BYOVD Scanner: Driver
Vulnerability Detection

The BYOVD Problem

"Bring Your Own Vulnerable Driver" attacks exploit signed drivers with security flaws to gain kernel execution. Identifying these drivers proactively is essential for security teams.

Scanner Architecture

Detection Methods

• Signature Analysis — Known vulnerable driver signatures
• Function Analysis — Dangerous IOCTL handlers
• Import Analysis — Suspicious API usage patterns
• String Analysis — Known debug strings and paths
• Behavioral Patterns — Memory access without validation

IOC Database

The scanner maintains an IOC (Indicator of Compromise) cache containing:

IOC Types:
  - Driver file hashes (MD5, SHA1, SHA256)
  - Signer information (thumbprint, name)
  - Export function names
  - IOCTL code patterns
  - Known vulnerable version ranges
  - Vendor blocklist status

Static Analysis Pipeline

1. PE Header Analysis

• Digital certificate information
• Section characteristics (executable + writable)
• Import table contents
• Export table analysis

2. Code Pattern Matching

Vulnerable drivers often share code patterns:

• IOCTL handlers without parameter validation
• Direct memory access from user-controlled input
• Pointer dereferencing without null checks
• Buffer operations with unchecked sizes

3. Heuristic Scoring

Each driver receives a risk score based on:

Scoring factors:
  - Known vulnerable signature match: +50
  - Suspicious IOCTL patterns: +20
  - Dangerous imports (MmMapIoSpace, etc.): +15
  - Writable + Executable sections: +10
  - Debug strings present: +5
  - Valid Microsoft signature: -20

Output Formats

Technical Report (output_tech.txt)

Detailed analysis for security researchers:

• Per-driver vulnerability analysis
• Specific indicators detected
• Confidence scores with reasoning
• Remediations or mitigations

JSON Output (output.json)

Machine-readable format for automation:

• Structured driver metadata
• Normalized IOC data
• Risk scores and classifications
• SIEM integration ready

Scanner Operation

Collection Phase

1. Enumerate driver store paths
2. Collect .sys files from various sources:
   - C:\Windows\System32\drivers
   - Driver Store
   - Third-party driver directories

Analysis Phase

3. For each driver:
   - Calculate file hashes
   - Parse PE headers
   - Check IOC cache
   - Perform heuristic analysis
   - Generate risk score

Reporting Phase

4. Aggregate results
5. Generate reports in all formats
6. Update IOC cache with new findings

Integration with kdmapper

The scanner helps identify drivers suitable for kdmapper:

1. Scan potential target drivers
2. Review output for exploitable vulnerabilities
3. Verify driver is signed and likely whitelisted
4. Use with kdmapper for driver loading

What I Learned

Building this scanner taught me about driver vulnerabilities at scale. The most interesting insight is how similar vulnerable drivers are: missing parameter validation, unchecked pointers, and dangerous IOCTL designs that trust user input too much.

Applications

• Blue Team — Identify vulnerable drivers in environment
• Red Team — Find exploitable drivers for testing
• Driver Developers — Understand common vulnerabilities
• Security Analysts — Track BYOVD trends