Article

Avaddon Ransomware Hits AXA

May 28, 2021

Arete Analysis

Combating Ransomware

Endpoint Detection and Response

Summary

Avaddon ransomware allegedly attacked European insurance provider AXA shortly after the company announced that it will stop paying ransoms for its clients. Our analysis provides an in-depth look at Avaddon’s tactics and recommended mitigations.

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From September 2020 to May 2021, Arete responded to nine Avaddon ransomware engagements across varying industry sectors, including professional services, financial services, healthcare, hospitality, public services, and retail.

During the first week of May, Arete received an FBI Liaison Alert System (FLASH) CU-000145-MW from the FBI Cyber Division. The Australian Cyber Security Center (ACSC) also released an alert about an ongoing Avaddon ransomware campaign.

According to reports, at the beginning of May 2021, AXA (one of Europe’s top five insurers) said it will stop reimbursing people in France who pay ransoms after cybercriminals target them with ransomware. It will also stop writing cyber insurance policies that cover customers for extortion payments to ransomware attackers. This decision is said to have come in response to concerns aired by French justice and cybersecurity officials during a recent senate roundtable in Paris about the global ransomware epidemic.

AXA has now found itself a victim of a ransomware breach. Public reports say that the Avaddon ransomware group has impacted AXA Asia Assistance IT operations in Thailand, Malaysia, Hong Kong, and the Philippines. The group claims to have stolen 3 terabytes of data, including ID cards, passport copies, customer claims, reserved agreements, denied reimbursements, payments to customers, contracts and reports, customer IDs, bank account scanned papers, hospital and doctor reserved material (private investigation for fraud), and customer medical reports, including HIV, hepatitis, STD, and other illness reports. According to reports, the ransomware group said AXA had 240 hours to communicate and cooperate or they would start leaking valuable company documents.

While the juxtaposition of the AXA decision to not pay ransoms for French victims or even write ransomware coverage in France could have motivated the attack, Arete has no information or evidence to link these events. In general, and as disclosed in publicly released news reports, attacks against insurance companies are increasing.

In a recent interview, a member of the REvil ransomware gang was asked if they target organizations with cyber insurance. His response:

“Yes, this is one of the tastiest morsels. Especially to hack the insurers first — to get their customer base and work in a targeted way from there. And after you go through the list, then hit the insurer themselves.”
- "Unknown" REvil Ransomware Representative

In its CU-000145-MW FLASH Alert, the FBI notified of activity by cyber actors using Avaddon ransomware-as-a-service (RaaS) to target U.S. and foreign private sector companies, manufacturing organizations, and healthcare agencies. The alert states that the threat actors:

Have compromised victims through remote access login credentials like remote desktop protocol (RDP) and virtual private network (VPN) with single-factor authentication or improperly configured RDP.
Once they gain access to a victim’s network, they map the network and identify backups for deletion and/or encryption. They use malware that escalates privileges, contains anti-analysis protection code, enables persistence on a victim system, and verifies the victim is not located in the Commonwealth of Independent States (CIS). Their ransomware terminates services and processes related to backup and antivirus running in system memory before encrypting victims’ data.
Encrypt and exfiltrate data from the victim network for extortion, threatening its release in their TOR leak site (avaddongun7rngel.onion) if victims don’t pay the ransom.
Will perform a 5% data leak if the ransom is not paid within three to five days and follow with a full leak of the data stolen if the ransom is not paid.
Announced in January 2021 that they would attack victims who do not pay ransoms with distributed denial-of-service (DDoS) attacks.
Have used the following IPs during RDP connections: 185.216.33.0/24, 45.145.67.0/23, 193.27.229.0/23, 217.8.117.63.

The ACSC report includes some of the following tactics, techniques, and procedures (TTPs):

Phishing and malicious email spam (malspam) campaigns to deliver malicious JavaScript files. These are often low in sophistication, containing a threat suggesting the attached file contains a compromising photo of the victim.
Using “double extortion” techniques as coercion and further pressure to pay a ransom, including:
- Threatening to publish the victim’s data via the Avaddon Data Leak Site (DLS): avaddongun7rngel.onion.
- Threatening the use of DDoS attacks against the victim (first identified in February 2021).
Identify the default geolocation and system language of the user’s device to determine whether the user will be targeted for attack or not.
Use of Windows Scheduled Task to establish persistence.

