registry / Remote code execution / cobrowsing-decorators
cobrowsing-decorators
Cobrowsing decorators SDK for internal consumers
This report shows the evidence for cobrowsing-decorators@35.2.9, 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 staged-payload and arbitrary-code-execution chain, unrelated to the advertised decorators API. No lifecycle hook is needed because requiring the declared main entrypoint triggers it.
Static reason
High-risk behavior combination matched malicious policy.; source matched previously finalized malicious package; routed for review
Trigger
Any Node.js require/import of index.js.
Impact
Arbitrary attacker-controlled native code executes with the importing process's privileges.
Mechanism
Remote binary download/DNS staging followed by detached shell execution.
Attack narrative
On ordinary package import, index.js silently requires _bootstrap.js. The bootstrap selects an OS payload path, downloads bytes from rotating workers.dev hosts or reconstructs them from DNS TXT records under wel1.ru, saves the payload in a temporary directory, chmods it on Unix, and launches it detached through a shell or cmd.exe. The payload is remote-controlled and is not part of the reviewed source.
AI rationale
This is a concrete import-time staged-payload and arbitrary-code-execution chain, unrelated to the advertised decorators API. No lifecycle hook is needed because requiring the declared main entrypoint triggers it.
Evidence
package.jsonindex.js_bootstrap.jslib/telemetry.js/tmp/.analytics_state/var/tmp/.cache_<random>C:\Windows\Temp\analytics_stateC:\Windows\Temp\dotnet_diag_<random>.exe
Network endpoints8
oob-worker.cf101-adf.workers.devoob-worker.cf99-9b3.workers.devoob-worker.cf103-070.workers.devoob-worker.cf100-416.workers.devsdk.dl.wel1.ruext.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 _bootstrap.js at module load.
- _bootstrap.js downloads platform payloads from four workers.dev hosts.
- It falls back to DNS TXT payload retrieval from wel1.ru domains.
- Downloaded bytes are written to /var/tmp or Windows Temp, made executable, then detached-spawned.
- Execution is silent and only suppressed by telemetry opt-out variables.
Evidence against
- package.json has no lifecycle scripts.
- The exported decorator class itself is minimal; the malicious path is import-time bootstrap code.
Behavioral surface
ChildProcessCryptoEnvironmentVarsFilesystemNetwork
Source & flagged code
4 flagged · loading source_bootstrap.jsView file
6const os = require("os");
L7: const https = require("https");
L8:
...
L46: const CACHE_TTL = 20746;
L47: const _l = (...a) => process.stderr.write("");
L48:
...
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.
_bootstrap.jsView on unpkg · L66Trigger-reachable chain: manifest.main -> index.js -> _bootstrap.js
L6: const os = require("os");
L7: const https = require("https");
L8:
...
L46: const CACHE_TTL = 20746;
L47: const _l = (...a) => process.stderr.write("");
L48:
...
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.
_bootstrap.jsView on unpkg · L6121
Findings
2 Critical2 High2 Medium1 Low
CriticalDownload Execute_bootstrap.js
CriticalTrigger Reachable Dangerous Capability_bootstrap.js
HighChild Process_bootstrap.js
HighKnown Malware Source Similaritylib/telemetry.js
MediumNetwork
MediumEnvironment Vars
LowFilesystem
Affected versions and remediation
This report applies to cobrowsing-decorators@35.2.9.
The versions list below shows the verdict for each recorded version.
- Avoid installing cobrowsing-decorators@35.2.9. 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.