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Suspected North Korean Actors Pull off the Largest Crypto Heist in History

Arete Analysis

Threat Actors

On February 21st, 2025, approximately $1.4 billion USD in Ethereum was stolen from cryptocurrency exchange Bybit. Ethereum held a price of $2600 per token as of February 21st and is one of many cryptocurrencies the exchange holds. Some quick division shows that at least 500,000 Ethereum coins were stolen, making this the largest crypto heist to date in value. Both TRM Labs and Chainalysis have assessed the threat actor to be associated with North Korea with high confidence due to an overlap in crypto wallets tracked as belonging to North Korea.

What’s notable and unique?

  • North Korea has a long history of financial fraud, money laundering, and other illicit activity. Members of the Democratic People’s Republic of Korea (DPRK) military regularly participate in illicit activities, including remote worker fraud, cryptocurrency hijacking and mining, money mules, wire fraud, and even ransomware. These cybercriminal activities allow DPRK to bypass international sanctions to raise funds for their military.

  • The threat actors compromised one of Bybit’s offline cold wallets, digital wallets that store private keys needed to access other cryptocurrency wallets completely offline. Due to the wallet being disconnected from the internet, the most likely sources of the compromise were a supply chain attack, insider threat, or a private key compromise.

  • The alleged North Korean threat actors may not be able to fully monetize the theft. The funds must now be laundered before being taken out at another exchange, as most of the initial wallets to which funds were transferred have been marked as having stolen funds on legitimate cryptocurrency exchanges. The laundering will likely be a two-step process. First, the funds will be exchanged for a native cryptocurrency, such as Ether or BTC, as it is difficult to track stolen funds across cryptocurrency blockchain transfers. Next, the actors will attempt to cover their tracks further by layering the funds to throw investigators off their trail. Shortly after the compromise the actor used 50 wallets and placed 10,000 coins in each, further supporting the alleged theft of 500,000 coins in total.

  • Bybit has offered a 10% bounty on the stolen coins, leading to a potential purse of $140 million. So far, $42.89 million of the stolen funds have been frozen. However, it is unclear whether this is the work of bounty hunters, law enforcement, or Bybit.

Conclusion

While crypto-related attacks may seem like a new concept at face value, this is the most recent heist in a string traversing ten years. In 2024 alone, North Korean threat actors were associated with $1.5 billion out of $2.2 billion in theft. With North Korea conducting these thefts, the funds enter a broader cybercriminal ecosystem, increasingly invading the insurance ecosystem. Most recently, these threats have expanded into North Koreans fraudulently joining North American and European companies, stealing their source code, and then extorting the companies. Funds stolen in cryptocurrency thefts like the Bybit thefts are funding infrastructure supporting this increasingly stealthy form of extortion, consequently resulting in funds supporting the North Korean military.

Fortunately, as threat actors and money launderers strengthen their ability to hide stolen money, blockchain analytic techniques and toolsets have also evolved. Often, the best way to prevent crypto heists and cybercrime is to implement sound security principles, including password management, vulnerability patching, and end user training.

Sources

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Article

FortiBleed Campaign Linked to INC and Lynx Ransomware Operations

Researchers have linked the FortiBleed credential-harvesting campaign to the INC and Lynx ransomware-as-a-service (RaaS) operations, establishing a direct connection between large-scale FortiGate credential theft and subsequent ransomware deployment. The attribution is based on a variety of factors, including an operator observed managing negotiation panels for both ransomware groups, notable overlap between FortiBleed victim data and subsequent ransomware targets, and internal infrastructure exposing attack workflows. The campaign is estimated to have targeted more than 430,000 internet-facing FortiGate devices, resulting in administrative access to hundreds of organizations. 

What’s Notable and Unique

  • Researchers identified a shared operator actively managing negotiation panels for both the INC and Lynx ransomware groups, providing rare operational evidence linking the two RaaS operations beyond infrastructure or malware similarities. 


  • Analysis of the exposed infrastructure revealed a structured ransomware operation with dedicated roles for access acquisition, victim management, negotiations, and technical support, reflecting an organized ransomware-as-a-service (RaaS) model rather than an ad hoc criminal group. 


