CVE-2021-37852 in Endpoint Antivirus
Summary
by MITRE • 02/09/2022
ESET products for Windows allows untrusted process to impersonate the client of a pipe, which can be leveraged by attacker to escalate privileges in the context of NT AUTHORITY\SYSTEM.
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Analysis
by VulDB Data Team • 02/12/2022
The vulnerability identified as CVE-2021-37852 affects ESET security products running on Windows operating systems and represents a critical privilege escalation flaw that can be exploited by attackers to gain SYSTEM-level access. This vulnerability specifically targets the inter-process communication mechanisms used by ESET products, creating a pathway for malicious actors to elevate their privileges from standard user level to the highest possible system privileges. The flaw exists within the pipe impersonation functionality that ESET products utilize for communication between different process components, making it particularly dangerous as it leverages legitimate system mechanisms that are typically trusted by the operating system.
The technical root cause of this vulnerability stems from insufficient validation of pipe client identities within ESET's Windows implementation. When a process establishes communication through named pipes, the system should verify that the connecting client is legitimate and authorized to perform specific operations. However, ESET products fail to properly authenticate pipe clients, allowing untrusted processes to masquerade as legitimate pipe clients. This occurs because the software does not adequately validate the security context of incoming pipe connections, enabling attackers to exploit this weakness through carefully crafted malicious processes that can impersonate authorized clients. The vulnerability manifests when the ESET service processes accept connections from these impersonating processes without proper authentication checks, effectively allowing unauthorized code execution with elevated privileges.
The operational impact of CVE-2021-37852 is severe and potentially devastating for affected organizations. Attackers who successfully exploit this vulnerability can achieve complete system compromise by elevating their privileges to NT AUTHORITY\SYSTEM, which provides unrestricted access to all system resources, files, and processes. This privilege escalation capability enables attackers to install persistent backdoors, exfiltrate sensitive data, modify system configurations, and establish long-term access to compromised systems. The vulnerability is particularly concerning because it affects security products that are typically considered trusted components of the system, making detection and prevention more challenging. Organizations running ESET products on Windows systems are at significant risk, as the exploit requires minimal privileges to initiate and can be automated to target multiple systems simultaneously.
Organizations should immediately apply the vendor-provided patches and updates released to address this vulnerability, as ESET has acknowledged and remediated the issue in their security products. System administrators should conduct comprehensive vulnerability assessments to identify any systems running affected ESET products and ensure all patches are properly deployed across the enterprise environment. Additionally, implementing network segmentation and privilege separation measures can help reduce the potential impact of such exploits, while monitoring for unusual pipe connection patterns and unauthorized process activities can aid in early detection of exploitation attempts. The vulnerability aligns with CWE-284, which addresses improper access control, and represents a classic example of privilege escalation through inadequate authentication mechanisms. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation techniques that leverage trusted system components and process injection methods, making it particularly dangerous in enterprise environments where security products are expected to provide protection rather than serve as attack vectors.