CVE-2007-5495 in setroubleshoot
Summary
by MITRE
sealert in setroubleshoot 2.0.5 allows local users to overwrite arbitrary files via a symlink attack on the sealert.log temporary file.
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Analysis
by VulDB Data Team • 08/10/2019
The vulnerability identified as CVE-2007-5495 affects the sealert component within setroubleshoot version 2.0.5, representing a critical security flaw that enables local attackers to manipulate system files through symbolic link manipulation. This issue specifically targets the temporary file handling mechanism used by sealert when processing security alerts generated by SELinux. The vulnerability stems from insufficient input validation and improper temporary file creation procedures that allow malicious users to create symbolic links pointing to sensitive system files before the legitimate sealert process attempts to write to its temporary log file.
The technical exploitation of this vulnerability relies on a classic race condition attack pattern where an attacker creates a symbolic link with the name of the temporary file sealert.log in a location where the application will attempt to create or overwrite files. When sealert executes and attempts to write to the temporary file, it follows the symbolic link and writes data to the target file specified by the link rather than the intended temporary location. This fundamental flaw in temporary file handling violates security principles and allows for arbitrary file overwrites with the privileges of the user running sealert, which typically operates with elevated permissions due to its role in system security monitoring.
The operational impact of this vulnerability extends beyond simple file overwrites as it provides attackers with a mechanism to modify critical system files, potentially leading to privilege escalation or system compromise. Attackers can leverage this vulnerability to replace system binaries, modify configuration files, or manipulate security-related data structures, thereby undermining the integrity of the SELinux security framework that setroubleshoot is designed to support. The attack vector is particularly concerning because it requires minimal privileges and can be executed by any local user, making it a significant threat in multi-user environments where system administrators may not properly monitor temporary file usage patterns. This vulnerability directly relates to CWE-367, which addresses time-of-check to time-of-use race conditions, and aligns with ATT&CK technique T1059 for command and scripting interpreter usage as attackers may leverage this to establish persistent access through modified system files.
Mitigation strategies for CVE-2007-5495 should focus on implementing proper temporary file handling practices that prevent symbolic link attacks. System administrators should ensure that setroubleshoot is updated to versions that properly create temporary files with unique names and appropriate permissions, eliminating the possibility of symbolic link manipulation. The recommended approach includes using secure temporary file creation functions that prevent symlink attacks by creating files with exclusive access permissions or employing directory-based isolation techniques where temporary files are created in directories with restricted permissions. Additionally, implementing proper file system permissions and using tools like SELinux policies to restrict access to temporary file locations can significantly reduce the attack surface. Organizations should also conduct regular security audits to identify similar vulnerabilities in other applications that may be susceptible to the same class of race condition attacks, ensuring comprehensive protection against time-of-check to time-of-use vulnerabilities that could be exploited to compromise system integrity and security controls.