solana-vulnerability-scanner

SKILL.md

Solana Vulnerability Scanner

1. Purpose

Systematically scan Solana programs (native and Anchor framework) for platform-specific security vulnerabilities related to cross-program invocations, account validation, and program-derived addresses. This skill encodes 6 critical vulnerability patterns unique to Solana's account model.

2. When to Use This Skill

Auditing Solana programs (native Rust or Anchor)

Reviewing cross-program invocation (CPI) logic

Validating program-derived address (PDA) implementations

Pre-launch security assessment of Solana protocols

Reviewing account validation patterns

Assessing instruction introspection logic

3. Platform Detection

File Extensions & Indicators

Rust files: .rs

Language/Framework Markers

// Native Solana program indicators
use solana_program::{
    account_info::AccountInfo,
    entrypoint,
    entrypoint::ProgramResult,
    pubkey::Pubkey,
    program::invoke,
    program::invoke_signed,
};

entrypoint!(process_instruction);

// Anchor framework indicators
use anchor_lang::prelude::*;

#[program]
pub mod my_program {
    pub fn initialize(ctx: Context<Initialize>) -> Result<()> {
        // Program logic
    }
}

#[derive(Accounts)]
pub struct Initialize<'info> {
    #[account(mut)]
    pub authority: Signer<'info>,
}

// Common patterns
AccountInfo, Pubkey
invoke(), invoke_signed()
Signer<'info>, Account<'info>
#[account(...)] with constraints
seeds, bump

Project Structure

programs/*/src/lib.rs - Program implementation

Anchor.toml - Anchor configuration

Cargo.toml with solana-program or anchor-lang

tests/ - Program tests

Tool Support

Trail of Bits Solana Lints: Rust linters for Solana

Installation: Add to Cargo.toml

anchor test: Built-in testing framework

Solana Test Validator: Local testing environment

4. How This Skill Works

When invoked, I will:

Search your codebase for Solana/Anchor programs

Analyze each program for the 6 vulnerability patterns

Report findings with file references and severity

Provide fixes for each identified issue

Check account validation and CPI security

5. Example Output

6. Vulnerability Patterns (6 Patterns)

I check for 6 critical vulnerability patterns unique to Solana. For detailed detection patterns, code examples, mitigations, and testing strategies, see VULNERABILITY_PATTERNS.md.

Pattern Summary:

Arbitrary CPI ⚠️ CRITICAL - User-controlled program IDs in CPI calls

Improper PDA Validation ⚠️ CRITICAL - Using create_program_address without canonical bump

Missing Ownership Check ⚠️ HIGH - Deserializing accounts without owner validation

Missing Signer Check ⚠️ CRITICAL - Authority operations without is_signer check

Sysvar Account Check ⚠️ HIGH - Spoofed sysvar accounts (pre-Solana 1.8.1)

Improper Instruction Introspection ⚠️ MEDIUM - Absolute indexes allowing reuse

For complete vulnerability patterns with code examples, see VULNERABILITY_PATTERNS.md.

7. Scanning Workflow

Step 1: Platform Identification

Verify Solana program (native or Anchor)

Check Solana version (1.8.1+ for sysvar security)

Locate program source (programs/*/src/lib.rs)

Identify framework (native vs Anchor)

Step 2: CPI Security Review

# Find all CPI calls
rg "invoke\(|invoke_signed\(" programs/

# Check for program ID validation before each
# Should see program ID checks immediately before invoke

For each CPI:

 Program ID validated before invocation

 Cannot pass user-controlled program accounts

 Anchor: Uses Program<'info, T> type

Step 3: PDA Validation Check

# Find PDA usage
rg "find_program_address|create_program_address" programs/
rg "seeds.*bump" programs/

# Anchor: Check for seeds constraints
rg "#\[account.*seeds" programs/

For each PDA:

 Uses find_program_address() or Anchor seeds constraint

 Bump seed stored and reused

 Not using user-provided bump

Step 4: Account Validation Sweep

# Find account deserialization
rg "try_from_slice|try_deserialize" programs/

# Should see owner checks before deserialization
rg "\.owner\s*==|\.owner\s*!=" programs/

For each account used:

 Owner validated before deserialization

 Signer check for authority accounts

 Anchor: Uses Account<'info, T> and Signer<'info>

Step 5: Instruction Introspection Review

# Find instruction introspection usage
rg "load_instruction_at|load_current_index|get_instruction_relative" programs/

# Check for checked versions
rg "load_instruction_at_checked|load_current_index_checked" programs/

 Using checked functions (Solana 1.8.1+)

 Using relative indexing

 Proper correlation validation

Step 6: Trail of Bits Solana Lints

# Add to Cargo.toml
[dependencies]
solana-program = "1.17"  # Use latest version

[lints.clippy]
# Enable Solana-specific lints
# (Trail of Bits solana-lints if available)

8. Reporting Format

Finding Template

## [CRITICAL] Arbitrary CPI - Unchecked Program ID

**Location**: `programs/vault/src/lib.rs:145-160` (withdraw function)

**Description**:
The `withdraw` function performs a CPI to transfer SPL tokens without validating that the provided `token_program` account is actually the SPL Token program. An attacker can provide a malicious program that appears to perform a transfer but actually steals tokens or performs unauthorized actions.

