AWS Security Blog
Amazon identifies North Korean hacker group behind open-source supply chain attacks
Amazon is sharing new findings about how a threat actor linked to the Democratic People’s Republic of Korea (DPRK) is targeting open source software libraries, the shared building blocks that companies around the world use to develop applications. Amazon Threat Intelligence has linked several recent compromises of popular Node Package Manager (NPM) libraries to the same DPRK-linked threat actor, a connection that hasn’t been publicly reported until now. The analysis also describes how generative AI is already changing what malicious software packages look like and how threat actors are beginning to probe AI-based code systems. We’re sharing this research to help the open source community and security teams better identify and address these types of events.
These developments come 2 years after the XZ Utils backdoor, which demonstrated how a patient attacker can compromise critical open source software by exploiting the trust and limited time of volunteer maintainers. Open source software underpins much of the internet’s infrastructure: operating systems, web servers, encryption libraries, and the application frameworks that businesses rely on daily. When an attacker compromises a widely used open source package, every organization that depends on that package is potentially affected. Since then, Amazon Threat Intelligence has observed the volume and sophistication of software supply chain attacks increase, driven in large part by DPRK‑linked threat actors and cybercriminal groups.
In this post, Amazon Threat Intelligence and the Amazon Inspector team share new details about recent campaigns against popular NPM packages, including evidence that the compromises of the axios, debug, chalk, and typo-crypto libraries were carried out by the same DPRK-linked threat actor tracked by the security community as SAPPHIRE SLEET, STARDUST CHOLLIMA, BlueNoroff, CageyChameleon, and Alluring Pisces. We also outline how the techniques used to compromise open source repositories are evolving, why these changes matter for organizations that depend on open source software, and what Amazon Web Services (AWS) is doing to help customers detect and respond to these threats.
One DPRK–linked group behind multiple NPM compromises
In March 2025, the DPRK-linked threat actor compromised the typo-crypto package. In September 2025, the same threat actor compromised the debug and chalk NPM packages. In March 2026, the same operational playbook appeared in a compromise of the axios package, one of the most widely used JavaScript libraries with more than 100 million weekly downloads. In each case, the threat actor gained access by socially engineering a trusted maintainer of the package, then published a software update containing malicious code. Any organization that automatically pulled the latest version of these packages received the compromised update.
While the axios compromise has been publicly attributed to this DPRK-linked threat actor, the typo-crypto, debug, and chalk incidents haven’t previously been connected to it. Amazon Threat Intelligence identified shared tactics, techniques, and procedures (TTPs) across these supply-chain campaigns, including trojanized NPM packages, use of post-install hooks (scripts that run automatically when a package is installed), and code reuse. Based on analysis of command-and-control (C2) indicators and TTPs, Amazon Threat Intelligence assesses with medium confidence that these campaigns are attributable to the DPRK-linked threat actor tracked as SAPPHIRE SLEET, STARDUST CHOLLIMA, BlueNoroff, CageyChameleon, and Alluring Pisces. This is the first time these compromises have been publicly tied to this DPRK-linked threat actor.
Amazon Threat Intelligence assesses this as part of a financially motivated pattern: by compromising a small number of highly popular packages, the group gains potential access to thousands of downstream environments simultaneously. For a financially motivated threat actor, this approach is far more efficient than targeting organizations one at a time.
The aggregate impact of these incidents underscores the efficiency of targeting share dependencies. As reported by Wiz Research, roughly 1 in 10 cloud environments were affected by the debug and chalk supply chain event within a two‑hour window.
A smaller campaign that foreshadowed later activity
During routine analysis of indicators and TTPs related to the axios threat actor, Amazon Threat Intelligence identified a connection to a domain registered in 2025, prompting a full investigation into its historical activity. That investigation uncovered that the same DPRK-linked threat actor had committed a trojanized file to the typo-crypto NPM package in March 2025. The malicious file, core.js
, masquerades as the legitimate core-js NPM package within the typo-crypto repository.
