CVE-2017-7540 in Foreman
Summary
by MITRE
rubygem-safemode, as used in Foreman, versions 1.3.2 and earlier are vulnerable to bypassing safe mode limitations via special Ruby syntax. This can lead to deletion of objects for which the user does not have delete permissions or possibly to privilege escalation.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 12/13/2022
The vulnerability identified as CVE-2017-7540 affects rubygem-safemode versions 1.3.2 and earlier when integrated into the Foreman infrastructure management platform. This security flaw represents a critical authorization bypass issue that undermines the intended safe mode restrictions designed to prevent unauthorized access to system resources. The vulnerability specifically targets the sandboxing mechanisms that should limit user execution capabilities within the Foreman environment, creating a pathway for malicious actors to circumvent established permission controls.
The technical implementation of this vulnerability stems from insufficient input validation and sanitization within the rubygem-safemode library. Attackers can exploit specific Ruby syntax patterns that are not properly filtered or restricted by the safe mode implementation. This allows unauthorized users to execute arbitrary code or access objects they should not have permission to manipulate. The flaw operates by leveraging Ruby's dynamic nature and specific parsing behaviors that enable bypassing the intended execution boundaries. The vulnerability is particularly concerning because it can be exploited to perform object deletion operations that require delete permissions, effectively allowing privilege escalation through unauthorized access to restricted system resources.
From an operational perspective, this vulnerability poses significant risks to organizations relying on Foreman for infrastructure management and automation. The ability to bypass safe mode limitations means that authenticated users with minimal privileges could potentially escalate their access rights or cause destructive actions such as object deletion. This represents a direct violation of the principle of least privilege and could lead to complete system compromise if exploited by malicious insiders or external attackers who gain initial access. The impact extends beyond simple permission bypass to potentially enable broader system infiltration and data destruction capabilities.
The vulnerability aligns with CWE-284, which addresses improper access control issues, and demonstrates characteristics consistent with privilege escalation vulnerabilities. It also maps to ATT&CK technique T1068, which covers "Exploitation for Privilege Escalation" by providing a method for users to gain elevated system privileges through application-level flaws. Organizations should prioritize immediate remediation by upgrading to rubygem-safemode versions that address this vulnerability, implementing additional access controls, and monitoring for suspicious activities that might indicate exploitation attempts. The fix typically involves strengthening input validation, enhancing Ruby syntax filtering, and ensuring proper sandbox boundary enforcement to prevent the specific syntax patterns that enable the bypass.