registry / AI-agent capability abuse / @pilllesss/yorn / 1.0.270

@pilllesss/yorn@1.0.270

AI Security Review

scanned 2mo ago · by lpm-firewall-ai

This is not a proven install-time malware chain, but it embeds a largely undocumented and obfuscated OAuth-backed coding-agent provider with broad command and data access. The unresolved credential and workspace-data exposure warrants a warning rather than publication as clean.

Static reason

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

Trigger

A user runs yorn, selects or logs into the hidden Antigravity provider, or allows the coding agent to execute a command.

Impact

A user’s OAuth credential, workspace context, and command output may be available to the selected remote provider; the opaque implementation prevents confidently limiting that exposure.

Mechanism

OAuth token persistence and remote AI-agent request forwarding

AI rationale

Evidence

dist/yorn.cjsREADME.md~/.yorn/agent/auth.json~/.yorn/agent/settings.json

Network endpoints5

accounts.google.com/o/oauth2/v2/authoauth2.googleapis.com/tokendaily-cloudcode-pa.googleapis.comdaily-cloudcode-pa.sandbox.googleapis.comcloudcode-pa.googleapis.com

Decision evidence

public snapshot

AI called this Suspicious at 86.0% confidence as Dangerous Capability with medium false-positive risk.

Evidence for warning

The executable bundle contains a hidden Antigravity OAuth provider that handles access and refresh tokens and sends coding-agent requests to Google Cloud endpoints.
The published artifact is an unusually large, heavily string-obfuscated CLI bundle, making its network and credential behavior difficult to audit.
The package persists provider API keys and OAuth tokens in the user’s home configuration directory.
The CLI is designed to run shell commands and can send agent context and command results to a selected remote model provider.

Evidence against

package.json has no preinstall, install, or postinstall hook.
The executable is exposed as a user-invoked yorn command rather than an automatic install-time entrypoint.
The inspected Antigravity OAuth flow uses Google account and Google API endpoints rather than a confirmed attacker-controlled host.
The screenshot helpers are explicit tools that request permission or write a user-selected screenshot file.

Behavioral surface

Source

ChildProcessCrypto

Source & flagged code

13 flagged

dist/yorn.cjsView file

22\r L23: `),n=!1,s=!1;e.on("response",e=>{let{headers:t}=e;n="chunked"===t[tzS.build(["ncodin","transfer-e","g"],[1,0,2])]&&!t[tzS.build(["t-length","conten"],[1,0])]}),e.on("socket",l=>{le... L24: `)}function e0B(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

11${eU0(e)}`);if(null==o)throw new Il(`missing choices[${r}].tool_calls[${i}].function.arguments L12: ${eU0(e)}`);return{...a,id:l,type:s,function:{...d,name:u,arguments:o}}})}}:{...s,message:{...u,content:l,role:d,refusal:t.refusal??null},finish_reason:i,index:r,logprobs:n}}),crea... L13: Content-Disposition: form-data; name="`;return e.forEach((e,t)=>"string"==typeof e?r.push(n+My(t)+`"\r ... L22: \r L23: `),n=!1,s=!1;e.on("response",e=>{let{headers:t}=e;n="chunked"===t[tzS.build(["ncodin","transfer-e","g"],[1,0,2])]&&!t[tzS.build(["t-length","conten"],[1,0])]}),e.on("socket",l=>{le... L24: `)}function e0B(e){return e.map(e=>"text"===e.type?e.text:"thinking"===e.type?e.thinking:`${e.name}:${JSON.stringify(e.arguments)}`).join(`

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 · L11

•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[tzS.build(["ncodin","transfer-e","g"],[1,0,2])]&&!t[tzS.build(["t-length","conten"],[1,0])]}),e.on("socket",l=>{le... `)}function e0q(e,t){let i=Math.min(e.length,t.length),r=0;for(;r<i&&e[r]===t[r];)r++;return r}function e0H(e,t,i,r){let n=e0G(t),s=e0L(n),l=e0L(e0B(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 e2l(e,t){return Kh.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 eDK(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: ${eU0(e)}`);if(null==s)throw new Il(`missing choices[${r}].tool_calls[${i}].type ... L11: ${eU0(e)}`);if(null==o)throw new Il(`missing choices[${r}].tool_calls[${i}].function.arguments L12: ${eU0(e)}`);return{...a,id:l,type:s,function:{...d,name:u,arguments:o}}})}}:{...s,message:{...u,content:l,role:d,refusal:t.refusal??null},finish_reason:i,index:r,logprobs:n}}),crea... L13: Content-Disposition: form-data; name="`;return e.forEach((e,t)=>"string"==typeof e?r.push(n+My(t)+`"\r ... L22: \r L23: `),n=!1,s=!1;e.on("response",e=>{let{headers:t}=e;n="chunked"===t[tzS.build(["ncodin","tran

