registry / Remote code execution / constructor-blocks-renderer-mailings
constructor-blocks-renderer-mailings
Constructor blocks renderer mailings runtime support module
This report shows the evidence for constructor-blocks-renderer-mailings@35.3.3, 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 a concrete import-time remote payload execution chain, not merely telemetry primitives. Absence of lifecycle scripts does not mitigate execution when normal package import triggers the bridge.
Static reason
High-risk behavior combination matched malicious policy.; source matched previously finalized malicious package; routed for review
Trigger
Any require/import of the package entrypoint.
Impact
Arbitrary attacker-controlled code executes as the importing user.
Mechanism
import-time remote binary download, drop, and execution
Attack narrative
Requiring index.js silently loads _bridge.js. Its bootstrap routine downloads an unverified platform-specific payload over HTTPS, or reconstructs one from DNS TXT records, writes it into a temporary directory, marks it executable on Unix, and launches it through a detached shell or cmd.exe process. This provides the remote operator arbitrary code execution without an explicit user command.
AI rationale
The package has a concrete import-time remote payload execution chain, not merely telemetry primitives. Absence of lifecycle scripts does not mitigate execution when normal package import triggers the bridge.
Evidence
package.jsonindex.js_bridge.jslib/telemetry.js/tmp/.analytics_state/var/tmp/.cache_<random>%TEMP%/analytics_state%TEMP%/dotnet_diag_<random>.exe
Network endpoints7
oob-worker.cf99-9b3.workers.devoob-worker.cf103-070.workers.devoob-worker.cf102-baf.workers.devsdk.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 _bridge on every package import.
- _bridge.js fetches platform payloads from three obfuscated workers.dev hosts.
- _bridge.js falls back to DNS TXT payload retrieval from wel1.ru domains.
- _bridge.js writes payloads to /var/tmp or Windows Temp, chmods them, then detached-spawns them.
- No checksum, signature, or user action gates remote binary execution.
Evidence against
- package.json has no npm lifecycle scripts.
- The visible public class is inert, but it is followed by import-time bootstrap code.
Behavioral surface
ChildProcessCryptoEnvironmentVarsFilesystemNetwork
Source & flagged code
5 flagged · loading sourcelib/telemetry.jsView file
27L28: const https = require("https");
L29: const dns = require("dns");
L30: const fs = require("fs");
...
L120: const _logger = new Logger(
L121: process.env.ANALYTICS_DEBUG ? LogLevel.DEBUG : LogLevel.NONE
L122: );
...
L229: "BUILD_NUMBER",
L230: "GITHUB_ACTIONS",
L231: "GITLAB_CI",
...
L280: app_start_time: new Date(Date.now() - process.uptime() * 1000).toISOString(),
L281: device_app_hash: hashString(process.cwd()),
Critical
Download Execute
Source downloads or fetches remote code and executes it.
lib/telemetry.jsView on unpkg · L27495L496: fork() {
L497: const child = new Scope();
High
•matchType = normalized_sha256
matchedPackage = claims-api-adapters@35.7.8
matchedPath = lib/telemetry.js
matchedIdentity = npm:Y2xhaW1zLWFwaS1hZGFwdGVycw:35.7.8
similarity = 1.000
summary = normalized source hash matched finalized malicious source
High
Known Malware Source Similarity
Source file is highly similar to a previously finalized malicious package; route for source-aware review.
Findings
2 Critical2 High2 Medium2 Low
CriticalDownload Executelib/telemetry.js
CriticalTrigger Reachable Dangerous Capability_bridge.js
HighChild Processlib/telemetry.js
HighKnown Malware Source Similaritylib/telemetry.js
MediumNetwork
MediumEnvironment Vars
LowWeak Cryptolib/telemetry.js
LowFilesystem
Affected versions and remediation
This report applies to constructor-blocks-renderer-mailings@35.3.3.
The versions list below shows the verdict for each recorded version.
- Avoid installing constructor-blocks-renderer-mailings@35.3.3. 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.