CVE-2015-7529 in SOSreport
Summary
by MITRE
sosreport in SoS 3.x allows local users to obtain sensitive information from sosreport files or gain privileges via a symlink attack on an archive file in a temporary directory, as demonstrated by sosreport-$hostname-$date.tar in /tmp/sosreport-$hostname-$date.
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Analysis
by VulDB Data Team • 07/06/2022
The vulnerability identified as CVE-2015-7529 resides within the sosreport utility of the SoS 3.x framework, a system administration tool designed to collect diagnostic information from Linux systems. This flaw represents a classic symlink attack scenario that exploits improper handling of temporary files during the archiving process. The vulnerability specifically targets the temporary directory structure used by sosreport, where archive files are created with predictable naming conventions such as sosreport-$hostname-$date.tar in the /tmp directory. The security implications arise from the tool's failure to properly validate or secure temporary file creation processes, creating opportunities for privilege escalation and information disclosure.
The technical exploitation of this vulnerability leverages the insecure temporary file creation pattern commonly found in Unix-like systems. When sosreport executes, it creates temporary archive files in the /tmp directory without sufficient security controls to prevent symlink attacks. An attacker with local access can create malicious symbolic links in the temporary directory that point to sensitive system files or locations. When sosreport attempts to create its archive file, the tool follows the symbolic links and writes data to unintended locations, potentially overwriting critical system files or exposing sensitive information from the target files that the symbolic links reference. This type of vulnerability maps directly to CWE-377: Insecure Temporary Files and CWE-378: Creation of Temporary File With Insecure Permissions, both of which fall under the broader category of insecure file handling practices.
The operational impact of CVE-2015-7529 extends beyond simple information disclosure to potentially enable privilege escalation within affected systems. Local attackers can exploit this vulnerability to gain elevated privileges by overwriting system binaries or configuration files through the symlink mechanism. The attack vector is particularly concerning because it requires minimal privileges to execute and can be automated to target systems running the affected SoS versions. In enterprise environments where sosreport is commonly used for system diagnostics, this vulnerability creates a persistent security risk that could be exploited by malicious insiders or compromised local accounts. The vulnerability also aligns with ATT&CK technique T1059.001 for Command and Scripting Interpreter, as attackers can leverage the compromised sosreport functionality to execute arbitrary commands through file overwrites.
Mitigation strategies for CVE-2015-7529 should focus on implementing proper temporary file handling procedures and addressing the root cause of the insecure symlink attack. System administrators should immediately upgrade to patched versions of SoS that implement proper temporary file creation methods, including using secure temporary directory permissions and atomic file creation techniques. The recommended approach involves setting appropriate umask values, creating temporary files with unique identifiers, and implementing proper file permission controls that prevent symbolic link resolution during file creation. Additionally, implementing proper directory permissions for /tmp and related temporary directories can help mitigate the attack surface. Organizations should also consider implementing monitoring for suspicious file creation patterns in temporary directories and establish proper access controls to limit local user privileges where possible. The vulnerability demonstrates the importance of following secure coding practices for temporary file handling and aligns with security best practices outlined in the Open Web Application Security Project (OWASP) secure coding guidelines for preventing temporary file vulnerabilities.