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easy-day-js / Mastra npm Supply Chain Attack

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[AI-DRAFTED · AWAITING VERIFICATION]

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Summary

On June 16–17, 2026, attackers published a typosquatted npm package named easy-day-js mimicking the legitimate dayjs date library, then used a hijacked former-contributor npm account (ehindero) to inject it as a dependency across 141–144 packages in the @mastra organization within an 88-minute window. The malicious postinstall payload functioned as a cross-platform remote access trojan (RAT) and infostealer, exfiltrating cryptocurrency wallet credentials, browser history, and developer secrets before self-deleting, with affected packages carrying a combined weekly download count exceeding 1.1 million.

Connected Entities

1 entity

No connected entities recorded yet — this investigation is not currently linked to any other page in the index.

Have evidence about easy-day-js / Mastra npm Supply Chain Attack?

Timeline(8 events)

29 May 2026

An identical loader to the easy-day-js dropper was detected on public malware sandboxes, approximately 19 days before the Mastra attack, indicating prior toolkit testing or use.

JFrog Security Research

16 June 2026

npm account sergey2016 published easy-day-js@1.11.21 at 07:05 UTC — a clean, fully functional copy of the legitimate dayjs library with no malicious code, establishing a credible package history.

StepSecurity / JFrog

17 June 2026

easy-day-js@1.11.22 published at 01:01 UTC by sergey2016 with obfuscated malicious postinstall dropper (setup.cjs). TLS verification disabled; C2 download from 23.254.164.92:8000.

StepSecurity / Socket

17 June 2026

Beginning at 01:12 UTC, compromised ehindero account mass-published 141–144 trojanized @mastra packages over 88 minutes (through approximately 02:39 UTC), each listing easy-day-js@^1.11.21 as a dependency.

Socket / StepSecurity

17 June 2026

Mastra team became aware of the attack at approximately 8:45 PM PT (June 16 US time) and contacted npm and Socket Security. Began unpublishing compromised packages.

Mastra GitHub Issue #18061

17 June 2026

By 11:57 PM PT: 110 malicious packages unpublished; 6 packages deprecated (npm prevented full unpublishing). Safe versions published via PR #18056 around 1:00 AM PT. MFA token bypass vulnerability removed.

Mastra GitHub Issue #18061

17 June 2026

Compromised maintainer confirmed as an active Mastra employee whose account was hijacked via social phishing through a fraudulent LinkedIn message. Attacker had changed the ehindero account email to ehindero2016@tutamail.com.

Mastra GitHub Issue #18061 / Snyk

17 June 2026

Multiple security firms (StepSecurity, Socket, OX Security, JFrog, Snyk, Phoenix Security) published public technical analyses of the attack. JFrog flagged all compromised versions within 24 hours of detection.

Multiple security research firms
Provenance & Audit Trail

Decision Log

This investigation is cryptographically anchored to the Solana blockchain (1 event). 10 of 10 cited source URLs have an Internet Archive snapshot.

model: claude-sonnet-4-6

generated: 6/17/2026, 5:03:53 PM

last updated: 7/27/2026, 1:22:49 PM

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