CVE-2021-43940 in Confluence Server
Summary
by MITRE • 02/15/2022
Affected versions of Atlassian Confluence Server and Data Center allow authenticated local attackers to achieve elevated privileges on the local system via a DLL Hijacking vulnerability in the Confluence installer. The affected versions are before version 7.4.10, and from version 7.5.0 before 7.12.3.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 10/09/2024
The vulnerability identified as CVE-2021-43940 represents a critical privilege escalation flaw within Atlassian Confluence Server and Data Center platforms. This vulnerability specifically targets the Confluence installer component and exploits a DLL hijacking mechanism that allows authenticated local attackers to elevate their privileges on the affected system. The flaw exists in the installation process where the system fails to properly validate or restrict the loading of dynamic link library files, creating an opportunity for malicious code execution with elevated system permissions.
The technical implementation of this vulnerability stems from improper handling of dynamic library loading during the Confluence installation process. When an attacker with local access executes the installer, the system's dynamic link library search order mechanism can be manipulated to load malicious DLL files instead of legitimate ones. This occurs because the installer does not enforce strict validation of library paths or implement proper security controls to prevent unauthorized DLL loading. The vulnerability manifests when the system searches for required libraries in predictable locations where an attacker could place malicious binaries, effectively enabling code execution with the privileges of the installer process.
From an operational perspective, this vulnerability poses significant risks to organizations running affected Confluence versions. The requirement for local authentication means that attackers must first gain access to a system with valid user credentials, but once achieved, they can leverage this flaw to escalate privileges and potentially gain full system control. This presents a particular threat vector for attackers who have already compromised user accounts or gained access through other means, as they can use this vulnerability to move laterally within the network and establish persistent access. The impact extends beyond simple privilege escalation to potentially enable complete system compromise, especially when combined with other exploitation techniques.
Organizations should immediately implement mitigations including upgrading to versions 7.4.10 or 7.12.3 and later, as these releases contain patches addressing the DLL hijacking vulnerability. System administrators should also enforce strict access controls and monitor for unauthorized local access attempts. The vulnerability aligns with CWE-427 Uncontrolled Search Path Element, which specifically addresses the issue of insecure library loading mechanisms. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation techniques under T1068, where adversaries exploit weaknesses in system processes to gain elevated privileges. Additionally, the requirement for local access places this vulnerability in the context of T1078 Valid Accounts, as attackers must first establish a foothold with legitimate credentials before exploiting this weakness.
The broader implications of this vulnerability highlight the importance of secure software installation practices and proper library loading mechanisms. Organizations should conduct thorough security assessments of their installation processes and implement strict controls around dynamic library loading. Regular security updates and patch management procedures become critical in preventing exploitation of such vulnerabilities. System monitoring should include detection of unusual library loading patterns and unauthorized local access attempts to identify potential exploitation of this and similar privilege escalation vulnerabilities.