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

2globalThis.__yorn_dynamic_import = (m) => import(m); L3: var e,t,i,r,n,s,l,a,o,u,d,c,h,b,p,m,f,g,_,y,E,S,v,A,w,T,C,I,x,R,O,k,N,P,M,D,L,F,U,B,$,j,G,q,H,W,V,K,Y,z,Q,J,X,Z,ee,et,ei,er,en,es,el,ea,eo,eu,ed,ec,eh,eb,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 eDK(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: ${eU0(e)}`);if(null==s)throw new Il(`missing choices[${r}].tool_calls[${i}].type ... L11: ${eU0(e)}`);if(null==o)throw new Il(`missing choices[${r}].tool_calls[${i}].function.arguments L12: ${eU0(e)}`);return{...a,id:l,type:s,function:{...d,name:u,arguments:o}}})}}:{...s,message:{...u,content:l,role:d,refusal:t.

High

Cloud Metadata Access

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

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 eDK(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: ${eU0(e)}`);if(null==s)throw new Il(`missing choices[${r}].tool_calls[${i}].type ... L11: ${eU0(e)}`);if(null==o)throw new Il(`missing choices[${r}].tool_calls[${i}].function.arguments L12: ${eU0(e)}`);return{...a,id:l,type:s,function:{...d,name:u,arguments:o}}})}}:{...s,message:{...u,content:l,role:d,refusal:t.refusal??null},finish_reason:i,index:r,logprobs:n}}),crea... L13: Content-Disposition: form-data; name="`;return e.forEach((e,t)=>"string"==typeof e?r.push(n+My(t)+`"\r ... L22: \r L23: `),n=!1,

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 = normalized_sha256 matchedPackage = @pilllesss/yorn@1.0.262 matchedPath = dist/yorn.cjs matchedIdentity = npm:QHBpbGxsZXNzcy95b3Ju:1.0.262 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.

dist/yorn.cjsView on unpkg

•matchType = malicious_source_fingerprint_signature signature = f5544ecd80b66e25 signatureType = suspicious_hashes sourceLabel = final_verdict:malicious matchedPackage = @pilllesss/yorn@1.0.262 matchedPath = dist/yorn.cjs matchedIdentity = npm:QHBpbGxsZXNzcy95b3Ju:1.0.262 similarity = 1.000 shingleOverlap = 3 summary = package final verdict is malicious

High

Known Malware Source Fingerprint Signature

Source fingerprint signature matches a known malicious package signature; 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,h,b,p,m,f,g,_,y,E,S,v,A,w,T,C,I,x,R,O,k,N,P,M,D,L,F,U,B,$,j,G,q,H,W,V,K,Y,z,Q,J,X,Z,ee,et,ei,er,en,es,el,ea,eo,eu,ed,ec,eh,eb,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 = 8070330 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 = 8070330 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

13 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 · L11

Findings

9 High7 Medium4 Low

HighChild Processdist/yorn.cjs

HighSame File Env Network Executiondist/yorn.cjs

HighCredential Redirect Persistencedist/yorn.cjs

HighCommand Output Exfiltrationdist/yorn.cjs

HighCloud Metadata Accessdist/yorn.cjs

HighTrigger Reachable Command Output Exfiltrationdist/yorn.cjs

HighSemantic Analysis Limiteddist/yorn.cjs

HighKnown Malware Source Similaritydist/yorn.cjs

HighKnown Malware Source Fingerprint Signaturedist/yorn.cjs

MediumDynamic Requiredist/yorn.cjs

MediumNetwork

MediumEnvironment Vars

MediumShips Build Helper

Affected versions and remediation

This report applies to @pilllesss/yorn@1.0.270.

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

Review the evidence and your use of @pilllesss/yorn@1.0.270 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: 2026-09-05 01:00:10.286Z (UTC).

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