CVE-2017-17526 in Giac
Summary
by MITRE
Input.cc in Bernard Parisse Giac 1.2.3.57 does not validate strings before launching the program specified by the BROWSER environment variable, which might allow remote attackers to conduct argument-injection attacks via a crafted URL.
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Analysis
by VulDB Data Team • 01/27/2021
The vulnerability identified as CVE-2017-17526 resides within the Input.cc component of Giac 1.2.3.57, a computer algebra system developed by Bernard Parisse. This flaw represents a critical security weakness that arises from insufficient input validation mechanisms, specifically when processing strings related to the BROWSER environment variable. The vulnerability manifests when the system fails to properly sanitize or validate user-supplied input before executing commands through the designated browser application, creating an avenue for malicious exploitation.
The technical nature of this vulnerability aligns with CWE-74, known as "Improper Neutralization of Special Elements in Output Used by a Downstream Component," and more specifically with CWE-94, "Improper Control of Generation of Code ('Code Injection')." The flaw occurs because the application directly incorporates user-provided data into command execution without adequate sanitization or validation processes. When a remote attacker crafts a malicious URL containing specially formatted input, the system passes this unvalidated data to the BROWSER environment variable, enabling arbitrary command execution. This type of vulnerability falls under the ATT&CK framework's technique T1059.001, "Command and Scripting Interpreter: PowerShell," and T1059.007, "Command and Scripting Interpreter: JavaScript," as attackers can leverage such injection points to execute malicious code through system commands.
The operational impact of this vulnerability is significant as it allows remote attackers to execute arbitrary commands on the affected system with the privileges of the user running the Giac application. This could lead to complete system compromise, data exfiltration, or the installation of additional malicious software. The vulnerability is particularly dangerous in environments where Giac is used for educational purposes or in research settings where users might interact with untrusted web content. Attackers could exploit this weakness to gain unauthorized access to sensitive computational resources, potentially compromising mathematical computations, symbolic processing, or any other functionality that relies on the browser environment variable for external command execution.
Mitigation strategies for CVE-2017-17526 should focus on implementing proper input validation and sanitization mechanisms throughout the application's codebase. The most effective immediate fix involves ensuring that all user-supplied input is properly validated and sanitized before being processed or passed to system commands. Organizations should update to the latest version of Giac where this vulnerability has been addressed, as the maintainers have likely implemented proper input validation for the BROWSER environment variable. Additionally, system administrators should consider implementing strict environment variable controls and monitoring for unusual command execution patterns. The principle of least privilege should be enforced, ensuring that the Giac application runs with minimal required permissions. Network-level protections such as firewalls and intrusion detection systems can help monitor for suspicious command execution patterns, while regular security audits should verify that no similar input validation issues exist in other components of the application or related systems.