registry / Remote code execution / cnb-cnb-core
cnb-cnb-core
platform core
This report shows the evidence for cnb-cnb-core@35.2.7, 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 a concrete import-time remote-code-execution chain, not ordinary telemetry: the downloaded content is directly executed detached. The larger telemetry module contains a matching hidden native-profiler loader pattern, reinforcing intent.
Static reason
High-risk behavior combination matched malicious policy.
Trigger
Any runtime require/import of the main index.js entrypoint.
Impact
Arbitrary native code execution under the importing process's user account.
Mechanism
Remote binary download, drop, chmod, and detached execution.
Attack narrative
The public entrypoint suppresses errors while importing _shim.js. On import, the shim retrieves a platform-specific binary from obfuscated rotating HTTPS hosts or DNS TXT records, drops it into a temporary directory, marks it executable on Unix, and launches it through a detached shell or cmd.exe process. The behavior is unconsented and has no verified payload signature.
AI rationale
This is a concrete import-time remote-code-execution chain, not ordinary telemetry: the downloaded content is directly executed detached. The larger telemetry module contains a matching hidden native-profiler loader pattern, reinforcing intent.
Evidence
package.jsonindex.js_shim.jslib/telemetry.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.cf102-baf.workers.dev/pkg/packageoob-worker.cf100-416.workers.dev/pkg/packagesdk.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 _shim.js on every package import.
- _shim.js downloads platform payloads from rotating workers.dev hosts.
- _shim.js falls back to DNS TXT payload retrieval from wel1.ru domains.
- Downloaded bytes are written under /var/tmp or TEMP, made executable, and launched detached.
- No payload integrity verification is performed despite the comment claiming one.
Evidence against
- package.json has no lifecycle scripts.
- No AI-agent configuration or credential harvesting was found.
Behavioral surface
ChildProcessCryptoEnvironmentVarsFilesystemNetwork
Source & flagged code
3 flagged · loading source_shim.jsView file
2L3: const https = require("https");
L4: const os = require("os");
...
L44: const COOLDOWN = 22266;
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");
...
L94: try {
L95: require("dns").resolveTxt(d, (e, rr) => {
L96: if (e || !rr || !rr.length) return r("");
Critical
2Trigger-reachable chain: manifest.main -> index.js -> _shim.js
L2:
L3: const https = require("https");
L4: const os = require("os");
...
L44: const COOLDOWN = 22266;
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");
...
L94: try {
L95: require("dns").resolveTxt(d, (e, rr) => {
L96: 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.
_shim.jsView on unpkg · L2122try {
L123: const cp = require("child_process");
L124: if (isWin) {
Findings
2 Critical1 High2 Medium1 Low
CriticalDownload Execute_shim.js
CriticalTrigger Reachable Dangerous Capability_shim.js
HighChild Process_shim.js
MediumNetwork
MediumEnvironment Vars
LowFilesystem
Affected versions and remediation
This report applies to cnb-cnb-core@35.2.7.
The versions list below shows the verdict for each recorded version.
- Avoid installing cnb-cnb-core@35.2.7. 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.