Rule Definition
Many web applications and APIs do not properly protect sensitive data, such as financial, healthcare, and PII. Attackers may steal or modify such weakly protected data to conduct credit card fraud, identity theft, or other crimes. Sensitive data may be compromised without extra protection, such as encryption at rest or in transit, and requires special precautions when exchanged with the browser. The use of a non-standard algorithm is dangerous because a determined attacker may be able to break the algorithm and compromise whatever data has been protected. Well-known techniques may exist to break the algorithm.

Remediation
Avoid using MD5 or SHA1 hashes as input to cryptographic functions or to store passwords. Node.js offers the following hashing algorithms: SHA224, SHA256, SHA384, and SHA512. Make sure you choose the most appropriate one, depending on your use case, security requirements and runtime constraints.

Violation Code Sample

const filename = process.argv[2]; 
import * as crypto from 'crypto'; 
import * as fs from 'fs'; 

const hash = crypto.createHash('md5'); 

const input = fs.createReadStream(filename); 
input.on('readable', () => { 
  const data = input.read(); 
  if (data) 
    hash.update(data); 
  else { 
    console.log(`${hash.digest('hex')} ${filename}`); 
  } 
});

Fixed Code Sample

const filename = process.argv[2]; 
import * as crypto from 'crypto'; 
import * as fs from 'fs'; 

const hash = crypto.createHash('sha256'); 

const input = fs.createReadStream(filename); 
input.on('readable', () => { 
  const data = input.read(); 
  if (data) 
    hash.update(data); 
  else { 
    console.log(`${hash.digest('hex')} ${filename}`); 
  }
 })

https://cwe.mitre.org/data/definitions/327.html https://www.owasp.org/index.php/Top_10_2013-A6-Sensitive_Data_Exposure https://www.owasp.org/index.php/Top_10-2017_A3-Sensitive_Data_Exposure