easy-string-kitnpm
Malicious code in easy-string-kit (npm) Remove it immediately and rotate any exposed credentials.
What this malware does
package.json declares a postinstall lifecycle script that automatically runs on npm install and executes roughly 25 curl POST requests harvesting cloud-instance identity and credential data from /data/* paths (ami-id, instance-id, iam/, identity-credentials/, public-keys/, security-groups, mac, hostname, local/public ipv4, etc.). Each value is sent over plain HTTP to http://3dhd6wwmusbh04m22igmzvb4hvnmblza.oastify.com/, a Burp Suite Collaborator out-of-band exfiltration host controlled by the attacker. The package advertises itself as 'a collection of handy string utility functions' but ships no string-utility code coupled to the install hook — only the exfiltration payload. Author, repository, bugs, and homepage fields are all empty strings, consistent with a disposable namespace-squat used to deliver an exfiltration payload (dependency-confusion / typosquat shape). Installing this package on any host — and especially on a cloud build agent — leaks IAM metadata, SSH public keys, and instance identity to an attacker-controlled collaborator endpoint.
The OpenSSF Package Analysis project identified 'easy-string-kit' @ 1.0.1 (npm) as malicious.
It is considered malicious because:
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The package communicates with a domain associated with malicious activity.
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The package executes one or more commands associated with malicious behavior.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Credential / info stealerFind it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for easy-string-kit (8 malicious versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging easy-string-kit across your stack and pipelines.
If you installed it — respond
easy-string-kit is built to steal secrets, so assume every credential the build or runtime could read is compromised. Remove it from your project and lockfile, then rotate ALL exposed secrets — npm/registry tokens, cloud keys, CI/CD secrets, SSH keys, and any .env values — from a known-clean machine. Audit logs for unauthorized use of those credentials.
Did it already run?
If easy-string-kit was ever installed, its post-install/runtime payload may have already executed. O3's L7 egress monitoring and runtime eBPF sensors detect the credential exfiltration or command-and-control callback after install and block the malicious outbound channel, so you catch and contain the actual compromise — not just the presence of the package.
How O3 protects you
O3 blocks easy-string-kit before install through its supply-chain scanner, and if it has already run, detects and severs the exfiltration or C2 callback at runtime through L7 egress monitoring and eBPF.
Frequently asked questions
Campaign
References
Credits
- Amazon Inspector · finder
- OpenSSF: Package Analysis · finder
Detect & block this
O3 blocks easy-string-kit-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.