR. Arete is actively monitoring this activity, which highlights the growing trend of Bring Your Own Vulnerable Driver (BYOVD) attacks, in which threat actors exploit legitimate, signed drivers to bypass and disable endpoint security controls.

Sources

  • Arete Internal

Article

ClickFix Campaign Delivers Custom RAT

Security researchers identified a sophisticated evolution of the ClickFix campaign that aims to compromise legitimate websites before delivering a five-stage malware chain, culminating in the deployment of MIMICRAT. MIMICRAT is a custom remote access trojan (RAT) written in the C/C++ programming language that offers various capabilities early in the attack lifecycle. The attack begins with victims visiting compromised websites, where JavaScript plugins load a fake Cloudflare verification that tricks users into executing a malicious PowerShell script, further displaying the prominence and effectiveness of ClickFix and its user interaction techniques. 

Not Your Average RAT 

MIMICRAT displays above-average defense evasion and sophistication, including: 

  • A five-stage PowerShell sequence beginning with Event Tracing for Windows and Anti-Malware Scan Interface bypasses, which are commonly used in red teaming for evading detection by EDR and AV toolsets.  

  • The malware later uses a lightweight scripting language that is scripted into memory, allowing malicious actions without files that could easily be detected by an EDR tool.  

  • MIMICRAT uses malleable Command and Control profiles, allowing for a constantly changing communication infrastructure. 

  • The campaign uses legitimate compromised infrastructure, rather than attacker-owned tools, and is prepped to use 17 different languages, which increases global reach and defense evasion. 

Analyst Comments 

The ClickFix social engineering technique remains an effective means for threat actors to obtain compromised credentials and initial access to victim environments, enabling them to deploy first-stage malware. Coupled with the sophisticated MIMICRAT RAT, the effectiveness of this campaign could increase. Arete will continue monitoring for changes to the ClickFix techniques, the deployment of MIMICRAT in other campaigns, and other pertinent information relating to the ongoing campaign. 

Sources 

  • MIMICRAT: ClickFix Campaign Delivers Custom RAT via Compromised Legitimate Websites