**Vulnerable Code**:
```rust
// lib.rs, line 145
pub fn withdraw(ctx: Context<Withdraw>, amount: u64) -> Result<()> {
    let token_program = &ctx.accounts.token_program;

    // WRONG: No validation of token_program.key()!
    invoke(
        &spl_token::instruction::transfer(...),
        &[
            ctx.accounts.vault.to_account_info(),
            ctx.accounts.destination.to_account_info(),
            ctx.accounts.authority.to_account_info(),
            token_program.to_account_info(),  // UNVALIDATED
        ],
    )?;
    Ok(())
}

Attack Scenario:

Attacker deploys malicious "token program" that logs transfer instruction but doesn't execute it

Attacker calls withdraw() providing malicious program as token_program

Vault's authority signs the transaction

Malicious program receives CPI with vault's signature

Malicious program can now impersonate vault and drain real tokens

Recommendation:
Use Anchor's Program<'info, Token> type:

use anchor_spl::token::{Token, Transfer};

#[derive(Accounts)]
pub struct Withdraw<'info> {
    #[account(mut)]
    pub vault: Account<'info, TokenAccount>,
    #[account(mut)]
    pub destination: Account<'info, TokenAccount>,
    pub authority: Signer<'info>,
    pub token_program: Program<'info, Token>,  // Validates program ID automatically
}

pub fn withdraw(ctx: Context<Withdraw>, amount: u64) -> Result<()> {
    let cpi_accounts = Transfer {
        from: ctx.accounts.vault.to_account_info(),
        to: ctx.accounts.destination.to_account_info(),
        authority: ctx.accounts.authority.to_account_info(),
    };

    let cpi_ctx = CpiContext::new(
        ctx.accounts.token_program.to_account_info(),
        cpi_accounts,
    );

    anchor_spl::token::transfer(cpi_ctx, amount)?;
    Ok(())
}

References:

building-secure-contracts/not-so-smart-contracts/solana/arbitrary_cpi

Trail of Bits lint: unchecked-cpi-program-id

---

## 9. Priority Guidelines

### Critical (Immediate Fix Required)
- Arbitrary CPI (attacker-controlled program execution)
- Improper PDA validation (account spoofing)
- Missing signer check (unauthorized access)

### High (Fix Before Launch)
- Missing ownership check (fake account data)
- Sysvar account check (authentication bypass, pre-1.8.1)

### Medium (Address in Audit)
- Improper instruction introspection (logic bypass)

---

## 10. Testing Recommendations

### Unit Tests
```rust
#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    #[should_panic]
    fn test_rejects_wrong_program_id() {
        // Provide wrong program ID, should fail
    }

    #[test]
    #[should_panic]
    fn test_rejects_non_canonical_pda() {
        // Provide non-canonical bump, should fail
    }

    #[test]
    #[should_panic]
    fn test_requires_signer() {
        // Call without signature, should fail
    }
}

Integration Tests (Anchor)

import * as anchor from "@coral-xyz/anchor";

describe("security tests", () => {
  it("rejects arbitrary CPI", async () => {
    const fakeTokenProgram = anchor.web3.Keypair.generate();

    try {
      await program.methods
        .withdraw(amount)
        .accounts({
          tokenProgram: fakeTokenProgram.publicKey, // Wrong program
        })
        .rpc();

      assert.fail("Should have rejected fake program");
    } catch (err) {
      // Expected to fail
    }
  });
});

Solana Test Validator

# Run local validator for testing
solana-test-validator

# Deploy and test program
anchor test

11. Additional Resources

Building Secure Contracts: building-secure-contracts/not-so-smart-contracts/solana/

Trail of Bits Solana Lints: https://github.com/trailofbits/solana-lints

Anchor Documentation: https://www.anchor-lang.com/

Solana Program Library: https://github.com/solana-labs/solana-program-library

Solana Cookbook: https://solanacookbook.com/

12. Quick Reference Checklist

Before completing Solana program audit:

CPI Security (CRITICAL):

 ALL CPI calls validate program ID before invoke()

 Cannot use user-provided program accounts

 Anchor: Uses Program<'info, T> type

PDA Security (CRITICAL):

 PDAs use find_program_address() or Anchor seeds constraint

 Bump seed stored and reused (not user-provided)

 PDA accounts validated against canonical address

Account Validation (HIGH):

 ALL accounts check owner before deserialization

 Native: Validates account.owner == expected_program_id

 Anchor: Uses Account<'info, T> type

Signer Validation (CRITICAL):

 ALL authority accounts check is_signer

 Native: Validates account.is_signer == true

 Anchor: Uses Signer<'info> type

Sysvar Security (HIGH):

 Using Solana 1.8.1+

 Using checked functions: load_instruction_at_checked()

 Sysvar addresses validated

Instruction Introspection (MEDIUM):

 Using relative indexes for correlation

 Proper validation between related instructions

 Cannot reuse same instruction across multiple calls

Testing:

 Unit tests cover all account validation

 Integration tests with malicious inputs

 Local validator testing completed

 Trail of Bits lints enabled and passing