CVE-2018-6514 in Puppet Agent
Summary
by MITRE
In Puppet Agent 1.10.x prior to 1.10.13, Puppet Agent 5.3.x prior to 5.3.7, Puppet Agent 5.5.x prior to 5.5.2, Facter on Windows is vulnerable to a DLL preloading attack, which could lead to a privilege escalation.
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Analysis
by VulDB Data Team • 02/18/2020
The vulnerability identified as CVE-2018-6514 represents a critical security flaw in Puppet Agent versions prior to specific patch releases, affecting both Windows and Unix-like systems. This vulnerability stems from improper handling of dynamic link library (DLL) loading mechanisms, creating opportunities for malicious actors to execute arbitrary code with elevated privileges. The issue specifically impacts Facter on Windows platforms, which serves as a crucial component for system inventory collection within the Puppet ecosystem. The flaw exists in the way the software resolves and loads dynamic libraries during execution, creating a window of opportunity for attackers to inject malicious code.
This vulnerability operates under the principle of DLL preloading attacks, which exploit the order of library resolution in Windows systems. When Puppet Agent or Facter attempts to load a required DLL, the system searches through a predefined path sequence that can be manipulated by attackers. The vulnerability manifests when the application loads a DLL from an untrusted location, potentially allowing an attacker to place a malicious DLL in a directory that gets searched before the legitimate library. This behavior aligns with CWE-426, which describes the weakness of allowing untrusted libraries to be loaded with elevated privileges. The attack vector is particularly dangerous because it leverages the legitimate privilege escalation mechanisms within the Puppet framework, making it difficult to detect through traditional security controls.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it provides attackers with potential access to sensitive system information and the ability to modify system configurations. When exploited successfully, the vulnerability could allow an attacker to gain administrative privileges on the target system, potentially enabling further attacks within the network. The affected versions of Puppet Agent are widely deployed in enterprise environments, making this vulnerability particularly concerning from a threat perspective. The privilege escalation capability means that even if an attacker initially gains access to a user account, they could elevate their privileges to system level, potentially compromising entire network infrastructures. This vulnerability directly maps to ATT&CK technique T1068, which covers the use of privilege escalation through DLL loading mechanisms.
Mitigation strategies for CVE-2018-6514 primarily focus on applying the vendor-provided patches and updates to affected Puppet Agent versions. Organizations should immediately upgrade to Puppet Agent 1.10.13, 5.3.7, or 5.5.2 respectively, which contain fixes for the DLL preloading vulnerability. System administrators should also implement additional security measures such as restricting write permissions to directories where Puppet Agent and Facter components are installed, implementing application whitelisting policies, and monitoring for suspicious DLL loading activities. The remediation process should include comprehensive testing to ensure that the patch does not introduce compatibility issues with existing Puppet configurations. Security teams should also consider implementing monitoring solutions that can detect anomalous DLL loading patterns, as this vulnerability could be exploited in conjunction with other attack vectors to establish persistent access to target systems.