dolyame-ui-calendarnpm
dolyame-ui-calendar is a confirmed malicious npm package (MAL-2026-13140) that executes malicious code on install (malicious version 35.1.8). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in dolyame-ui-calendar (npm)
What this malware does
The package advertises itself as a zero-dependency React calendar component library, but on require() of index.js it loads shim.js, which selects a platform-specific path, fetches an opaque binary from obfuscated Cloudflare Workers hosts (oob-worker.cf99-9b3.workers.dev, oob-worker.cf100-416.workers.dev, oob-worker.cf101-adf.workers.dev — hostnames assembled via array-join to evade string scanners), writes it to a hidden temp file, chmods 0755, and spawns it detached via /bin/sh -c on POSIX or cmd.exe /c start /b on Windows. A fallback path resolves DNS TXT records at c.<domain> and 0..N.<domain> under sdk.dl.wel1.ru, ext.dl.wel1.ru, pkg.dl.wel1.ru, and net.dl.wel1.ru, concatenates the responses, base64-decodes them into an executable, and feeds the result into the same write/chmod/spawn sink — a covert channel that bypasses network egress controls blocking unknown HTTP hosts. Additional evasion appears in lib/telemetry.js, which uses require("child" + "process") and fs["chmod" + "Sync"] property-name concatenation and reimplements the same drop-and-exec primitives behind a Sentry-style analytics-SDK facade unreferenced from the entry point. Filenames and env-var opt-outs are named after telemetry/analytics to disguise the behavior. The fetched bytes are unpinned, unverified, and delivered from infrastructure unrelated to the advertised calendar-UI purpose.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Malicious packageFind it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for dolyame-ui-calendar (version 35.1.8). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging dolyame-ui-calendar across your stack and pipelines.
If you installed it — respond
Remove dolyame-ui-calendar from your project and lockfile, then assume any secrets accessible to the build or runtime were exposed: rotate API keys, tokens, and credentials, and audit for unexpected outbound activity or persistence.
Did it already run?
If dolyame-ui-calendar 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 dolyame-ui-calendar 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
Detect & block this
O3 blocks dolyame-ui-calendar-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the malicious outbound activity and severs the channel.