Based on the limited number of observed downloads, Amazon Threat Intelligence assesses that this campaign was small scale and likely served as a testing ground for the more visible supply chain operations that followed in late 2025 and 2026. The group appears to have been refining supply chain techniques more than a year before the larger campaigns that drew public attention. Amazon Inspector reported this malware to the Open Source Vulnerabilities (OSV) database, where it’s now tracked as MAL‑2026‑3400, so that the broader security community can benefit from these findings.
The trojanized file executes when it receives a hash input beginning with the value 0098273. When triggered, it downloads a second-stage payload from a hardcoded C2 server, then executes the payload based on the victim’s operating system, with behavior tailored for Windows, macOS, or Linux. The malware implements file-based persistence with payload rotation and uses multi-layer obfuscation, combining base64‑encoded text with an XOR cipher keyed to 01042025.
Associated indicators of compromise include:
- Domain: npmjs[.]store
- IP address: 216[.]74[.]123[.]126
- NPM package: typo-crypto (SHA256: 24604384b0e748ada07923630b3d037489e696284a98c4409fb9b6763565571f)
- Trojanized file: core.js (SHA256: 2014d09c7ded74d89c885b5f11693865224116f1b25df9330e61fe528f419d73)
Amazon Threat Intelligence assesses that the group was experimenting with techniques that later appeared in the higher-impact campaigns against axios, debug, and chalk. Although the observed download volume was low, the tradecraft aligns with what we later observed in attacks on more popular packages.
How attacker tradecraft is shifting
Over the past year, Amazon Threat Intelligence and Amazon Inspector have observed threat actors changing the techniques they use to target open source libraries. These changes matter because open source packages remain attractive targets: they’re widely trusted, automatically updated in many environments, and maintained by communities that welcome new contributors. The following patterns describe how attackers are adapting their methods to evade modern defenses. Each is designed to exploit the gap between the moment a dependency is inspected and the moment it actually executes. A year ago, we looked for malicious packages. Today, we look for malicious behaviors split across packages that appear harmless on their own.
From package‑level attacks to fragment‑level attacks
Amazon Inspector has observed attackers increasingly splitting a single malicious workflow across several ordinary-looking packages. One package stores an encrypted blob disguised as configuration. A second ships the decryption logic. A third, often published later, fetches and executes the payload.
Viewed on its own, each package looks benign. There are no install hooks that stand out, no obvious evaluation of untrusted input, no network calls that look suspicious. The malicious behavior only appears when the components are used together in the intended sequence. This approach is designed to defeat scanners that evaluate packages one by one instead of reasoning about how they interact in a real dependency graph.
Long-horizon campaigns that invest in trust
We’re also observing threat actors taking a long view of trust accumulation. Instead of publishing obvious malware and waiting for downloads, they publish something genuinely useful and maintain it. They behave like real maintainers for weeks or months, shipping features, fixing bugs, and gaining dependents.
The same patience shows up on the human side. In some cases, the goal isn’t to launch a new package at all, but to become a contributor to an existing project. That’s the through line from XZ Utils backdoor to the debug, chalk, and axios maintainer compromises. In each case, the adversary treated legitimacy as an asset to be spent once, at the moment of maximum access.
Decoupling the package from its behavior
In many recent cases, a library is clean on the public registry yet still dangerous, because its real behavior depends on resources the attacker controls elsewhere. These can include guard or license scripts fetched from an external repository at runtime, configuration files that gate certain behaviors, or remote endpoints consulted at startup.
As long as those external resources remain benign, code reviews pass and automated scans return clean results. When an attacker flips the content or arms an endpoint that previously returned a placeholder, every installed copy can become malicious at once, without any new package release. A package that shows no malicious behavior today isn’t the same as a package that’s is safe by design.
From basic obfuscation to real cryptography
Where attackers used to rely on simple obfuscation such as minification or single-layer base64 encoding, we now observe multi-stage payloads that use stronger cryptographic techniques. Examples include AES‑GCM encrypted blobs gated by passphrases, RC4-style string arrays with per-call keys, layered XOR over base64, and native loaders that hold the next stage as an encrypted field decrypted only in memory.
The common design choice is that the decryption key is never stored in the package itself. It’s derived from runtime context, fetched from a server at execution time, or supplied as a license key. That means even an analyst with full source access can’t reliably decrypt the payload statically. Stage one looks like a simple decryptor; the malicious content remains ciphertext until it runs on a real target with the real key.