  • The operation reportedly integrates artificial intelligence into multiple stages of the attack lifecycle, including vulnerability research, penetration testing, attack automation, and ransomware development, demonstrating the increasing adoption of AI to enhance offensive capabilities.

Mitigations

Organizations should assume that exposed or previously compromised FortiGate credentials may be leveraged for ransomware deployment and immediately reset administrative and VPN credentials while enforcing multi-factor authentication (MFA) for all privileged access. Security teams should ensure that FortiGate appliances are fully patched, restrict management interfaces to trusted networks, and audit administrative accounts and firewall configurations for unauthorized changes. Organizations should also monitor for anomalous authentication activity, hunt for published indicators of compromise (IOCs), and review VPN and firewall logs for signs of unauthorized access. Maintaining centralized logging and a well-practiced incident response process can help detect and contain attacks before they progress to lateral movement or ransomware deployment.

Analyst Comments

The attribution of FortiBleed to the INC and Lynx ransomware operations reinforces the growing convergence between credential-harvesting campaigns and ransomware deployment, highlighting the role of initial access operations in modern RaaS ecosystems. The relationship between INC and Lynx also aligns with Arete's previous research, which identified a shared malware lineage. INC Ransom, first observed in 2023, was later leaked or sold, enabling code reuse by other threat actors. Lynx, which emerged in 2024, is widely regarded as an evolution of the INC codebase. Sinobi ransomware, identified in 2025, shares near-identical binaries and infrastructure, and approximately 99% code similarity with Lynx. Further details on the code correlation between INC, Lynx, and Sinobi are available in Arete's 2025 Annual Report.

Sources

  • Is FortiBleed Linked to INC and Lynx Ransomware?   

  • FortiBleed credential-theft campaign linked to Lynx ransomware   

  • FortiBleed Unmasked: A Joint Operation by Lynx and INC Ransomware Groups   

  • FortiBleed Credential Theft Campaign Attributed to INC and Lynx Ransomware Groups  

Article

Ransomware Trends & Data Insights: June 2026

Although Akira was once again the most active ransomware threat in June, activity remained relatively distributed among multiple threat groups, with 17 unique threat groups observed throughout the month. Along with Akira, Qilin and INC Ransom remained active and were among the top five most active threat groups observed in June. Several new threat actors also emerged during the month, including KryBit, Settra, and Icarus.

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

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

  • In June, a threat actor calling themselves Icarus compromised and exfiltrated data from customers of the market intelligence platform Klue. Klue later confirmed the security incident, which involved attackers stealing OAuth tokens used to connect to customers' Salesforce environments, and reported that the threat actor was deleting the data stolen from affected Klue customers. In an odd twist, reports emerged of a second threat actor claiming to have compromised Icarus's infrastructure and attempting to re-extort Klue's customers. Regardless, the Klue breach highlights the growing threat of software-as-a-service (SaaS) supply chain compromises, particularly those exploiting OAuth tokens and trusted integrations to bypass traditional security controls.

  • In mid-June, security researchers identified a large-scale credential-harvesting and valid account abuse campaign dubbed “FortiBleed” that systematically targets internet-facing Fortinet FortiGate firewalls and SSL-VPN gateways, relying heavily on automated password spraying and configuration exfiltration rather than vulnerability exploitation. The scale of exposure and attack activity has been significant and globally distributed, with attackers collecting the login credentials of over 86,000 FortiGate devices across 194 countries. There is no singular ‘fix’ to mitigate the database exposure, and it is important that organizations work with their security teams, incident response providers, and other stakeholders to review environments holistically and monitor for signs of potentially unauthorized activity.

  • Multiple threat groups continue to leverage vulnerable drivers to bypass endpoint detection and response (EDR) solutions in a technique known as Bring Your Own Vulnerable Driver (BYOVD). Arete has observed Akira and DragonForce using the technique in multiple engagements, and The Gentlemen ransomware-as-a-service (RaaS) has also been observed using what researchers are calling "GentleKiller", a framework consisting of multiple variants that leverage vulnerable drivers and EDR-disabling utilities to target a wide range of endpoint security products.  

