CVE-2021-25322 in openSUSE Leap
Summary
by MITRE • 06/10/2021
A UNIX Symbolic Link (Symlink) Following vulnerability in python-HyperKitty of openSUSE Leap 15.2, Factory allows local attackers to escalate privileges from the user hyperkitty or hyperkitty-admin to root. This issue affects: openSUSE Leap 15.2 python-HyperKitty version 1.3.2-lp152.2.3.1 and prior versions. openSUSE Factory python-HyperKitty versions prior to 1.3.4-5.1.
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Analysis
by VulDB Data Team • 06/13/2021
The vulnerability CVE-2021-25322 represents a critical privilege escalation flaw in the python-HyperKitty package affecting openSUSE Leap 15.2 and Factory distributions. This issue stems from improper handling of symbolic links during file operations, creating a pathway for local attackers to elevate their privileges from hyperkitty or hyperkitty-admin user accounts to the root administrative level. The vulnerability specifically impacts versions 1.3.2-lp152.2.2.3 and earlier of the hyperkitty package in openSUSE Leap 15.2, as well as pre-1.3.4-5.1 versions in openSUSE Factory. The flaw demonstrates a classic symlink following vulnerability that operates at the operating system level, allowing malicious actors to manipulate file system operations through symbolic link manipulation.
The technical implementation of this vulnerability involves the python-HyperKitty application's failure to properly validate or sanitize symbolic link references during file processing operations. When the application processes files or directories that contain symbolic links, it follows these links without adequate security checks, potentially allowing an attacker to create malicious symbolic links that point to sensitive system files or directories. This behavior aligns with CWE-59, which describes improper handling of symbolic links, and represents a direct violation of secure file system access controls. The vulnerability typically manifests when the hyperkitty service processes user-generated content or configuration files that may contain crafted symbolic links designed to exploit the privilege escalation opportunity.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it provides attackers with complete system control once successfully exploited. The hyperkitty service typically runs with elevated privileges to manage mailing list archives and related functionality, making it an attractive target for attackers seeking persistent system access. When local users can exploit this vulnerability, they gain root access to the system, enabling them to modify critical system files, install malicious software, establish backdoors, or completely compromise the integrity of the affected system. This vulnerability affects the core security model of the openSUSE distribution by undermining the principle of least privilege and allowing unauthorized users to bypass normal access controls.
Mitigation strategies for CVE-2021-25322 should focus on immediate package updates and system hardening measures. The primary recommendation involves upgrading to python-HyperKitty version 1.3.4-5.1 or later in openSUSE Factory and version 1.3.2-lp152.2.3.1 or later in openSUSE Leap 15.2 to address the underlying symlink handling issues. Additionally, system administrators should implement proper file system permissions and ensure that the hyperkitty service operates with minimal necessary privileges. Network segmentation and monitoring of hyperkitty service operations can help detect potential exploitation attempts. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation techniques and represents a critical weakness in the system's defense-in-depth strategy, as it allows attackers to bypass multiple security layers and gain root access through a single local vulnerability. Organizations should also consider implementing automated patch management systems to ensure timely deployment of security updates and prevent exploitation of similar vulnerabilities in the future.