Performing Cryptographic Audit of Application
Overview
A cryptographic audit systematically reviews an application's use of cryptographic primitives, protocols, and key management to identify vulnerabilities such as weak algorithms, insecure modes, hardcoded keys, insufficient entropy, and protocol misconfigurations. This guide covers building an automated crypto audit tool that scans Python and configuration files for common cryptographic weaknesses.
Objectives
- Detect usage of deprecated algorithms (MD5, SHA-1, DES, RC4)
- Identify insecure cipher modes (ECB) and padding schemes
- Find hardcoded keys, passwords, and secrets in source code
- Verify TLS/SSL configuration strength
- Check key derivation function parameters
- Validate random number generator usage
- Produce a structured audit report with findings and remediation
Key Concepts
Cryptographic Weakness Categories
| Category | Examples | Risk Level |
|---|---|---|
| Weak Hashing | MD5, SHA-1 for integrity/signatures | High |
| Insecure Encryption | DES, 3DES, RC4, Blowfish | High |
| Bad Cipher Mode | ECB mode for any block cipher | High |
| Insufficient Key Size | RSA < 2048, AES-128 for long-term | Medium |
| Hardcoded Secrets | Keys/passwords in source code | Critical |
| Weak KDF | Low iteration PBKDF2, plain MD5 | High |
| Poor Entropy | time-based seeds, predictable IVs | High |
| Deprecated Protocols | SSLv3, TLS 1.0, TLS 1.1 | High |
Security Considerations
- Review both application code and configuration files
- Check third-party dependencies for known crypto vulnerabilities
- Verify certificates and TLS configurations on deployed servers
- Ensure secrets are loaded from environment variables or vaults
- Review key storage and rotation practices
Validation Criteria
- [ ] Scanner detects all injected test weaknesses
- [ ] MD5/SHA-1 usage for security purposes is flagged
- [ ] ECB mode usage is flagged
- [ ] Hardcoded keys/passwords are detected
- [ ] Weak KDF parameters are identified
- [ ] Report includes severity, location, and remediation
- [ ] False positive rate is below 10%
Compliance Framework Mapping
This skill supports compliance evidence collection across multiple frameworks:
- SOC 2: CC6.7 (Restriction on Transmission), CC6.1 (Logical Access)
- ISO 27001: A.10.1 (Cryptographic Controls)
- NIST 800-53: SC-12 (Cryptographic Key Management), SC-13 (Cryptographic Protection), SC-8 (Transmission Confidentiality)
- NIST CSF: PR.DS (Data Security)
Claw GRC Tip: When this skill is executed by a registered agent, compliance evidence is automatically captured and mapped to the relevant controls in your active frameworks.
Deploying This Skill with Claw GRC
Agent Execution
Register this skill with your Claw GRC agent for automated execution:
# Install via CLI
npx claw-grc skills add performing-cryptographic-audit-of-application
# Or load dynamically via MCP
grc.load_skill("performing-cryptographic-audit-of-application")Audit Trail Integration
When executed through Claw GRC, every step of this skill generates tamper-evident audit records:
- SHA-256 chain hashing ensures no step can be modified after execution
- Evidence artifacts (configs, scan results, logs) are automatically attached to relevant controls
- Trust score impact — successful execution increases your agent's trust score
Continuous Compliance
Schedule this skill for recurring execution to maintain continuous compliance posture. Claw GRC monitors for drift and alerts when re-execution is needed.