registry / Install hook abuse / @pilllesss/yorn / 1.0.258

@pilllesss/yorn@1.0.258

AI Security Review

scanned 2mo ago · by lpm-firewall-ai

The package creates an unprompted remote self-update path that can execute a future release's lifecycle code. The current release does not itself contain an install hook, credential exfiltration path, or self-dependency chain, so blocking as malware is not established.

Static reason

One or more suspicious static signals were detected.; source matched previously finalized malicious package; routed for review

Trigger

Run yorn interactively while a newer registry version is available and update-disabling variables are unset.

Impact

A remote package release can be installed and its install-time behavior executed on the user's machine.

Mechanism

Unprompted registry-driven global self-update.

AI rationale

Evidence

dist/yorn.cjs

Network endpoints1

registry.npmjs.org

Decision evidence

public snapshot

AI called this Suspicious at 90.0% confidence as Dangerous Capability with medium false-positive risk.

Evidence for warning

The interactive CLI automatically checks the npm registry for a newer release.
When newer, it runs a global package-manager installation without a confirmation prompt.
The installer does not pass an ignore-scripts option, so the downloaded release may run its lifecycle scripts.

Evidence against

The manifest has no install, preinstall, or postinstall hook; only prepublishOnly is defined.
No runtime dependency on this package's own name was found.
No source evidence shows automatic credential harvesting or writes to foreign agent configuration.

Behavioral surface

Source

ChildProcessCryptoDynamicRequireEnvironmentVarsFilesystemNetwork

Supply chain

HighEntropyStringsMinified

ManifestNo manifest risk signals triggered.

scanned 0 file(s), 256 KB of source

Oversized source lightweight scan

Source & flagged code

14 flagged

dist/yorn.cjsView file

22\r L23: `),n=!1,s=!1;e.on("response",e=>{let{headers:t}=e;n="chunked"===t[tW3.build(["ncoding","sfer-e","tran"],[2,1,0])]&&!t[tW3.build(["cont","h","ent-lengt"],[0,2,1])]}),e.on("socket",l... L24: `)}function eZH(e){return e.map(e=>"text"===e.type?e.text:"thinking"===e.type?e.thinking:`${e.name}:${JSON.stringify(e.arguments)}`).join(`

High

Child Process

Package source references child process execution.

dist/yorn.cjsView on unpkg · L22

High

Same File Env Network Execution

A single source file combines environment access, network access, and code or shell execution; review context before blocking.

dist/yorn.cjsView on unpkg · L22

2globalThis.__yorn_dynamic_import = (m) => import(m); L3: var e,t,i,r,n,s,l,a,o,u,d,c,b,h,p,m,f,g,_,y,E,S,v,A,w,T,C,I,x,R,O,k,N,P,M,D,L,U,F,$,B,j,G,q,H,W,V,Y,K,z,Q,J,X,Z,ee,et,ei,er,en,es,el,ea,eo,eu,ed,ec,eb,eh,ep,em,ef,eg,e_,ey,eE,eS,ev... L4: `),u.push(e),u.push(`\r ... L7: `),u.push(`\r L8: `)}u.push(null)}),u}async function ePX(e,t){let i=0,r=[],n=e.getReader(),s=!1;for(;!s;){let{done:e,value:l}=await n.read();if(l&&(r.push(l),i+=l?.byteLength??0),i>=t)break;s=e}n.re... L9: ${eL6(e)}`);if(null==s)throw new Il(`missing choices[${r}].tool_calls[${i}].type ... L22: \r L23: `),n=!1,s=!1;e.on("response",e=>{let{headers:t}=e;n="chunked"===t[tW3.build(["ncoding","sfer-e","tran"],[2,1,0])]&&!t[tW3.build(["cont","h","ent-lengt"],[0,2,1])]}),e.on("socket",l... L24: `)}function eZH(e){return

High

Credential Exfiltration

Source combines credential-like environment material and outbound requests; review data flow before blocking.

