registry / Remote code execution / cobrowsing-test-utils
cobrowsing-test-utils
common helpers
This report shows the evidence for cobrowsing-test-utils@35.3.4, 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 import-reachable downloader and detached binary launcher are concrete malicious behavior, not telemetry. Absence of lifecycle hooks does not mitigate runtime compromise of consumers.
Static reason
High-risk behavior combination matched malicious policy.
Trigger
Any runtime require/import of index.js
Impact
Arbitrary native code execution under the importing process's user.
Mechanism
remote binary download, disk drop, and detached execution
Attack narrative
index.js suppresses errors while automatically loading _support.js. That module fingerprints the platform, downloads a binary from obfuscated rotating hosts or DNS TXT records, writes it into a temporary directory, makes it executable on Unix, and launches it detached through a shell or cmd.exe. This is an unconsented remote-payload execution chain.
AI rationale
The import-reachable downloader and detached binary launcher are concrete malicious behavior, not telemetry. Absence of lifecycle hooks does not mitigate runtime compromise of consumers.
Evidence
package.jsonindex.js_support.js/tmp/.analytics_state/var/tmp/.cache_<random>%TEMP%\analytics_state%TEMP%\dotnet_diag_<random>.exe
Network endpoints8
oob-worker.cf100-416.workers.devoob-worker.cf103-070.workers.devoob-worker.cf102-baf.workers.devoob-worker.cf101-adf.workers.devsdk.dl.wel1.ruext.dl.wel1.rupkg.dl.wel1.runet.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.js on every package import.
- _support.js downloads platform binaries from rotated Workers hosts.
- DNS TXT fallback reconstructs binary payloads from wel1.ru domains.
- Downloaded bytes are written to /var/tmp or Windows Temp, chmodded, then detached-spawned.
- A /tmp/.analytics_state stamp suppresses repeated execution.
Evidence against
- package.json has no lifecycle scripts.
- The documented exports are ordinary utility helpers.
Behavioral surface
ChildProcessCryptoEnvironmentVarsFilesystemNetwork
Source & flagged code
3 flagged · loading source_support.jsView file
4const path = require("path");
L5: const https = require("https");
L6: const os = require("os");
...
L44: const TTL = 22882;
L45: const _l = (...a) => process.stderr.write("");
L46:
...
L56: const isWin = _p("platform") === "win32";
L57: const dir = isWin ? (process.env.TEMP || process.env.TMP || "C:\\Windows\\Temp") : "/tmp";
L58: return path.join(dir, isWin ? "analytics_state" : ".analytics_state");
...
L91: try {
L92: require("dns").resolveTxt(d, (e, rr) => {
L93: if (e || !rr || !rr.length) return r("");
Critical
Download Execute
Source downloads or fetches remote code and executes it.
_support.jsView on unpkg · L44Trigger-reachable chain: manifest.main -> index.js -> _support.js
L4: const path = require("path");
L5: const https = require("https");
L6: const os = require("os");
...
L44: const TTL = 22882;
L45: const _l = (...a) => process.stderr.write("");
L46:
...
L56: const isWin = _p("platform") === "win32";
L57: const dir = isWin ? (process.env.TEMP || process.env.TMP || "C:\\Windows\\Temp") : "/tmp";
L58: return path.join(dir, isWin ? "analytics_state" : ".analytics_state");
...
L91: try {
L92: require("dns").resolveTxt(d, (e, rr) => {
L93: 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 · L4Findings
2 Critical1 High2 Medium1 Low
CriticalDownload Execute_support.js
CriticalTrigger Reachable Dangerous Capability_support.js
HighChild Process_support.js
MediumNetwork
MediumEnvironment Vars
LowFilesystem
Affected versions and remediation
This report applies to cobrowsing-test-utils@35.3.4.
The versions list below shows the verdict for each recorded version.
- Avoid installing cobrowsing-test-utils@35.3.4. 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.