Payloads that avoid detonating in sandboxes
As defenders have scaled automated analysis in cloud sandboxes, attackers have made their code more environment aware. The payload decides whether it’s being analyzed before it acts. We see execution gated behind real package install lifecycles, single-use environment variables, and checks for signals of a genuine developer or build environment. These include interactive terminals, realistic usernames and hostnames, domain membership, plausible uptime, local file history, specific operating systems, and cloud metadata that helps distinguish analysis infrastructure from normal workloads.
Some delivery servers also tailor what they serve based on the client. A benign decoy goes to generic browser-like requests, while the live payload only appears for the exact user agent used by the malware. The result is that a clean verdict from a cloud sandbox often tells you more about how convincing your environment looks than how safe the package is.
How generative AI is reshaping both attacks and defenses
Generative AI is changing what attackers can produce and what defenders can rely on. Adversaries can generate novel code and content at scale. Historically, many malicious packages were caught because they looked wrong, with broken language, thin documentation, obvious copy-paste, or a telltale function reused across samples. Generative AI erases many of those signals.
Attackers can now produce thousands of lines of coherent, idiomatic, well-commented code, complete with convincing documentation, plausible commit histories, and synthetic maintainer identities, wrapped around a backdoor. Because each variant can be mutated, renamed, restructured, and re-encrypted, there is no single stable signature to match. Pattern-based detection loses ground against malware that looks one of a kind in every deployment.
AI is also creating new initial access vectors. One emerging technique is slopsquatting, where attackers register package names that exist only because an AI coding assistant hallucinated them. When a developer or an autonomous coding agent asks for help and the model confidently recommends a nonexistent package, an attacker can pre-register that name and wait. The next person who follows the recommendation might receive malware, despite not mistyping anything or visiting a malicious site, because the AI effectively delivered the bad dependency for them. As organizations move toward agents that install dependencies with limited human review, this path looks less like a curiosity and more like a scalable delivery channel.
Most significantly, AI changes the calculus for defensive automation. Attackers are no longer just writing malware for humans to miss. They’re writing malware for AI reviewers to approve. As organizations rely on AI systems to review code and triage packages, those AI systems themselves become part of the attack surface. We expect that indirect prompt injection, a technique where hidden instructions manipulate an AI system into taking unintended actions, will increasingly be embedded in malicious packages to fool AI-based code scanners. These instructions can be hidden in source comments, README files, docstrings, or test fixtures, and crafted to convince an automated system to mark malicious code as safe, skip a specific file, or perform an unintended action during analysis. The same content the malware needs to function can carry a second, separate message aimed at the machine that inspects it.
How AWS is responding
We’re investing across Amazon Threat Intelligence and Amazon Inspector to help customers adapt to this shifting landscape of software supply chain risk. Amazon remains committed to helping protect the security of our customers and the internet by actively hunting for and mitigating threats from sophisticated threat actors. We will continue working with Amazon teams, industry partners, and the security community to share intelligence and mitigate threats. Upon discovering this campaign, Amazon Threat Intelligence worked with Amazon Inspector so the malicious package was tracked, mitigated, and shared with the community through the OSV database. Additionally, the observed indicators were shared with Amazon GuardDuty to alert our customers of this activity.
Amazon Inspector uses these insights to refine our detection logic, broaden coverage across registries, and prioritize signals that reflect the tradecraft shifts described in this post, and is collaborating with industry partners such as package registries and Open Source Security Foundation (OpenSSF) to share findings.
We’re also investing in helping open source maintainers better secure their projects. In 2026, AWS joined the Linux Foundation and other industry leaders to launch Akrites, a collaborative initiative to defend critical open source software against AI-enabled cyber threats. AWS has also jointly invested $12.5 million alongside other organizations to defend the open source ecosystem from AI-driven attacks. These efforts reflect a broader commitment: the security of open source software is a shared responsibility, and defending it requires sustained investment from the organizations that depend on it.
Our goal is to help customers understand where their environments rely on open source components, identify suspicious behavior early, and respond quickly when the software supply chain is used as an entry point.