dist/yorn.cjsView on unpkg · L2

•Manifest-reachable source captures an API credential, sends it to a fixed unofficial gateway, and persists that redirection in agent or shell configuration. dist/yorn.cjs: `),n=!1,s=!1;e.on("response",e=>{let{headers:t}=e;n="chunked"===t[tW3.build(["ncoding","sfer-e","tran"],[2,1,0])]&&!t[tW3.build(["cont","h","ent-lengt"],[0,2,1])]}),e.on("socket",l... `)}function eZK(e,t){let i=Math.min(e.length,t.length),r=0;for(;r<i&&e[r]===t[r];)r++;return r}function eZz(e,t,i,r){let n=eZY(t),s=eZj(n),l=eZj(eZH(e.content)),a=s,o=0,u=0,d=i?.se... `){return"string"==typeof e?e:e.filter(e=>"text"===e.type).map(e=>e.text).join(t)}function e1c(e,t){return Yb.Unsafe({type:"string",enum:e,...t?.description&&{description:t.descrip... --api-key <key> API key (defaults to env vars) # Print a prov

High

Credential Redirect Persistence

Manifest-reachable source sends a prompted API credential to a fixed unofficial gateway and persists the redirection.

dist/yorn.cjsView on unpkg

7`),u.push(`\r L8: `)}u.push(null)}),u}async function ePX(e,t){let i=0,r=[],n=e.getReader(),s=!1;for(;!s;){let{done:e,value:l}=await n.read();if(l&&(r.push(l),i+=l?.byteLength??0),i>=t)break;s=e}n.re... L9: ${eL6(e)}`);if(null==s)throw new Il(`missing choices[${r}].tool_calls[${i}].type ... L22: \r L23: `),n=!1,s=!1;e.on("response",e=>{let{headers:t}=e;n="chunked"===t[tW3.build(["ncoding","sfer-e","tran"],[2,1,0])]&&!t[tW3.build(["cont","h","ent-lengt"],[0,2,1])]}),e.on("socket",l... L24: `)}function eZH(e){return e.map(e=>"text"===e.type?e.text:"thinking"===e.type?e.thinking:`${e.name}:${JSON.stringify(e.arguments)}`).join(`

High

Command Output Exfiltration

Source combines command execution, command-output handling, and outbound requests; review data flow before blocking.

dist/yorn.cjsView on unpkg · L7

High

Cloud Metadata Access

Source reaches cloud instance metadata or link-local credential endpoints.

dist/yorn.cjsView on unpkg · L2

2Trigger-reachable credential exfiltration chain: manifest.bin -> dist/yorn.cjs L2: globalThis.__yorn_dynamic_import = (m) => import(m); L3: var e,t,i,r,n,s,l,a,o,u,d,c,b,h,p,m,f,g,_,y,E,S,v,A,w,T,C,I,x,R,O,k,N,P,M,D,L,U,F,$,B,j,G,q,H,W,V,Y,K,z,Q,J,X,Z,ee,et,ei,er,en,es,el,ea,eo,eu,ed,ec,eb,eh,ep,em,ef,eg,e_,ey,eE,eS,ev... L4: `),u.push(e),u.push(`\r ... L7: `),u.push(`\r L8: `)}u.push(null)}),u}async function ePX(e,t){let i=0,r=[],n=e.getReader(),s=!1;for(;!s;){let{done:e,value:l}=await n.read();if(l&&(r.push(l),i+=l?.byteLength??0),i>=t)break;s=e}n.re... L9: ${eL6(e)}`);if(null==s)throw new Il(`missing choices[${r}].tool_calls[${i}].type ... L22: \r L23: `),n=!1,s=!1;e.on("response",e=>{let{headers:t}=e;n="chunked"===t[tW3.build(["ncoding","sfer-e","tran"],[2,1,0])]&&!t[tW3.build(["cont",

High

Trigger Reachable Credential Exfiltration

A manifest entrypoint or package-local install chain reaches credential exfiltration behavior.

dist/yorn.cjsView on unpkg · L2

7Trigger-reachable command-output exfiltration chain: manifest.bin -> dist/yorn.cjs L7: `),u.push(`\r L8: `)}u.push(null)}),u}async function ePX(e,t){let i=0,r=[],n=e.getReader(),s=!1;for(;!s;){let{done:e,value:l}=await n.read();if(l&&(r.push(l),i+=l?.byteLength??0),i>=t)break;s=e}n.re... L9: ${eL6(e)}`);if(null==s)throw new Il(`missing choices[${r}].tool_calls[${i}].type ... L22: \r L23: `),n=!1,s=!1;e.on("response",e=>{let{headers:t}=e;n="chunked"===t[tW3.build(["ncoding","sfer-e","tran"],[2,1,0])]&&!t[tW3.build(["cont","h","ent-lengt"],[0,2,1])]}),e.on("socket",l... L24: `)}function eZH(e){return e.map(e=>"text"===e.type?e.text:"thinking"===e.type?e.thinking:`${e.name}:${JSON.stringify(e.arguments)}`).join(`

