Resolve vulnerability: Use of a broken or risky cryptographic algorithm

MR created from vulnerability: Use of a broken or risky cryptographic algorithm

AI GENERATED FIX

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Description:

The SHA-1 message-digest algorithm has been cryptographically broken and is unsuitable for further use. It is recommended that the SHA-3, or BLAKE2 family of algorithms be used for non-password based cryptographic hashes instead. For password based cryptographic hashes, consider using the bcrypt or Argon2id family of cryptographic hashes.

Hashing values using BLAKE2:

fileContents := []byte("some file contents to create hash for")
blake2bHasher, err := blake2b.New512(nil)
if err != nil {
  log.Fatal(err)
}
hashedValue := blake2bHasher.Sum(fileContents)
fmt.Printf("%s\n", hex.EncodeToString(hashedValue))

Hashing and securely comparing passwords using Argon2id:

type argonParameters struct {
  variant     string
  version     int
  memory      uint32
  iterations  uint32
  parallelism uint8
  saltLength  uint32
  keyLength   uint32
}

func (a argonParameters) StringFormat(salt, derivedKey []byte) string {
  encodedSalt := base64.RawStdEncoding.EncodeToString(salt)
  encodedKey := base64.RawStdEncoding.EncodeToString(derivedKey)

  return fmt.Sprintf("$argon2id$v=%d$m=%d,t=%d,p=%d$%s$%s",
    argon2.Version,
    a.memory,
    a.iterations,
    a.parallelism,
    encodedSalt,
    encodedKey,
  )
}

func main() {
  // Initialize Argon2id parameters
  p := argonParameters{
    memory:      64 * 1024,
    iterations:  3,
    parallelism: 2,
    saltLength:  16,
    keyLength:   32,
  }

  // Generate random salt (to be stored alongside derived hash key)
  salt := make([]byte, p.saltLength)
  if _, err := io.ReadFull(rand.Reader, salt); err != nil {
    log.Fatal(err)
  }

  usersPassword := []byte("User's Very S3cur3P4ss@rd@#$%")

  var derivedKey []byte
  // Create key hash derived from user's password
  {
    derivedKey = argon2.IDKey(usersPassword, salt, p.iterations, p.memory, p.parallelism,
p.keyLength)
    // store p.StringFormat(...) result in a data store...
    fmt.Printf("%s\n", p.StringFormat(salt, derivedKey))
  }

  // Verify a user's password against key
  {
    keyToCompare := argon2.IDKey(usersPassword, salt, p.iterations, p.memory, p.parallelism,
p.keyLength)

    // Use subtle.ConstantTimeCompare(..., ...) to ensure no side channel leaks used in timing
attacks
    if subtle.ConstantTimeCompare(derivedKey, keyToCompare) == 1 {
      fmt.Printf("Passwords match\n")
    } else {
      fmt.Printf("Passwords do not match\n")
    }
  }
}

For more information on password storage see OWASP's guide: https://cheatsheetseries.owasp.org/cheatsheets/Password_Storage_Cheat_Sheet.html

• Severity: low
• Confidence: unknown
• Location: internal/git/conflict/resolve.go:3

Analysis:

The vulnerability report indicates the use of a broken or risky cryptographic algorithm, specifically pointing to the use of SHA-1 (CWE-327). The vulnerable code section highlights the import of the crypto/sha1 package.

SHA-1 is considered cryptographically weak and has been practically broken. It's vulnerable to collision attacks, which means it's possible to find two different inputs that produce the same hash output. This can lead to security issues in certain contexts, particularly when SHA-1 is used for digital signatures or integrity checks.

However, in this specific code context, SHA-1 is not being used for cryptographic security purposes. It's being used to generate a unique identifier for a section in a conflict resolution process:

sectionID = fmt.Sprintf("%x_%d_%d", sha1.Sum([]byte(path)), l.oldIndex, l.newIndex)

This usage doesn't rely on the cryptographic security properties of SHA-1. It's simply using SHA-1 as a quick way to generate a unique identifier based on the path and some indices. The collision resistance of SHA-1 is not critical for this particular use case.

While it's generally good practice to avoid deprecated algorithms like SHA-1, in this specific context, the use of SHA-1 does not introduce a significant security vulnerability. The generated sectionID is used internally for conflict resolution and is not used for any security-critical operations.

Summary:

1. The reported vulnerability is the use of a broken or risky cryptographic algorithm, specifically the use of SHA-1 (CWE-327).

2. While the use of SHA-1 in this context doesn't pose a significant security risk as it's not used for cryptographic purposes, it's still good practice to use a more secure hash function. The fix provided replaces crypto/sha1 with crypto/sha256.

3. To implement this change fully, you would also need to update the line where sha1.Sum is used:

// Old code
sectionID = fmt.Sprintf("%x_%d_%d", sha1.Sum([]byte(path)), l.oldIndex, l.newIndex)

// New code
sectionID = fmt.Sprintf("%x_%d_%d", sha256.Sum256([]byte(path)), l.oldIndex, l.newIndex)

This change maintains the functionality of generating a unique identifier while using a more secure hash function. It's worth noting that this change might slightly increase the length of the sectionID string, as SHA-256 produces a longer hash than SHA-1. However, this shouldn't affect the overall functionality of the code.

While this isn't a critical security fix in this context, it aligns with best practices and removes the use of a deprecated cryptographic function.

Identifiers:

• Gosec Rule ID gosec.G505-1
• CWE-327
• A3:2017 - Sensitive Data Exposure
• A02:2021 - Cryptographic Failures
• go-lang-crypto-blocklist-sha1-atomic
• SAST Rules ID - go_blocklist_rule-blocklist-sha1