CVE-2015-5673 in Qualifier Portal
Summary
by MITRE
eventapp/lib/gcloud.rb in the ISUCON5 qualifier portal (aka eventapp) web application before 2015-10-30 makes improper popen calls, which allows remote attackers to execute arbitrary commands via an HTTP request that includes shell metacharacters in an argument to a "gcloud compute" command.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 06/26/2022
The vulnerability identified as CVE-2015-5673 resides within the ISUCON5 qualifier portal web application, specifically in the eventapp/lib/gcloud.rb component. This represents a critical command injection flaw that stems from improper use of system command execution functions. The vulnerability affects versions of the application released prior to October 30, 2015, making it a significant security weakness that could have been exploited for extended periods. The issue manifests when the application processes HTTP requests containing shell metacharacters that are subsequently passed as arguments to gcloud compute commands, creating an avenue for remote code execution.
The technical flaw constitutes a classic command injection vulnerability where user-supplied input is directly incorporated into system command execution without proper sanitization or validation. The application's use of improper popen calls demonstrates a failure in input handling and command construction practices that aligns with CWE-78, which specifically addresses improper neutralization of special elements used in OS commands. When an attacker crafts HTTP requests containing shell metacharacters such as semicolons, ampersands, or backticks, these characters are interpreted by the shell and can trigger unintended command execution. This vulnerability operates at the operating system level, bypassing application-level security controls and directly leveraging the underlying system's command processing capabilities.
The operational impact of this vulnerability extends far beyond simple data theft or service disruption. Remote attackers can execute arbitrary commands on the system hosting the vulnerable web application, potentially gaining full control over the server environment. This includes the ability to install malware, exfiltrate sensitive data, modify system configurations, or establish persistent backdoors. The attack surface is particularly concerning because the vulnerability is exploitable through standard HTTP requests, making it accessible to attackers without requiring specialized tools or privileged access. The gcloud compute commands typically involve cloud infrastructure management operations, which means successful exploitation could compromise cloud resources, potentially affecting multiple systems or services within the cloud environment. This vulnerability directly maps to attack techniques described in the MITRE ATT&CK framework under T1059.001 for command and script injection, and T1021.004 for remote services.
Mitigation strategies for CVE-2015-5673 must address both immediate remediation and long-term architectural improvements. The primary fix involves implementing proper input validation and sanitization of all user-supplied data before it is incorporated into system commands. This includes using parameterized command execution methods instead of direct string concatenation, employing proper escaping mechanisms, and implementing strict input filtering. Organizations should also consider adopting secure coding practices that align with OWASP Top Ten recommendations for preventing command injection vulnerabilities. Additionally, implementing proper access controls, network segmentation, and monitoring mechanisms can help detect and prevent exploitation attempts. The vulnerability underscores the importance of regular security updates and patch management, as the issue was resolved in the October 30, 2015 release, demonstrating that timely remediation is crucial for maintaining system security. Organizations should also implement automated vulnerability scanning and continuous monitoring to identify similar insecure coding practices across their application portfolios.