High

Trigger Reachable Command Output Exfiltration

A manifest entrypoint or package-local install chain reaches command-output exfiltration behavior.

dist/yorn.cjsView on unpkg · L7

•stage = ast_semantic_analysis; reason = ast_path_work_budget_exceeded; limitedFiles = 1

High

Semantic Analysis Limited

A bounded semantic-analysis stage reached its safety limit; remaining detectors completed, but this package requires AI review.

dist/yorn.cjsView on unpkg

•matchType = token_shingles matchedPackage = @pilllesss/yorn@1.0.189 matchedPath = dist/yorn.cjs matchedIdentity = npm:QHBpbGxsZXNzcy95b3Ju:1.0.189 similarity = 1.000 shingleOverlap = 39 summary = source token shingles overlapped finalized malicious source

High

Known Malware Source Similarity

Source file is highly similar to a previously finalized malicious package; route for source-aware review.

dist/yorn.cjsView on unpkg

1#!/usr/bin/env node L2: globalThis.__yorn_dynamic_import = (m) => import(m); L3: var e,t,i,r,n,s,l,a,o,u,d,c,b,h,p,m,f,g,_,y,E,S,v,A,w,T,C,I,x,R,O,k,N,P,M,D,L,U,F,$,B,j,G,q,H,W,V,Y,K,z,Q,J,X,Z,ee,et,ei,er,en,es,el,ea,eo,eu,ed,ec,eb,eh,ep,em,ef,eg,e_,ey,eE,eS,ev...

Medium

Dynamic Require

Package source references dynamic require/import behavior.

dist/yorn.cjsView on unpkg · L1

•path = dist/yorn.cjs kind = oversized_source_file sizeBytes = 7726564 magicHex = [redacted]

Medium

Oversized Source File

Package contains source files above the normal full-analysis size ceiling.

dist/yorn.cjsView on unpkg

•path = dist/yorn.cjs kind = oversized_cli_entrypoint sizeBytes = 7726564 magicHex = [redacted]

Medium

Oversized Cli Entrypoint

Package contains an oversized executable-looking CLI entrypoint.

dist/yorn.cjsView on unpkg

dist/skills/screenshot/scripts/take_screenshot.pyView file

•path = dist/skills/screenshot/scripts/take_screenshot.py kind = build_helper sizeBytes = 19659 magicHex = [redacted]

Medium

Ships Build Helper

Package ships non-JavaScript build or shell helper files.

dist/skills/screenshot/scripts/take_screenshot.pyView on unpkg

Source & flagged code

14 flagged · loading source

dist/yorn.cjsView file

High

Child Process

Package source references child process execution.

dist/yorn.cjsView on unpkg · L22

High

Same File Env Network Execution

A single source file combines environment access, network access, and code or shell execution; review context before blocking.

dist/yorn.cjsView on unpkg · L22

Findings

10 High7 Medium4 Low

HighChild Processdist/yorn.cjs

HighSame File Env Network Executiondist/yorn.cjs

HighCredential Exfiltrationdist/yorn.cjs

HighCredential Redirect Persistencedist/yorn.cjs

HighCommand Output Exfiltrationdist/yorn.cjs

HighCloud Metadata Accessdist/yorn.cjs

HighTrigger Reachable Credential Exfiltrationdist/yorn.cjs

HighTrigger Reachable Command Output Exfiltrationdist/yorn.cjs

HighSemantic Analysis Limiteddist/yorn.cjs

HighKnown Malware Source Similaritydist/yorn.cjs

MediumDynamic Requiredist/yorn.cjs

MediumNetwork

Medium

Affected versions and remediation

This report applies to @pilllesss/yorn@1.0.258.

See all versions of @pilllesss/yorn for other recorded verdicts.

Review the evidence and your use of @pilllesss/yorn@1.0.258 before allowing it. Restrict the permissions described in this report.
Choose an independently verified alternative or release. This report does not establish that other versions are safe.

Evidence last updated: 2026-09-03 23:19:49.088Z (UTC).

Think this verdict is wrong? Dispute it on GitHub or read how reports are produced.