Sources

  • Arete Internal

Article

Update on FortiBleed Credential Exposure

Last week, security researchers identified a large-scale credential-harvesting and valid account abuse campaign dubbed “FortiBleed” that systematically targets internet-facing Fortinet FortiGate firewalls and SSL-VPN gateways. The campaign relies heavily on automated password spraying and configuration exfiltration rather than vulnerability exploitation.

  • Attackers first scan for exposed FortiGate devices and rank targets based on revenue. SSH brute-force attacks are used against admin accounts to gain initial access.

  • Following initial access, operators deploy stealthy packet-sniffing capabilities and establish external listening posts to receive harvested credentials and session data in near real time.

  • Observed post-exploitation activity strongly indicates pre-positioning for broader enterprise compromise, including lateral movement and potential ransomware deployment.

  • The scale of exposure and attack activity has been significant and globally distributed. The campaign has been ongoing since at least February 2026, with attackers collecting the login credentials of over 86,000 FortiGate devices across 194 nations.

How Arete Can Help

Arete continues to monitor this campaign, utilizing our extensive experience in detection, threat hunting, and attack surface review to look for indications of unauthorized activity related to this database exposure. Additional information regarding important considerations, containment and credential compromise mitigation actions, and additional hardening recommendations can be found in Arete’s FortiBleed Advisory.

Sources

  • FortiBleed: SOCRadar’s Investigation into 86,644 Compromised Fortinet Firewalls

  • FortiBleed Attackers Turn Firewalls Into Credential Stealers as Heists Persist

  • FortiBleed: The Most Detailed Breakdown Yet of an Active Russian Credential-Harvesting Operation

  • Hackers Using FortigateSniffer Tool That Turns Compromised Firewalls Into Password Collectors  

Article

Europol Disrupts AudiA6 Crypto Laundering Service

European authorities have dismantled AudiA6, a major cryptocurrency laundering service linked to ransomware groups and broader cybercriminal networks. Between 2022 and 2025, the platform is believed to have processed over €336 million in illicit funds, enabling threat actors to obscure financial trails and monetize cybercrime proceeds. Its operators are also suspected of running Dark2Web, a dark web forum that facilitated collaboration, services, and connections among cybercriminals globally. This development underscores the expanding role of sophisticated, large-scale cryptocurrency laundering services in sustaining the cybercrime economy, enabling threat actors to obscure illicit funds and evade regulatory controls.

What’s Notable and Unique 

  • Following law enforcement disruption of Cryptex and Garantex, AudiA6 emerged as another platform involved in financial activities linked to ransomware groups. Investigators believe that AudiA6 became a central hub for cybercriminals seeking to launder stolen digital assets while obscuring the transaction trail from authorities.

  • On June 10, 2026, a coordinated operation resulted in two arrests in Georgia, the dismantling of key infrastructure (30+ servers, 25 domains), the freezing or seizure of over €778,000 in crypto, and the takedown of the AudiA6 and Dark2Web platforms. 

Analyst Comments

Ransomware groups and cybercriminal networks are increasingly leveraging sophisticated techniques, including chain-hopping, decentralized exchanges, and mixer-as-a-service platforms, to rapidly move illicit cryptocurrency across multiple blockchains, effectively obscuring transaction trails. Concurrently, the widespread use of fraudulent exchange accounts, mule wallets, and privacy-enhancing tools has elevated cryptocurrency laundering to a core enabler of the cybercrime ecosystem, allowing actors to bypass anti-money-laundering controls at scale. This investigation identified over 6,000 KYC records linked to money-mule accounts, many of which were tied to Russian-speaking intermediaries specifically recruited to facilitate the movement of illicit proceeds. These threat actors systematically used both commercial and domain-controlled email services to establish mule accounts across multiple cryptocurrency platforms. Collectively, these findings underscore the growing scale, coordination, and professionalization of cryptocurrency-enabled crime, highlighting the critical need for sustained, intelligence-led, and internationally coordinated efforts to disrupt these evolving financial ecosystems.

Sources

  • Ransomware gangs cut off from EUR 336 million ‘AudiA6’ crypto laundering pipeline