Article
Avaddon Ransomware Hits AXA
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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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.
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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
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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
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Figure 1. Activity from the top 5 threat groups in February 2026
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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