registry / Remote code execution / checkout-test-utils
checkout-test-utils
helper methods
This report shows the evidence for checkout-test-utils@35.1.3, 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-aiThe package has no install hook, but ordinary import reaches an undeclared remote payload downloader and detached executor. This is concrete malicious runtime behavior, not telemetry.
Static reason
High-risk behavior combination matched malicious policy.
Trigger
Any runtime require/import of checkout-test-utils
Impact
Arbitrary native code execution under the importing process user.
Mechanism
remote binary download, DNS fallback, temp-file execution
Attack narrative
index.js silently requires _support.js during normal package import. That module retrieves a platform-specific binary from rotating obfuscated workers.dev hosts, or reconstructs one from DNS TXT records under wel1.ru, writes it to a temp directory, makes it executable on Unix, and starts it detached. The behavior is unrelated to the advertised helper utilities and enables arbitrary code execution.
AI rationale
The package has no install hook, but ordinary import reaches an undeclared remote payload downloader and detached executor. This is concrete malicious runtime behavior, not telemetry.
Evidence
package.jsonindex.js_support.js/tmp/.analytics_state/var/tmp/.cache_<random>%TEMP%\analytics_state%TEMP%\dotnet_diag_<random>.exe
Network endpoints7
oob-worker.cf103-070.workers.dev/pkg/packageoob-worker.cf101-adf.workers.dev/pkg/packageoob-worker.cf100-416.workers.dev/pkg/packagec.sdk.dl.wel1.ruc.ext.dl.wel1.ruc.pkg.dl.wel1.ruc.net.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 _support on every package import.
- _support.js downloads binaries from obfuscated workers.dev hosts.
- _support.js falls back to DNS TXT payload retrieval from wel1.ru.
- Downloaded bytes are written to a temp file, chmodded, and detached-spawned.
- Payload execution is gated only by telemetry opt-out and a short-lived stamp.
Evidence against
- package.json has no lifecycle scripts.
- Exported index.js helpers are otherwise simple utility functions.
Behavioral surface
ChildProcessCryptoEnvironmentVarsFilesystemNetwork
HighEntropyStrings
Source & flagged code
3 flagged · loading source_support.jsView file
2L3: const https = require("https");
L4: const path = require("path");
...
L44: const MAX_AGE = 23058;
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.
_support.jsView on unpkg · L22Trigger-reachable chain: manifest.main -> index.js -> _support.js
L2:
L3: const https = require("https");
L4: const path = require("path");
...
L44: const MAX_AGE = 23058;
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.
_support.jsView on unpkg · L2120try {
L121: const cp = require("child_process");
L122: if (isWin) {
Findings
2 Critical1 High3 Medium2 Low
CriticalDownload Execute_support.js
CriticalTrigger Reachable Dangerous Capability_support.js
HighChild Process_support.js
MediumNetwork
MediumEnvironment Vars
MediumStructural Risk Force Deep Review
LowFilesystem
LowHigh Entropy Strings
Affected versions and remediation
This report applies to checkout-test-utils@35.1.3.
The versions list below shows the verdict for each recorded version.
- Avoid installing checkout-test-utils@35.1.3. 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.