CVE-2015-7541 in Colorscore Gem
Summary
by MITRE
The initialize method in the Histogram class in lib/colorscore/histogram.rb in the colorscore gem before 0.0.5 for Ruby allows context-dependent attackers to execute arbitrary code via shell metacharacters in the (1) image_path, (2) colors, or (3) depth variable.
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Analysis
by VulDB Data Team • 11/18/2024
The CVE-2015-7541 vulnerability represents a critical command injection flaw within the colorscore ruby gem, specifically affecting versions prior to 005. This vulnerability exists in the Histogram class's initialize method within the lib/colorscore/histogram.rb file, where the gem fails to properly sanitize user-supplied input before incorporating it into system commands. The flaw affects three distinct input parameters including image_path, colors, and depth variables, creating multiple attack vectors for malicious actors to exploit. The vulnerability's context-dependent nature means that successful exploitation requires specific conditions related to how the gem is used within applications, making it particularly dangerous in environments where user input is processed without proper validation. This type of vulnerability falls under the CWE-78 category of improper neutralization of special elements used in OS commands, which is a well-documented weakness in software security practices. The ATT&CK framework categorizes this as a command injection technique, where adversaries leverage application vulnerabilities to execute arbitrary commands on the underlying operating system.
The technical implementation of this vulnerability stems from the gem's failure to properly escape or filter shell metacharacters in user-provided input parameters. When the initialize method processes the image_path, colors, or depth variables, it directly incorporates these values into shell commands without adequate sanitization or validation. Attackers can craft malicious input containing special shell characters such as semicolons, ampersands, or backticks that get interpreted by the operating system as command delimiters or operators. This allows an attacker to inject additional commands that execute with the privileges of the application process, potentially leading to complete system compromise. The vulnerability is particularly concerning because it affects multiple input points within the same method, increasing the attack surface and providing multiple pathways for exploitation. The flaw essentially creates a situation where user-controllable data becomes part of an operating system command execution pipeline, bypassing normal application security controls.
The operational impact of this vulnerability extends beyond simple code execution, potentially allowing attackers to gain full control over systems running vulnerable applications. An attacker who successfully exploits this vulnerability could execute arbitrary commands including but not limited to file manipulation, network reconnaissance, privilege escalation, or data exfiltration. The vulnerability affects ruby applications that utilize the colorscore gem for image color analysis or processing, making it particularly dangerous in web applications where user input is commonly accepted. The severity is amplified by the fact that the vulnerability can be exploited without requiring special privileges or access to the system, as long as the vulnerable gem is installed and used within an application. Organizations using this gem in production environments face significant risk, as the vulnerability could be exploited by external attackers to compromise entire systems, particularly in cloud or shared hosting environments where multiple applications may be running on the same infrastructure. The vulnerability's persistence in the codebase until version 005 indicates a prolonged exposure period, increasing the likelihood of successful exploitation by threat actors who may have already developed specific attack methods.
Mitigation strategies for CVE-2015-7541 should focus on immediate remediation through version upgrading to colorscore 005 or later, which contains the necessary input validation and sanitization patches. Organizations should also implement comprehensive input validation at multiple layers, including application-level filtering of shell metacharacters and proper escaping of user-supplied data before any system command execution. The implementation of principle of least privilege should be enforced, ensuring that applications run with minimal required permissions to limit potential damage from successful exploits. Additionally, organizations should conduct thorough code reviews and security testing to identify similar vulnerabilities in other components of their software stack, particularly in gems that handle file operations or system command execution. Network monitoring and intrusion detection systems should be configured to detect suspicious command execution patterns that may indicate exploitation attempts. The vulnerability serves as a reminder of the importance of proper input validation and the principle of never trusting user input, which aligns with security best practices outlined in various industry standards including the OWASP Top Ten and NIST cybersecurity guidelines. Regular security assessments and dependency updates should be implemented as part of standard security operations to prevent similar vulnerabilities from remaining undetected for extended periods.