Solana Vulnerability Scanner

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:

1. Search your codebase for Solana/Anchor programs
2. Analyze each program for the 6 vulnerability patterns
3. Report findings with file references and severity, above them a coverage table carrying a verdict for every pattern
4. Provide fixes for each identified issue
5. 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:

1. Arbitrary CPI ⚠️ CRITICAL - User-controlled program IDs in CPI calls
2. Improper PDA Validation ⚠️ CRITICAL - Using create_program_address without canonical bump
3. Missing Ownership Check ⚠️ HIGH - Deserializing accounts without owner validation
4. Missing Signer Check ⚠️ CRITICAL - Authority operations without is_signer check
5. Sysvar Account Check ⚠️ HIGH - Spoofed sysvar accounts (pre-Solana 1.8.1)
6. 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

1. Verify Solana program (native or Anchor)
2. Check Solana version (1.8.1+ for sysvar security)
3. Locate program source (programs/*/src/lib.rs)
4. 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

Coverage Table

Report on every pattern in §6, whether or not it turned anything up. Emit this table above the findings, with all 6 rows present:

Each verdict is one of:

• found — cite file:line and write the finding up in full below.
• clear — the pattern applies to this program and the program handles it. Name the constraint, account type, or check you searched for, so a reader can repeat the search.
• n/a — the pattern cannot apply here. Give the reason in one clause ("this program makes no CPI calls"). Not having looked is not n/a. Pattern 5 is version-scoped (pre-Solana 1.8.1): cite the solana-program version the program targets rather than dropping the row, since "targets 1.17, fixed upstream" and "did not look" are otherwise the same answer.

A table with fewer than 6 rows is an incomplete scan and must be reported as one. A row whose Verdict cell is empty is incomplete in the same way: row 1 above is filled in to show the shape, and every row is filled in the same way before the report is done. Six clear verdicts is a result a reader can act on. A report that covers two patterns and says nothing about the other four reads exactly like a clean program, and that is the failure this table exists to prevent.

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**:
1. Attacker deploys malicious "token program" that logs transfer instruction but doesn't execute it
2. Attacker calls withdraw() providing malicious program as token_program
3. Vault's authority signs the transaction
4. Malicious program receives CPI with vault's signature
5. Malicious program can now impersonate vault and drain real tokens

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