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Submission Details
Impact: high
Likelihood: high
Invalid

foundry.toml Enables FFI Globally, Allowing All Tests to Execute System Commands

georgibuilds

Root + Impact

The Foundry configuration enables FFI (Foreign Function Interface) globally with ffi = true, removing the security safeguard that prevents tests from executing system commands. This enables Finding #5 and allows any test to compromise user systems.

Description

  • FFI is disabled by default as a security measure

Configuration explicitly enables FFI for all tests

  • Malicious tests can execute arbitrary commands without warnings

# foundry.toml
[profile.default]
src = "src"
out = "out"
libs = ["lib"]
ffi = true # ❌ Enables system command execution globally
evm_version = "paris"
​
function testPwned() public {
string[] memory cmds = new string[](2);
cmds[0] = "touch";
cmds[1] = string.concat("youve-been-pwned");
cheatCodes.ffi(cmds);
}

Risk

Likelihood:

  • Applied automatically when running any Foundry command

No user prompt or warning about FFI being active

  • Affects all test files in the project

  • Combined with Finding #5 for automatic exploitation

Impact:

  • Enables all FFI-based attacks (like Finding #5)

Removes default security protection

  • Silent enablement without user awareness

  • Supply chain attack vector for malicious developers

  • Persistent risk across all testing

Proof of Concept

This demonstrates that FFI is active by successfully executing a command that would normally be blocked.

function test_ffiIsEnabled() public {
string[] memory cmds = new string[](2);
cmds[0] = "echo";
cmds[1] = "FFI is enabled!";
// If ffi = false, this would error: "FFI is not enabled"
// Because ffi = true, it executes successfully
cheatCodes.ffi(cmds);
}

Recommended Mitigation

Disable FFI by default to restore the security safeguard, requiring explicit opt-in for legitimate use cases.

[profile.default]
src = "src"
out = "out"
libs = ["lib"]
- ffi = true
+ ffi = false
evm_version = "paris"
Updates

Lead Judging Commences

ai-first-flight-judge Lead Judge about 18 hours ago
Submission Judgement Published
Invalidated
Reason: Incorrect statement

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