CVE-2021-43571: Starkbank ecdsa Improper Verification Of Cryptographic Signature Vulnerability

CRITICAL
Advisory Identifier: GHSA-q9q6-f556-gpm7
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CVSS 9.8
CWE-347
Published
Advisory Summary

CVE-2021-43571 is a CRITICAL (CVSS 9.8) improper verification of cryptographic signature vulnerability (CWE-347: Improper Verification of Cryptographic Signature) affecting Starkbank ecdsa libraries in the npm ecosystem. The issue involves improper verification of cryptographic signature in starkbank-ecdsa. Remediation is available by upgrading affected packages to version 1.1.3.

CVE-2021-43571 at a Glance

CVE Identifier CVE-2021-43571
GHSA Identifier GHSA-q9q6-f556-gpm7
Severity CRITICAL
CVSS v3.1 Base Score 9.8
CWE Classification CWE-347: Improper Verification of Cryptographic Signature
Affected Product Starkbank ecdsa
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 9.8

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2021-43571

To remediate this vulnerability, upgrade all affected Starkbank ecdsa dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

starkbank-ecdsa fixed: 1.1.3 
npm install starkbank-ecdsa@1.1.3
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

npm ls starkbank-ecdsa

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2021-43571, inspect your project dependencies using npm:

npm ls starkbank-ecdsa

Analyze the terminal output to locate any version of Starkbank ecdsa in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.1.3), your application is affected.

Note: The npm ls starkbank-ecdsa command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-347: Improper Verification of Cryptographic Signature, where the product does not verify, or incorrectly verifies, the cryptographic signature for data. In Starkbank ecdsa, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

The verify function in the Stark Bank Node.js ECDSA library (ecdsa-node) 1.1.2 fails to check that the signature is non-zero, which allows attackers to forge signatures on arbitrary messages.

CVE-2021-43571 Affected Starkbank ecdsa Versions

1 component(s)
Fixed Versions:
1.1.3
Product / Package Ecosystem Affected Versions Fixed Version
starkbank-ecdsa
npm/starkbank-ecdsa
npm
< 1.1.3
1.1.3

References

NVD — CVE-2021-43571 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-43571
Starkbank ecdsa Source Repository REPOSITORY
https://github.com/starkbank/ecdsa-node
Starkbank ecdsa Release RELEASE
https://github.com/starkbank/ecdsa-node/releases/tag/v1.1.3
research.nccgroup.com/2021/11/08/technica... WEB
https://research.nccgroup.com/2021/11/08/technical-advisory-arbitrary-signature-forgery-in-stark-bank-ecdsa-libraries

Frequently Asked Questions

What is CVE-2021-43571?
CVE-2021-43571 is a security vulnerability in Starkbank ecdsa involving Improper Verification of Cryptographic Signature in starkbank-ecdsa under CWE-347: Improper Verification of Cryptographic Signature.
Which Starkbank ecdsa versions are affected?
Affected versions include releases prior to 1.1.3 across affected packages: starkbank-ecdsa.
What version fixes CVE-2021-43571?
Upgrading to 1.1.3 (or the latest patched release for your respective branch) resolves the vulnerability.
Is starkbank-ecdsa affected?
Yes, starkbank-ecdsa is affected in releases prior to 1.1.3. Upgrade your dependency to 1.1.3 or later.
What is the CVSS score of CVE-2021-43571?
CVE-2021-43571 has a CVSS v3.1 base score of 9.8 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2021-43571?
CVE-2021-43571 is classified under CWE-347: Improper Verification of Cryptographic Signature (The product does not verify, or incorrectly verifies, the cryptographic signature for data.).
How can I check npm dependencies for CVE-2021-43571?
Run the dependency tree command: 'npm ls starkbank-ecdsa'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-q9q6-f556-gpm7",
  "modified" : "2021-11-15T14:44:13Z",
  "published" : "2021-11-10T20:58:42Z",
  "aliases" : [ "CVE-2021-43571" ],
  "summary" : "Improper Verification of Cryptographic Signature in starkbank-ecdsa",
  "details" : "The verify function in the Stark Bank Node.js ECDSA library (ecdsa-node) 1.1.2 fails to check that the signature is non-zero, which allows attackers to forge signatures on arbitrary messages.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "starkbank-ecdsa"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.1.3"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-43571"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/starkbank/ecdsa-node"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/starkbank/ecdsa-node/releases/tag/v1.1.3"
  }, {
    "type" : "WEB",
    "url" : "https://research.nccgroup.com/2021/11/08/technical-advisory-arbitrary-signature-forgery-in-stark-bank-ecdsa-libraries"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-347" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-11-10T18:27:14Z",
    "nvd_published_at" : "2021-11-09T22:15:00Z"
  }
}