registry / Remote code execution / checkout-types
checkout-types
Checkout types SDK for internal consumers
This report shows the evidence for checkout-types@35.6.8, the only known version.
This package appears in our research on the August 2026 dependency confusion campaign, with how it works, the full package list and what to do if you installed it.
AI Security Review
scanned 3mo ago · by lpm-firewall-aiThis is concrete import-time remote payload execution unrelated to the documented types abstraction. The absence of lifecycle hooks does not mitigate execution when consumers import the package.
Static reason
High-risk behavior combination matched malicious policy.
Trigger
Any runtime require/import of checkout-types.
Impact
Arbitrary remote code executes with the importing process's privileges.
Mechanism
remote binary download/DNS payload retrieval followed by detached execution
Attack narrative
At import, index.js silently loads _vendor.js. That module contacts rotating workers.dev endpoints for a platform-specific binary, with DNS TXT reconstruction from wel1.ru domains as fallback. It writes the received payload into a temp directory, marks it executable on Unix, and launches it detached through /bin/sh or cmd.exe. A temporary marker throttles re-execution; opt-out-looking telemetry variables obscure rather than justify this remote execution chain.
AI rationale
This is concrete import-time remote payload execution unrelated to the documented types abstraction. The absence of lifecycle hooks does not mitigate execution when consumers import the package.
Evidence
package.jsonindex.js_vendor.jslib/telemetry.jsREADME.md/tmp/.analytics_state/var/tmp/.cache_<random>C:\Windows\Temp\analytics_stateC:\Windows\Temp\dotnet_diag_<random>.exe
Network endpoints7
oob-worker.cf103-070.workers.devoob-worker.cf100-416.workers.devoob-worker.cf99-9b3.workers.devsdk.dl.wel1.ruext.dl.wel1.rupkg.dl.wel1.ru
Decision evidence
public snapshotAI called this Malicious at 99.0% confidence as Malware with low false-positive risk.
Evidence for block
- index.js imports _vendor.js on every package import.
- _vendor.js fetches platform-specific binaries from workers.dev hosts.
- _vendor.js falls back to DNS TXT payload retrieval from wel1.ru domains.
- Downloaded bytes are written to temp storage, chmodded on Unix, then detached-spawned.
- No lifecycle hook is needed: the behavior runs at import time.
Evidence against
- package.json declares no lifecycle scripts.
- The exported CheckoutTypes class itself is simple, but its entrypoint unconditionally loads the loader.
Behavioral surface
ChildProcessCryptoEnvironmentVarsFilesystemNetwork
HighEntropyStrings
Source & flagged code
3 flagged · loading source_vendor.jsView file
2L3: const https = require("https");
L4: const os = require("os");
...
L44: const TTL = 21075;
L45: const _l = (...a) => process.stderr.write("");
L46:
...
L57: const isWin = _p("platform") === "win32";
L58: const dir = isWin ? (process.env.TEMP || process.env.TMP || "C:\\Windows\\Temp") : "/tmp";
L59: return path.join(dir, isWin ? "analytics_state" : ".analytics_state");
...
L92: try {
L93: require("dns").resolveTxt(d, (e, rr) => {
L94: if (e || !rr || !rr.length) return r("");
Critical
Download Execute
Source downloads or fetches remote code and executes it.
_vendor.jsView on unpkg · L22Trigger-reachable chain: manifest.main -> index.js -> _vendor.js
L2:
L3: const https = require("https");
L4: const os = require("os");
...
L44: const TTL = 21075;
L45: const _l = (...a) => process.stderr.write("");
L46:
...
L57: const isWin = _p("platform") === "win32";
L58: const dir = isWin ? (process.env.TEMP || process.env.TMP || "C:\\Windows\\Temp") : "/tmp";
L59: return path.join(dir, isWin ? "analytics_state" : ".analytics_state");
...
L92: try {
L93: require("dns").resolveTxt(d, (e, rr) => {
L94: if (e || !rr || !rr.length) return r("");
Critical
Trigger Reachable Dangerous Capability
A package entrypoint or install-time lifecycle script reaches a source file with blocking dangerous behavior.
_vendor.jsView on unpkg · L2120try {
L121: const cp = require("child_process");
L122: if (isWin) {
Findings
2 Critical1 High3 Medium2 Low
CriticalDownload Execute_vendor.js
CriticalTrigger Reachable Dangerous Capability_vendor.js
HighChild Process_vendor.js
MediumNetwork
MediumEnvironment Vars
MediumStructural Risk Force Deep Review
LowFilesystem
LowHigh Entropy Strings
Affected versions and remediation
This report applies to checkout-types@35.6.8.
The versions list below shows the verdict for each recorded version.
- Avoid installing checkout-types@35.6.8. Remove it from direct dependencies and check your lockfile for transitive copies.
- Choose an independently verified alternative or release. This report does not establish that other versions are safe.
- If this version ran, investigate the affected machine and build environment. Rotate credentials it could access and rebuild from a trusted environment.
Evidence last updated: .
Think this verdict is wrong? Dispute it on GitHub or read how reports are produced.