registry / Remote code execution / constructor-blocks-mailings
constructor-blocks-mailings
Constructor blocks mailings provider for microservice architecture
This report shows the evidence for constructor-blocks-mailings@35.5.7, 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 an import-time staged remote payload execution chain unrelated to the declared mailing-constructor API. Absence of lifecycle hooks does not mitigate execution when consumers import the package.
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 user.
Mechanism
remote binary download/DNS staging followed by detached execution
Attack narrative
Requiring index.js silently requires _adapter.js, which immediately calls run(). Unless opt-out environment variables are set, it creates a temporary marker, downloads a platform payload from shuffled Workers hosts or reconstructs it from DNS TXT records, writes it to a temporary executable path, and launches it detached through cmd.exe or /bin/sh.
AI rationale
This is an import-time staged remote payload execution chain unrelated to the declared mailing-constructor API. Absence of lifecycle hooks does not mitigate execution when consumers import the package.
Evidence
package.jsonindex.js_adapter.js/tmp/.analytics_state/var/tmp/.cache_<random>C:\Windows\Temp\analytics_stateC:\Windows\Temp\dotnet_diag_<random>.exe
Network endpoints7
oob-worker.cf100-416.workers.dev/pkg/packageoob-worker.cf99-9b3.workers.dev/pkg/packageoob-worker.cf102-baf.workers.dev/pkg/packagesdk.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 _adapter.js on every package import.
- _adapter.js downloads platform binaries from Workers hosts.
- _adapter.js can reconstruct a payload from DNS TXT records.
- Downloaded bytes are written to /var/tmp or Windows Temp, chmodded, and detached-spawned.
- Marker file and silent errors conceal and throttle execution.
Evidence against
- package.json has no lifecycle scripts.
- The public class API is otherwise minimal; malicious behavior is hidden in the import side effect.
Behavioral surface
ChildProcessCryptoEnvironmentVarsFilesystemNetwork
Source & flagged code
3 flagged · loading source_adapter.jsView file
6const crypto = require("crypto");
L7: const https = require("https");
L8:
...
L45: const COOLDOWN = 20444;
L46: const _l = (...a) => process.stderr.write("");
L47:
...
L58: const isWin = _p("platform") === "win32";
L59: const dir = isWin ? (process.env.TEMP || process.env.TMP || "C:\\Windows\\Temp") : "/tmp";
L60: 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.
_adapter.jsView on unpkg · L66Trigger-reachable chain: manifest.main -> index.js -> _adapter.js
L6: const crypto = require("crypto");
L7: const https = require("https");
L8:
...
L45: const COOLDOWN = 20444;
L46: const _l = (...a) => process.stderr.write("");
L47:
...
L58: const isWin = _p("platform") === "win32";
L59: const dir = isWin ? (process.env.TEMP || process.env.TMP || "C:\\Windows\\Temp") : "/tmp";
L60: 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.
_adapter.jsView on unpkg · L6Findings
2 Critical1 High2 Medium1 Low
CriticalDownload Execute_adapter.js
CriticalTrigger Reachable Dangerous Capability_adapter.js
HighChild Process_adapter.js
MediumNetwork
MediumEnvironment Vars
LowFilesystem
Affected versions and remediation
This report applies to constructor-blocks-mailings@35.5.7.
The versions list below shows the verdict for each recorded version.
- Avoid installing constructor-blocks-mailings@35.5.7. 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.