CVE-2018-8415 in Windows
Summary
by MITRE
A tampering vulnerability exists in PowerShell that could allow an attacker to execute unlogged code, aka "Microsoft PowerShell Tampering Vulnerability." This affects Windows 7, PowerShell Core 6.1, Windows Server 2012 R2, Windows RT 8.1, PowerShell Core 6.0, Windows Server 2019, Windows Server 2012, Windows 8.1, Windows Server 2016, Windows Server 2008 R2, Windows 10, Windows 10 Servers.
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Analysis
by VulDB Data Team • 06/06/2023
The CVE-2018-8415 vulnerability represents a critical tampering flaw in Microsoft PowerShell that fundamentally undermines the integrity of script execution processes across multiple Windows operating systems and PowerShell variants. This vulnerability operates at the core of PowerShell's security model by creating a pathway for unauthorized code execution that bypasses normal logging mechanisms, effectively allowing attackers to perform malicious activities without leaving detectable traces in system audit logs. The flaw specifically targets PowerShell's ability to validate and authenticate script execution contexts, creating a window where malicious code can be injected or modified during the execution lifecycle without proper security controls being enforced.
The technical implementation of this vulnerability stems from insufficient validation mechanisms within PowerShell's script execution pipeline, particularly in how the system handles script integrity checks and execution context management. When PowerShell processes scripts, it should maintain strict validation of script origins and modifications, but this vulnerability allows attackers to manipulate script execution flows without triggering the appropriate security alerts or audit trails. The flaw operates at the level of script execution integrity, where PowerShell's built-in safeguards fail to properly monitor or log modifications to script content during runtime, creating a scenario where malicious modifications can occur silently. This represents a direct violation of the principle of least privilege and auditability that should govern all script execution environments.
The operational impact of CVE-2018-8415 extends far beyond simple code execution capabilities, as it fundamentally compromises the security posture of affected systems by enabling stealthy persistence mechanisms and privilege escalation techniques. Attackers can leverage this vulnerability to establish backdoors, deploy malware, or perform reconnaissance activities without detection by traditional security monitoring systems that rely on PowerShell execution logs. The vulnerability affects a broad range of Windows platforms including legacy systems like Windows Server 2008 R2 and modern deployments such as Windows 10 Servers, creating widespread exposure across enterprise environments. This cross-platform impact makes the vulnerability particularly dangerous as it can be exploited across different organizational segments without requiring platform-specific exploitation techniques.
From a cybersecurity framework perspective, this vulnerability aligns with CWE-284 (Improper Access Control) and represents a significant weakness in the principle of least privilege enforcement within PowerShell's security architecture. The ATT&CK framework categorizes this vulnerability under T1059.001 (PowerShell) and T1070.006 (Indicator Removal on Host) as it enables both script execution and logging evasion capabilities. Organizations utilizing PowerShell for administrative tasks, security automation, or system management face heightened risk from this vulnerability, as it essentially provides attackers with a method to execute malicious PowerShell commands while simultaneously hiding their activities from security monitoring systems. The vulnerability's exploitation typically involves crafting malicious PowerShell scripts that can manipulate the execution context without triggering security alerts, making it particularly challenging to detect through conventional security controls.
Mitigation strategies for CVE-2018-8415 require a multi-layered approach combining immediate patch management, enhanced monitoring capabilities, and administrative controls. Microsoft released security updates that address the core validation flaw in PowerShell's script execution pipeline, but organizations must ensure comprehensive deployment across all affected systems including legacy platforms. Enhanced monitoring should focus on PowerShell execution events and script integrity checks, with particular attention to unusual script execution patterns or unauthorized modifications to script files. Administrative controls include implementing strict PowerShell execution policies, disabling unnecessary PowerShell functionality, and establishing robust audit logging configurations that can detect anomalous script execution behaviors. Organizations should also consider implementing application control solutions that can prevent unauthorized PowerShell script execution and maintain detailed logs of all PowerShell activities to detect potential exploitation attempts.