CVE-2005-3750 in Web Browser
Summary
by MITRE
Opera before 8.51 on Linux and Unix systems allows remote attackers to execute arbitrary code via shell metacharacters (backticks) in a URL that another product provides in a command line argument when launching Opera.
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Analysis
by VulDB Data Team • 06/11/2019
This vulnerability exists in Opera web browsers version 8.50 and earlier on Linux and Unix operating systems, representing a critical command injection flaw that enables remote attackers to execute arbitrary code on affected systems. The vulnerability stems from improper input validation when Opera processes URLs that contain shell metacharacters, specifically backticks, which are commonly used in Unix-like systems for command substitution. When Opera launches and processes a URL containing these metacharacters through command line arguments, the browser fails to properly sanitize the input before passing it to the underlying shell environment, creating a direct path for malicious command execution.
The technical implementation of this vulnerability involves the browser's handling of external URL references that are passed as command line arguments during the Opera launch process. When a user visits a malicious website containing a URL with backtick characters, these metacharacters are interpreted by the Unix shell as command substitution operators, allowing an attacker to inject and execute arbitrary shell commands with the privileges of the user running Opera. This represents a classic command injection vulnerability that falls under the CWE-77 category, specifically CWE-77: Improper Neutralization of Special Elements used in a Command. The flaw demonstrates poor input validation and sanitization practices where the application does not properly escape or filter special shell characters before using them in system calls.
The operational impact of this vulnerability is severe and far-reaching, as it allows remote attackers to execute arbitrary code on target systems without requiring any local privileges or user interaction beyond visiting a malicious webpage. Attackers can leverage this vulnerability to gain complete control over the affected system, potentially leading to data theft, system compromise, or further network infiltration. The attack vector is particularly dangerous because it requires no user interaction beyond visiting a malicious site, making it a significant threat in phishing campaigns or when users browse untrusted websites. This vulnerability aligns with ATT&CK technique T1059.001 for Command and Scripting Interpreter, specifically focusing on the use of Unix shell commands for execution. The risk is amplified in environments where Opera is used with elevated privileges or in corporate settings where users may have access to sensitive data or network resources.
Mitigation strategies for this vulnerability involve immediate patching of Opera installations to version 8.51 or later, which contains proper input sanitization for shell metacharacters. Organizations should also implement network-level protections such as web application firewalls that can detect and block URLs containing suspicious shell metacharacters, though this approach is less reliable than proper input validation. System administrators should consider running Opera with reduced privileges and implementing additional security measures such as sandboxing or containerization to limit the potential impact of successful exploitation. The vulnerability highlights the importance of proper input validation and output encoding in preventing command injection attacks, and organizations should review their applications for similar flaws in command execution paths. Regular security audits and vulnerability assessments should include testing for command injection vulnerabilities, particularly in applications that process external input through shell commands, as this represents a fundamental security weakness that can lead to complete system compromise.