CVE-2001-0635 in Linux
Summary
by MITRE
Red Hat Linux 7.1 sets insecure permissions on swap files created during installation, which can allow a local attacker to gain additional privileges by reading sensitive information from the swap file, such as passwords.
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Analysis
by VulDB Data Team • 04/14/2019
The vulnerability identified as CVE-2001-0635 represents a critical security flaw in Red Hat Linux 7.1 installation process that stems from improper file permission handling during system setup. This issue specifically affects swap files created during the installation phase, where the system fails to establish appropriate access controls, creating a persistent security risk that extends beyond the initial installation window. The flaw demonstrates a fundamental misunderstanding of secure system configuration principles where temporary files are not properly secured against unauthorized access.
The technical implementation of this vulnerability occurs when the installation process generates swap files without enforcing restrictive permissions that would normally be applied to sensitive temporary storage areas. These swap files typically contain memory contents that may include passwords, encryption keys, or other confidential data that was temporarily stored in memory during the installation process. The insecure permissions allow local users to access these files directly, bypassing normal access controls that should protect such sensitive information. This represents a classic case of insufficient privilege separation and inadequate temporary file management that violates basic security engineering practices.
The operational impact of this vulnerability extends beyond the immediate installation phase, as the insecure swap files remain accessible on the system post-installation. Local attackers can exploit this weakness by simply reading the swap file contents to extract passwords, authentication tokens, or other sensitive information that was temporarily stored in memory. This creates a persistent backdoor that can be exploited by any user with local access to the system, making it particularly dangerous in multi-user environments where privilege escalation opportunities are limited. The vulnerability essentially transforms the installation process into a vector for privilege escalation, as attackers can leverage the insecure swap files to gain additional system access.
From a cybersecurity perspective, this vulnerability aligns with CWE-732: Incorrect Permission Assignment for Critical Resource, which specifically addresses situations where critical system resources are given inappropriate permissions that allow unauthorized access. The flaw also intersects with ATT&CK technique T1068: Exploitation for Privilege Escalation, as the insecure swap files provide a mechanism for local users to extract sensitive information and potentially escalate their privileges. The vulnerability demonstrates poor adherence to the principle of least privilege and fails to implement proper secure coding practices during system installation. Organizations affected by this vulnerability should immediately implement mitigations including proper file permission enforcement, regular system auditing, and monitoring for unauthorized access to swap files. The remediation process should involve both immediate patching of the installation process and verification that existing swap files have been properly secured to prevent exploitation.