The report also includes the following information about countries and sectors affected by this threat:

Statistical Data on Avaddon Ransomware From Arete Metrics

The information listed is based on Avaddon cases investigated by Arete IR since September 2020. Our IR and Data Analytics practices work together to track key data points for every ransomware engagement, and our IR practice tracks data points on the ransomware variant and collects statistics based on handled engagements:

Arete has responded to nine Avaddon breach response engagements since September 2020 in the following sectors: Professional Services | Financial Services | Healthcare | Hospitality | Public Services | Retail
At victim/breach coach/carrier request, Arete negotiated and paid the ransom in four of the nine Avaddon cases. In the remaining five cases, we were able to assist the victim in recovering from backups.
Average ransom demand: US$1,089,375.
Maximum ransom demand: US$4,000,000.
Minimum ransom demand: US$15,000.
We observed data exfiltration in 67% of the incidents.
Phishing emails and RDP were the methods of infection 60% of the time.

During investigations, our incident responders have observed threat actors using RDP to remote into the victim environment. We have seen attackers use Mimikatz, Advanced Port Scanner, Advanced IP Scanner, PsExec, Rclone, Gmer, and svhost.exe. We have also seen exe_[victim_org].exe as the ransomware file names.

Mitigation Measures Recommended By The FBI and ACSC

Back up critical data offline.
Ensure copies of critical data are in the cloud or on an external hard drive or storage device.
Secure your backups and ensure data is not accessible for modification or deletion from the system where the data resides.
Use two-factor authentication with strong passwords, including for remote access services.
Monitor cyber threat reporting regarding the publication of compromised VPN login credentials and change passwords/settings, if applicable.
Regularly change passwords to critical systems.
Keep computers, devices, and applications patched and up to date.
Install and regularly update antivirus or antimalware software on all hosts.
Scan emails and attachments to detect and block malware.
Implement a training program and processes to identify phishing and externally sourced emails.

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Article

Mar 17, 2026

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

Mar 9, 2026

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

Mar 3, 2026

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

Article

Feb 20, 2026

Threat Actors Leveraging Gemini AI for All Attack Stages

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. According to the Google Threat Intelligence Group (GTIG), threat actors linked to the People’s Republic of China (PRC), Iran, North Korea, and other unattributed groups have misused Gemini to accelerate target profiling, synthesize open-source intelligence, identify official email addresses, map organizational structures, generate tailored phishing lures, translate content, conduct vulnerability testing, support coding tasks, and troubleshoot malware development. Cybercriminals are increasingly exploring AI-enabled tools and services to scale malicious activities, including social engineering campaigns such as ClickFix, demonstrating how generative AI is being integrated into both espionage and financially motivated threat operations.

What’s Notable and Unique

Threat actors are leveraging Gemini beyond basic reconnaissance, using it to generate polished, culturally nuanced phishing lures and sustain convincing multi-turn social engineering conversations that minimize traditional red flags.
In addition, threat actors rely on Gemini for vulnerability research, malware debugging, code generation, command-and-control development, and technical troubleshooting, with PRC groups emphasizing automation and vulnerability analysis, Iranian actors focusing on social engineering and malware development, and North Korean actors prioritizing high-fidelity target profiling.
Beyond direct operational support, adversaries have abused public generative AI platforms to host deceptive ClickFix instructions, tricking users into pasting malicious commands that deliver macOS variants of ATOMIC Stealer.
AI is also being integrated directly into malware development workflows, as seen with CoinBait’s AI-assisted phishing kit capabilities and HonestCue’s use of the Gemini API to dynamically generate and execute in-memory C# payloads.
Underground forums show strong demand for AI-powered offensive tools, with offerings like Xanthorox falsely marketed as custom AI but actually built on third-party commercial models integrated through open-source frameworks such as Crush, Hexstrike AI, LibreChat-AI, and Open WebUI, including Gemini.

Analyst Comments

The increasing misuse of generative AI platforms like Gemini highlights a rapidly evolving threat landscape in which state-backed and financially motivated actors leverage AI as a force multiplier for reconnaissance, phishing, malware development, and post-compromise operations. At the same time, large-scale model extraction attempts and API abuse demonstrate emerging risks to AI service integrity, intellectual property, and the broader AI-as-a-Service ecosystem. While these developments underscore the scalability and sophistication of AI-enabled threats, continued enforcement actions, strengthened safeguards, and proactive security testing by providers reflect ongoing efforts to mitigate abuse and adapt defenses in response to increasingly AI-driven adversaries.

Sources

GTIG AI Threat Tracker: Distillation, Experimentation, and (Continued) Integration of AI for Adversarial Use