BYO EDR Attack Abuses SentinelOne to Shield Malware
Researchers have demonstrated a 'Bring Your Own EDR' attack that weaponizes SentinelOne components to protect malware, turning the security tool into a shield for malicious code.
A sophisticated "Bring Your Own EDR" attack has been detailed by researchers, which leverages trusted SentinelOne components to effectively shield malware from detection. This novel technique, presented at DEF CON 34, abuses SentinelOne's legitimate functionalities to bypass security measures, including Windows Protected Process Light (PPL) and Microsoft Defender.
The core of the attack exploits a SentinelOne COM interface, specifically a SentinelHelper object, which exposes a 'Dump' method. Crucially, this method reportedly lacks stringent validation, allowing a local administrator to invoke it and create memory dumps of PPL-protected processes. This capability is significant because PPL is designed to prevent ordinary processes from interfering with critical security services, such as EDR agents and Microsoft Defender.
By extracting process-specific secrets from these memory dumps, attackers can then map and execute unsigned code within other PPL-protected processes. The researchers successfully demonstrated a pathway to execute malicious payloads within the protected context of Microsoft Defender, overcoming memory permission, relocation, and dependency-loading restrictions. This bypasses traditional privilege escalation vulnerabilities and kernel exploits, instead relying on the abuse of legitimate, trusted EDR processes.
Beyond direct process manipulation, the attack also targets SentinelOne's installer logic. A crafted registration value could allegedly cause the installer to deploy a non-functional local agent that still reports a secure status, potentially disabling competing endpoint protections. Furthermore, the research highlighted how an agent's management URL could be identified and locally redirected, preventing cloud telemetry collection and delaying detection of malicious activity.
The most severe implication of this attack is the ability to reverse an EDR product's self-protection features. Attackers can place malware in the EDR installation directory, re-enable tamper protection, and then use SentinelOne itself to block other processes from accessing or modifying the hidden malicious payload. This effectively turns the EDR into an unwitting accomplice, shielding the malware from both Windows PPL and the EDR's own detection mechanisms.
SentinelOne has addressed the vulnerability by releasing Agent version 26.1.1. The findings underscore the critical need for robust security controls around EDR management interfaces and installer processes. Organizations are advised to update their SentinelOne agents promptly and to implement stricter controls on local administrator privileges.
Security teams should also proactively monitor for unexpected installer activities and investigate any unusual changes to local DNS or hosts file entries that might affect EDR management domains. The research serves as a stark reminder that endpoint protection solutions, due to their high privileges, must be treated as high-value infrastructure requiring continuous vigilance and secure configuration.