CVE-2024-24576
CVE-2024-24576
Weakness (CWE)
CVSS Vector
v3.1- Attack Vector
- Network
- Attack Complexity
- Low
- Privileges Required
- None
- User Interaction
- None
- Scope
- Changed
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Description
Rust is a programming language. The Rust Security Response WG was notified that the Rust standard library prior to version 1.77.2 did not properly escape arguments when invoking batch files (with the `bat` and `cmd` extensions) on Windows using the `Command`. An attacker able to control the arguments passed to the spawned process could execute arbitrary shell commands by bypassing the escaping. The severity of this vulnerability is critical for those who invoke batch files on Windows with untrusted arguments. No other platform or use is affected. The `Command::arg` and `Command::args` APIs state in their documentation that the arguments will be passed to the spawned process as-is, regardless of the content of the arguments, and will not be evaluated by a shell. This means it should be safe to pass untrusted input as an argument. On Windows, the implementation of this is more complex than other platforms, because the Windows API only provides a single string containing all the arguments to the spawned process, and it's up to the spawned process to split them. Most programs use the standard C run-time argv, which in practice results in a mostly consistent way arguments are splitted. One exception though is `cmd.exe` (used among other things to execute batch files), which has its own argument splitting logic. That forces the standard library to implement custom escaping for arguments passed to batch files. Unfortunately it was reported that our escaping logic was not thorough enough, and it was possible to pass malicious arguments that would result in arbitrary shell execution. Due to the complexity of `cmd.exe`, we didn't identify a solution that would correctly escape arguments in all cases. To maintain our API guarantees, we improved the robustness of the escaping code, and changed the `Command` API to return an `InvalidInput` error when it cannot safely escape an argument. This error will be emitted when spawning the process. The fix is included in Rust 1.77.2. Note that the new escaping logic for batch files errs on the conservative side, and could reject valid arguments. Those who implement the escaping themselves or only handle trusted inputs on Windows can also use the `CommandExt::raw_arg` method to bypass the standard library's escaping logic.
Comprehensive Technical Analysis of CVE-2024-24576
1. Vulnerability Assessment and Severity Evaluation
Vulnerability Description:
CVE-2024-24576 affects the Rust programming language's standard library prior to version 1.77.2. The vulnerability arises from improper escaping of arguments when invoking batch files (with .bat and .cmd extensions) on Windows using the Command API. This flaw allows an attacker to execute arbitrary shell commands by bypassing the escaping mechanism.
Severity Evaluation: The CVSS score of 10 indicates a critical vulnerability. This high score is justified by the potential for arbitrary command execution, which can lead to complete system compromise. The vulnerability is particularly severe for applications that invoke batch files on Windows with untrusted arguments.
2. Potential Attack Vectors and Exploitation Methods
Attack Vectors:
- Untrusted Input Handling: An attacker can exploit this vulnerability by injecting malicious arguments into a process that invokes batch files. This can be done through various input vectors such as user input fields, configuration files, or network data.
- Command Injection: The primary exploitation method involves command injection, where an attacker crafts input to execute arbitrary commands on the system.
Exploitation Methods:
- Crafting Malicious Arguments: An attacker can craft arguments that bypass the existing escaping logic, allowing them to inject and execute shell commands.
- Batch File Manipulation: By manipulating the arguments passed to batch files, an attacker can execute commands that compromise the system, such as downloading and executing malware, modifying system files, or exfiltrating data.
3. Affected Systems and Software Versions
Affected Systems:
- Windows Operating Systems: The vulnerability specifically affects Windows systems where batch files are invoked using the Rust standard library.
Affected Software Versions:
- Rust Standard Library: Versions prior to 1.77.2 are affected. The vulnerability is fixed in Rust 1.77.2.
4. Recommended Mitigation Strategies
Immediate Mitigation:
- Update Rust: Upgrade to Rust version 1.77.2 or later, which includes the fix for this vulnerability.
- Input Validation: Ensure that all inputs passed to the
CommandAPI are thoroughly validated and sanitized. - Use
CommandExt::raw_arg: For trusted inputs, use theCommandExt::raw_argmethod to bypass the standard library's escaping logic, but ensure that this is done with caution and only for trusted inputs.
Long-Term Mitigation:
- Code Review: Conduct a thorough code review to identify and mitigate similar vulnerabilities in other parts of the codebase.
- Security Training: Provide training for developers on secure coding practices, especially regarding input handling and command execution.
- Regular Updates: Implement a regular update and patch management process to ensure that all software dependencies are up-to-date.
5. Impact on Cybersecurity Landscape
Immediate Impact:
- System Compromise: The vulnerability can lead to complete system compromise, including data theft, unauthorized access, and system corruption.
- Supply Chain Attacks: Applications that rely on Rust and invoke batch files on Windows are at risk, potentially affecting a wide range of software and services.
Long-Term Impact:
- Increased Awareness: This vulnerability highlights the importance of secure input handling and the need for robust escaping mechanisms in programming languages.
- Enhanced Security Practices: The incident may prompt developers and organizations to adopt more stringent security practices and conduct regular security audits.
6. Technical Details for Security Professionals
Technical Overview:
- Escaping Logic: The Rust standard library's escaping logic for arguments passed to batch files was found to be insufficient. The complexity of
cmd.exe's argument splitting logic contributed to this vulnerability. - API Changes: The fix includes improved escaping logic and the introduction of an
InvalidInputerror when the library cannot safely escape an argument. This error is emitted when spawning the process. - Bypass Mechanism: The
CommandExt::raw_argmethod allows developers to bypass the standard library's escaping logic for trusted inputs.
Detection and Monitoring:
- Log Analysis: Monitor system logs for unusual command executions or errors related to the
CommandAPI. - Intrusion Detection: Implement intrusion detection systems (IDS) to detect and alert on suspicious command executions.
- Code Analysis: Use static and dynamic code analysis tools to identify potential command injection vulnerabilities in the codebase.
Conclusion: CVE-2024-24576 is a critical vulnerability that underscores the importance of secure input handling and robust escaping mechanisms. Organizations should prioritize updating to Rust 1.77.2 and implementing comprehensive input validation and sanitization practices to mitigate the risk. The incident serves as a reminder of the potential consequences of command injection vulnerabilities and the need for vigilant security practices.