CWE-77

What is CWE-77 (Improper Neutralization of Special Elements used in a Command (Command Injection))?

The product constructs all or part of a command using externally-influenced input but does not neutralize special elements that could modify the intended command.

Vulnerability Insights

Improper Neutralization of Special Elements used in a Command (Command Injection) (CWE-77) represents a significant security risk across modern software systems. This weakness enables attackers to exploit injection flaws in applications, potentially leading to unauthorized access, data exfiltration, or remote code execution. Organizations must implement defense-in-depth strategies combining static analysis, runtime monitoring, and binary analysis to detect and mitigate these vulnerabilities.

Impact on Systems

• Remote Code Execution (RCE): Full control over the server running the application
• Lateral Movement: Using the compromised server to attack internal network
• Data Exfiltration: Dumping credentials or sensitive intellectual property

Real-World Attack Scenario

An attacker targets a 'network diagnostic' tool that accepts a hostname to resolve. They supply google.com; cat /etc/shadow as the input. Because the parameter is concatenated directly into the shell string without sanitization, the server resolves the hostname and then outputs the highly sensitive password hash file in the response.

Code Examples

Vulnerable Implementation

import subprocess
# VULNERABLE: Untrusted input concatenated directly
output = subprocess.getoutput("nslookup " + user_input)

Secure Alternative

import subprocess
# SECURE: Pass arguments as a list, avoiding shell interpretation
output = subprocess.check_output(["nslookup", user_input])

Detection with Precogs AI

Precogs AI detects command injection by analyzing how user-controlled data reaches command execution functions like system(), exec(), and popen(). Our binary analysis engine examines compiled artifacts without requiring source code access, identifying CWE-77 patterns in vendor software, containers, firmware, and third-party libraries.

Remediation

Implement proper injection controls following secure coding guidelines. Use automated scanning tools like Precogs AI to continuously monitor for CWE-77 vulnerabilities across your software supply chain. Apply the principle of least privilege and validate all inputs from untrusted sources.