CVE-2020-7261 in Endpoint Security
Summary
by MITRE
Buffer Overflow via Environment Variables vulnerability in AMSI component in McAfee Endpoint Security (ENS) Prior to 10.7.0 February 2020 Update allows local users to disable Endpoint Security via a carefully crafted user input.
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Analysis
by VulDB Data Team • 05/27/2024
The CVE-2020-7261 vulnerability represents a critical buffer overflow flaw within the Antimalware Scan Interface (AMSI) component of McAfee Endpoint Security (ENS) versions prior to 10.7.0. This vulnerability specifically manifests through environment variables and provides local attackers with the capability to disable endpoint security protections, effectively compromising the system's defensive posture. The issue stems from improper input validation and memory management within the AMSI integration layer that processes user-supplied environment variables during security scanning operations.
The technical implementation of this vulnerability involves a classic buffer overflow condition where maliciously crafted environment variable content exceeds the allocated memory buffer size in the AMSI component. This overflow occurs when the system processes environment variables that are passed to the AMSI interface during malware scanning operations. The flaw is categorized under CWE-121 as a stack-based buffer overflow, where insufficient bounds checking allows attackers to overwrite adjacent memory locations. The vulnerability is particularly dangerous because it operates at the kernel level within the AMSI subsystem, enabling attackers to manipulate critical security functions without requiring elevated privileges beyond standard user access.
From an operational impact perspective, this vulnerability creates a significant risk for enterprise environments as it allows local users to disable endpoint protection mechanisms entirely. Attackers can exploit this weakness to bypass security controls, potentially enabling further malicious activities such as malware installation, privilege escalation, or data exfiltration. The vulnerability's local nature means that any user account with access to the system can potentially exploit this flaw, making it particularly concerning for organizations with shared or multi-user environments. The ability to disable security protection through environment variable manipulation represents a sophisticated attack vector that aligns with techniques described in the MITRE ATT&CK framework under T1059 for command and scripting interpreter and T1566 for credential harvesting through manipulation of system components.
The exploitation process involves crafting specific environment variables that trigger the buffer overflow condition within the AMSI component, ultimately leading to the disabling of endpoint security services. This vulnerability impacts organizations using McAfee ENS versions earlier than 10.7.0, making it a critical concern for enterprises that have not yet applied the February 2020 security update. Organizations should immediately implement the vendor-provided patch to address this vulnerability, as the window for exploitation remains open for unpatched systems. Security teams should also monitor for potential exploitation attempts through unusual environment variable usage patterns and implement additional controls such as environment variable restrictions to limit the attack surface. The vulnerability demonstrates the importance of proper input validation and memory management in security-critical components, as outlined in industry best practices for secure coding standards and defensive programming techniques.