CVE-2018-8416 in .NET Core
Summary
by MITRE
A tampering vulnerability exists when .NET Core improperly handles specially crafted files, aka ".NET Core Tampering Vulnerability." This affects .NET Core 2.1.
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Analysis
by VulDB Data Team • 06/06/2023
The CVE-2018-8416 vulnerability represents a critical tampering issue within Microsoft's .NET Core 2.1 framework that fundamentally compromises the integrity of file handling operations. This vulnerability stems from improper validation mechanisms within the runtime environment that fails to adequately verify the authenticity and integrity of specially crafted files before processing them. The flaw specifically manifests when the .NET Core runtime encounters malformed or maliciously constructed files that exploit gaps in the validation logic, potentially allowing unauthorized modifications to occur during the file processing lifecycle.
From a technical perspective, this vulnerability operates at the core file handling and validation layers of the .NET Core 2.1 runtime environment, creating opportunities for attackers to manipulate file contents or metadata in ways that bypass normal security controls. The issue is categorized under CWE-220 which specifically addresses improper handling of files or data that can lead to tampering vulnerabilities. The vulnerability's impact extends beyond simple file corruption as it can enable attackers to inject malicious code or alter legitimate file contents, potentially leading to privilege escalation or system compromise. The flaw exists within the runtime's file validation routines where insufficient input sanitization allows crafted payloads to pass through security checks that should have prevented their processing.
The operational impact of CVE-2018-8416 is substantial as it affects any application built on .NET Core 2.1 that processes external files or user-supplied data. Attackers can exploit this vulnerability to modify application files, inject malicious code into legitimate processes, or manipulate configuration files that could lead to unauthorized system access. The vulnerability's exploitation typically requires an attacker to have the ability to influence file contents or to place malicious files within the application's processing path, making it particularly dangerous in environments where file uploads or external data processing are common. This weakness can be leveraged as part of a broader attack chain that aligns with ATT&CK technique T1059.001 for executing malicious code through file manipulation.
Organizations utilizing .NET Core 2.1 applications must implement immediate mitigations to address this vulnerability, including applying the official Microsoft security patches released for this issue. The recommended approach involves upgrading to a patched version of .NET Core 2.1 or migrating to a supported version that contains the necessary security fixes. Additional defensive measures should include implementing strict file validation controls, employing file integrity monitoring systems, and establishing robust access controls to limit the potential impact of exploitation. Security teams should also consider implementing network segmentation and monitoring for suspicious file processing activities that could indicate exploitation attempts, as the vulnerability may not always be immediately detectable through standard security controls.