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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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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